There is a good deal of variation in the colour of the fur, the prevailing tint being grey.
The greatest variation, however, is seen in the tentacles.
varius), there is much individual variation in this respect, scarcely any two being alike.
One variation is illustrated in fig.
The Italian and Sicilian Albanians are of Tosk descent, and many of them still speak a variation of the Tosk dialect.
The extent of the area affected and of the variation in the turgor depends upon many circumstances, but we have no doubt that in the process of modifying its own permeability by some molecular change we have the counterpart of muscular contractibility.
It has been the habit of biologists to use the terms variation, selection, elimination, correlation and so forth, vaguely; the new school, which has been strongly reinforced from the side of physical science, insists on quantitative measurements of the terms. When the anatomist says that one race is characterized by long heads, another by round heads, the biometricist demands numbers and percentages.
"Only once in my life to get an old wolf, I want only that!" thought he, straining eyes and ears and looking to the left and then to the right and listening to the slightest variation of note in the cries of the dogs.
The diurnal variation in summer at the latter station is shown graphically in the top curve of fig.
deals with the variation of thunder over longer periods.
Stas carried out such experiments on the composition of silver chloride and of ammonium chloride, but he never found a variation of one part in 10,000 in the composition of the substances.
There is a difficulty in reconciling observed values of the ionization with the results obtained from balloon ascents as to the variation of the potential with altitude.
The two last curves in the diagram contrast the diurnal variation at Kew in potential gradient and in barometric pressure for the year as a whole.
the variation throughout the year diminishes as one approaches the equator.
The diurnal variation showed only a single maximum and minimum, between 5 and 6 P. M.
The shape mostly used is the " saddle " boiler, or some variation upon this very old pattern.
But with all these often opposed conditions, we find less variation than might be expected, the main and really important divergence being due to the necessity of transposition, which added a very high pitch to the primarily convenient low one.
But the causes and conditions of variation have yet to be thoroughly explored; and the importance of natural selection will not be impaired, even if further inquiries should prove that variability is definite, and is determined in certain directions rather than in others, by conditions inherent in that which varies.
At Karasjok and Kremsmunster the seasonal variation in a i seems comparatively small, but at Potsdam and the Bureau Central it is as large as at Kew.
The opening and closing of the stomata is the result of variation in the turgidity 01 their guard cells, which is immediately affected by the condition of turgidity of the cells of the epidermis contiguous to them.
- Annual Variation Potential Gradient.
These are discussed under the headings Heredity; Mendelism; and Variation And Selection.
There Seems A Fairly Well Marked Annual Variation In Ionic Contents, As The Following Figures Will Show.
The winds are liable to little variation; they blow from the west, often with great violence, for nine months in the year, and at other times from the north; and they moderate the summer heats, which are chiefly felt during the months of July and August, when the hot winds blow from the coast of Anatolia.
He maintained that, under varying conditions, two substances could combine in an indefinitely large number of different ratios, that there could in fact be a continuous variation in the combining ratio.
In 1727 he gained the prize given by the Academie des Sciences for his paper "On the best manner of forming and distributing the masts of ships"; and two other prizes, one for his dissertation "On the best method of observing the altitude of stars at sea," the other for his paper "On the best method of observing the variation of the compass at sea."
The calyptoblastic polyp of the nutritive type is very uniform in character, its tendency to variation being limited, as it were, by the enclosing hydrotheca.
The turgidity in the cells of a growing member is not uniform, but shows a fairly rhythmical variation in its different parts.
An important variation is seen, in the form of the hydrotheca itself, which may come off from the main stem by a stalk, as in Obelia, or may be sessile, without a stalk, as in Sertularia.
The somewhat remarkable resemblance between the diurnal variation for the two elements, first remarked on by J.
This subject brings the domain of pathology, however, into touch with that of variation, and we are profoundly ignorant as to the complex of external conditions which would decide in any given case how far a variation in form would be prejudicial or otherwise to the continued existence of a species.
He also found a marked diurnal variation, A being considerably greater between 3 and 5 A.M.
One important variation, however, was a clause in the bill of rights providing for the abolition of slavery, Vermont being the first state in America to take such action.
and intended to eliminate irregular changes, but they also to some extent eliminate regular changes if the hours of maxima and minima or the character of the diurnal variation alter throughout the year.
variation in resistance of the transmitter spoken into causes a variation of the pressure at the line terminals of the impedance coils, and since those terminals are common to the two circuits the variable E.M.F.
The following are a few of the more general works: Bateson, Materials for the Study of Variation; Bunge, Vitalismus and Mechanismus; Cope, Origin of the Fittest, Primary Factors of Organic Evolution, Darwin's Life and Letters; H.
The average daily variation of the thermometer is from 67° to 83° F.
The fact of variation is a familiar one.
[[Table Xii]].-Diurnal Variation of Thunderstorms. centages.
vary somewhat from year to year, there is not much variation in the proportions.
Variation Of Specific Heat Of Water.
Such a variation can be detected by the spectroscope.
This transformation is due to new characters arising through variation.
Compound working permits of a greater range of expansion than is possible with a simple engine, and incidentally there is less range of pressure per cylinder, so that the pressures and temperatures per cylinder have not such a wide range of variation.
Since the atomic heat of the same element varies with its state of aggregation, it must be concluded that some factor taking this into account must be introduced; moreover, the variation of specific heat with temperature introduces another factor.
The term (dh/0 - d4)) depending on the variation of the specific heat of the liquid may be made very small in the case of water by a proper choice of the constant s'.
Its original use was the determination of geographical latitudes in the field work of geodetic operations; more recently it has been extensively employed for the determination S of variation of latitude, at fixed stations, under the auspices of the International Geodetic Bureau, and for the astronomical determination of the constant of aberration.
In the second zone the climate is more temperate and there is considerable variation in temperature owing to nocturnal radiation.
of divine government of the universe, the recognition of a large number of gods and their consorts by the side of Marduk remained a firmly embedded doctrine in the Babylonian religion as it did in the Assyrian religion, with the important variation, however,.
The advantage of the method is that there is no transference or mixture; the defect is that the whole measurement depends on the assumption that the rate of loss of heat is the same in the two cases, and that any variation in the conditions, or uncertainty in the rate of loss, produces its full effect in the result, whereas in the previous case it would only affect a small correction.
These methods have reached their highest development in connexion with the determination of the mechanical equivalent of heat, but they may be applied with great advantage in connexion with other problems, such as the measurement of the variation of specific heat, or of latent heats of fusion or vaporization.
The Results Considered With Reference To The Variation Of Fig.
The Extreme Variation Of Results In Any One Series Was Only From 776.63 To 779.46 Ft.
This Variation May Have Been Due To The State Of The Lagging, Which Moorby Distrusted In Spite Of The Great Reduction Of The Heat Loss, Or It May Have Been Partly Due To The Difficulty Of Regulating The Speed Of The Engine And The Watersupply To The Brake In Such A Manner As To Maintain A Constant Temperature In The Outflow, And Avoid Variations In The Heat Capacity Of The Brake.
The Largest Variation Recorded In The Two Trials Of Which Full Details Are Given, Was 4 9° F.
It Would Have Been Desirable, If Possible, To Have Tried The Effect Of A Larger Range Of Variation In The Experimental Conditions Of Load And Speed, With A View To Detect The Existence Of Constant Errors; But Owing To The Limitations Imposed By The Use Of A Steam Engine, And The Difficulty Of Securing Steady Conditions Of Running, This Proved To Be Impossible.
In Spite Of The Large Corrections The Results Were Extremely Consistent, And The Value Of The Temperature Coefficient Of The Diminution Of The Specific Heat Of Water, Deduced From The Observed Variation In The Rate Of Rise At Different Points Of The Range 15° To 25°, Agreed With The Value Subsequently Deduced From Rowland'S Experiments Over The Same Range, When His Thermometers Were Reduced To The Same Scale.
The Question Of The Variation Of The Specific Heat Of Water Has A Peculiar Interest And Importance In Connexion With The Choice Of A Thermal Unit.
We May Probably Take The Tabulated Values As Showing Correctly The Rate Of Variation Between 110° And 190° C., But The Values In Terms Of Any Particular Thermal Unit Must Remain Uncertain To At Least 0.5% Owing To The Uncertainties Of The Thermometry.
Bosscha From An Independent Reduction Of Regnault'S Experiments Is Probably Within The Limits Of Accuracy Between Ioo° And Zoo° C., So Far As The Mean Rate Of Variation Is Concerned, But The Absolute Values Require Reduction.
According To The Electric Method, The Whole Range Of Variation Of The Specific Heat Between 10° And 80° Is Only O.
It Must Be Admitted That It Is Desirable To Redetermine The Variation Of The Specific Heat Above 100° C. This Is Very Difficult On Account Of The Steam Pressure, And Could Not Easily Be Accomplished By The Electrical Method.
But For Purposes Of Definition It Would Be Necessary To Take The Mean Value Of The Specific Heat Over A Given Range Of Temperature, Preferably At Least 10°, Rather Than The Specific Heat At A Point Which Necessitates Reference To Some Formula Of Reduction For The Rate Of Variation.
The Experimental Evidence, However, Is Somewhat Conflicting, And Further Investigations Are Very Desirable On The Variation Of Specific Heat With Temperature.
Given The Specific Heat As A Function Of The Temperature, Its Variation With Pressure May Be Determined From The Characteristic Equation Of The Gas.
A, 1901, " On The Variation Of The Specific Heat Of Water"; For Combustion Methods, See Article Thermochemistry, And Treatises By Thomsen, Pattison Muir And Berthelot; See Also Articles Thermodynamics And Vaporization.
The range of variation is much smaller, the difference between maximum and minimum rarely exceeding two magnitudes.
When the orbits are eccentric, the tidal disturbance varying with the distance between the two components will probably cause changes in their absolute brilliancy; the variation due to change in the aspect of the system presented to us may thus be supplemented by a real intrinsic variation, both, however, being regulated by the orbital motion.
A large eccentricity also produces an unsymmetrical light variation, the minimum occurring at a time not midway between two maxima; stars of this character are called Cepheid variables, after the typical star S Cephei.
59 m., and the range of variation between 0.7 and 1.4 magnitudes.
Except when the line of sight is perpendicular to the plane of the orbit, the revolution of the two bodies will result in a periodic variation of the motion in the line of sight.
The third registers its quantitative variation according to quantitative changes in its concomitants.
Owing to the variation in the value of the dielectric constant of glass with the temperature and with the frequency of the applied electromotive force, and also owing to electric glow discharge from the edges of the tin foil coatings, the capacity of an ordinary Leyden jar is not an absolutely fixed quantity, but its numerical value varies somewhat with the method by which it is measured, and with the other circumstances above mentioned.
(II) This relation gives a linear formula for the variation of the total heat, a result which agrees in form with that found by Regnault for steam, and implies that the coefficient of t in his formula should be equal to the specific heat S of steam.
Adopting this definition, without restriction to the case of an ideal vapour or to saturation-pressure, the rate of variation of the total heat with temperature (dH/dO) at constant pressure is equal to S under all conditions, whether S is constant, or varies both with p and 0.
- The question of the measurement of the specific heat of a vapour possesses special interest on account of this simple theoretical relation between the specific heat and the variation of the latent and total heats.
1.40, Rankine found S = .385, a value which he used, in default of a better, in calculating some of the properties of steam, although he observed that it was much larger than the coefficient .305 in Regnault's formula for the variation of the total heat.
From a different point of view, equation (12) may be applied to determine the specific heat of steam in terms of the rate of variation of the total heat.
These results for the variation of Q are independent of any assumption with regard to the variation of H.
Whatever may be the objections to Regnault's method of measuring the specific heat of a vapour, it seems impossible to reconcile so wide a range of variation of S with his value 5=0.475 between 125° and 225° C. It is also extremely unlikely that a vapour which is so stable a chemical compound as steam should show so wide a range of variation of specific heat.
The experimental results of Grindley with regard to the mode of variation of Q have been independently confirmed by Callendar (Proc. R.S.
The method of deducing the specific heat from Regnault's formula for the variation of the total heat is evidently liable in a greater degree to the objections which have been urged against his method of determining the specific heat, since it makes the value of the specific heat depend on small differences of total heat observed under conditions of greater difficulty at various pressures.
Regnault's formula for the total heat is here again seen to be inadmissible, as it would make the latent heat of steam vanish at about 870° C. instead of at 365° C. It should be observed, however, that the assumptions made in deducing the above formulae apply only for moderate pressures, and that the formulae cannot be employed up to the critical point owing to the uncertainty of the variation of the specific heats and the cooling effect Q at high pressures beyond the experimental range.
The rate of variation of the latent heat at low pressures is equal to S-s, where s is the specific heat of the liquid.
The approximate equation of Rankine (23) begins to be I or 2% in error at the boiling-point under atmospheric pressure, owing to the coaggregation of the molecules of the vapour and the variation of the specific heat of the liquid.
Omitting w and neglecting the small variation of the specific heat of the liquid, the result is simply the addition of the term (c-b)/V to formula (23) log p=A+B/B - I - C log B-f-(c-b)IV..
The most uncertain data are the variation of the specific heat of the liquid and the value of the small quantity b in the formula (13).
The effect of variation of the specific heat is more important, but is nearly eliminated by the form of the equation.
1900, loc. cit.) that the effect of the variation of the specific heat of the liquid is represented in the equation for the vapour-pressure by adding to the right-hand side of (23) the term - (d4-dh/9)/R.
1902) for the specific heat of water between ioo° and 200° C., we find the values of the difference (d4-dh/9) to be less than one-tenth of do at 200° C. The whole correction is therefore probably of the same order as the uncertainty of the variation of the specific heat itself at these temperatures.
It is equivalent, as Callendar (loc. cit.) points out, to supposing that the variation of the specific heat is due to the formation and solution of a mass w/(v-w) of vapour molecules per unit mass of the liquid.
The difference has been productive of no other inconvenience than arises from the variation of a month in the celebration of the festivals.
That is, the variation of mean annual temperatures for different parts of the state is only 6° F.
The daily and annual variation is very great, and is intensified toward the E., where the altitudes are greater.
since the initial and final temperatures, which alone determine the variation in the thermal effect, are in almost all cases within the ordinary laboratory range of a few degrees, this influence may in general be neglected without serious error.
where do is the corresponding residual variation of 0', and is easily calculated from a table of values of h.
Admitting the value S =0.497 for the specific heat at 108° C., it is clear that the form of Regnault's equation (io) must be wrong, although the numerical value of the coefficient 0.305 may approximately represent the average rate of variation over the range (loo° to 190° C.) of the experiments on which it chiefly depends.
37, p. 504, 1889) to give values of the total heat to to 6 calories too large between o° and 40° C. At low pressures and temperatures it is probable that saturated steam behaves very nearly as an ideal gas, and that the variation of the total heat is closely represented by Rankine's equation with the ideal value of S.
(is) The index n in the above formula, representing the rate of variation of c with temperature, is approximately the same as that expressing the rate of variation of the cooling effect Q, which is nearly proportional to c, and is given by the formula SQ= (n+i)c - b..
(14) The corresponding formula for the total heat is H - Ho=So(O-00) - (n 1) (cp - copo)+ b(p - po), 0E5) and for the variation of the specific heat with pressure S = So+n(n+ i) pc/O,.
If the pressure alters as the water tank empties, a discontinuity occurs in the trace when the tank is refilled, and a fictitious element may be introduced into the diurnal variation.
The result, if considered alone, inevitably leads to an underestimate of the average amplitude of the regular diurnal variation.
If V be the potential, p the density of free electricity at a point in the atmosphere, at a distance r from the earth's centre, then assuming statical conditions and neglecting variation of V in horizontal directions, we have r2 (d/dr) (r 2 dV/dr) - - 4.rp = o.
some plants of changing their position in the cell under the stimulus of a variation in the intensity of the light rays which fall upon them.
The evolution of higher from lower plants, it is generally assumed, has proceeded by variation.
With regard to the causation of variation Darwin says (Origin of Species, ch.
In spite of the statement that the nature of the organism is the most important factor in variation, the tendency amongst evolutionists has been to take much more account of the influence of external conditions.
1.), and Nageli, who attributes variation to causes inherent in the idioplasm, and has elaborately worked out the view in his Abstammungslehre.
It is inconceivable that external conditions can impart to an organism the capacity to develop something that it does not already possess: can impart to it, that is, the capacity for variation in the direction of higher complexity.
AdaptationThe morphological and physiological differentiation of the plant-body has, so far, been attributed to (I) the nature of the organism, that is to its inherent tendency towards higher organization, and (2) to the indefinite results of the external conditions acting as a stimulus which excites the organism to variation, but does not direct the course of variation.
This so-called direct effect of external conditions upon the form and structure of the body differs from the indirect effect in that the resulting variations bear a relation, of the nature of adaptation, to those conditions; the effect of the conditions is not only to cause variation, but to cause variation in a particular direction.
- In the one case the stimulus induces indefinite variation, in the other definite; but no hard-and-fast line can be drawn between them.
Thus it has come to pass that the muscles of the hind limbs are, like their framework, more easily compared with those of reptiles and mammals than are the wings, whilst within the class of birds they show an enormous amount of variation in direct correlation with their manifold requirements.
In one instance the variation is so excessive that it fully justifies the establishment of a specific distinction.
In the same species, however, great variation occurs in the development of the mandibles, and the breadth of the head varies correspondingly, the smallest type of male being but little different in appearance from the female.
These are the permanent outlines of what may be called the philosophy of mysticism in Christian times, and it is remarkable with how little variation they are repeated from age to age.
In southern Asia, and particularly near the sea, the variation between the hottest and coldest monthly means is very much less, and under the equatorit is reduced to about 5°.
But within this region there is a very great variation between the vegetation of the more humid and the more arid regions, while the characteristics of the flora on the higher mountain ranges differ wholly from those of the plains.
It seems certain that success in any system involving a more extended growth of leguminous crops in rotations must be dependent on a considerable variation in the description grown.
Under an apparently uniform and stable system of social regulation there was much variation and movement, the significance of which it is impossible to estimate.
Triforis, Physa, Clausilia are examples of sinistral Gastropods, but reversal also occurs as an individual variation among forms normally dextral.
As in other Molluscan groups, we find a wide variation in the early process of the formation of the first embryonic cells, and their arrangement as a diblastula, dependent on the greater or less amount of food-yolk which is present in the egg-cell when it commences its embryonic changes.
Two years later Nitzsch, who was indefatigable in his endeavour to discover the natural families of birds and had been pursuing a series of researches into their vascular system, published the result, at Halle in Saxony, in his Observationes de avium arteria carotide communi, in which is included a classification drawn up in accordance with the variation of structure which that important vessel presented in the several groups that he had opportunities of examining.
Of course the variation to which the number of primaries was subject had not.
The mean rise and fall of the tide is about 2 ft., but under certain conditions of wind the variation amounts to 5 ft.
Otherwise its only variation is between pointed and rounded loops and B).
Eimer and Herbert Spencer; variation by W.
The principal varieties of Egyptian cotton are: Mitafifi, the bestknown and most extensively grown, hardy and but little affected by climatic variation.
Now frequency of movement, average daily price variation, and range of price movements are matters of fundamental importance to the public. Hence for practical purposes we require several kinds of measurement of price movements, and it is impossible to weigh exactly the one against the other in respect of importance.
In one day, for instance, when the net drop was 33 points and the range of variation 59 points (namely, 8.45 to 7.86), 150 price fluctuations were recorded.
The mean daily variation at San Juan is 11 5°; on the mountains the mean daily variation is 23°.
The existence, therefore, of much variation in the practice of the festival in historic times is scarcely proved by the seeming variations of the enactments concerning it in the Pentateuch.
The ordinary variation is from 3 to 4 degrees, the mean maximum reading in the shade in a cooler district being about 105° as against 108° in the hotter ones for the month of May, and 79° as against 83° for the month of December.
The allotropy of arsenic and antimony is also worthy of notice, but in the case of the first element the variation is essentially non-metallic, closely resembling that of phosphorus.
The first cause of variation may be at present ignored; its significance will become apparent when we consider dispersion (vide infra).
8 shows the variation of refractive index of mixed crystals of potash alum and thallium alum with variation in composition.
A further difficulty arose in connexion with the variation of the compass, which induced Pedro Reinel Behaim'S Globe 1492 Fig.
The first maps illustrating the variation of the compass were published by Chris.
Edmund Halley, the astronomer, compiled the first variation chart of scientific value (1683), as also a chart of the winds (1686).
Delisle in 19 sheets (1739-1745); charts illustrating the variation of the compass and of magnetic " dip " by E.
Temperature is as a rule high but with considerable variation, from 60° F.
trepidare, to tremble), a term meaning, in general, fear or trembling, but used technically in astronomy for an imagined slow oscillation of the ecliptic, having a period of 7000 years, introduced by the Arabian astronomers to explain a supposed variation in the precession of the equinoxes.
Granted that instinctive modes of behaviour are hereditary and definite within the limits of congenital variation, the question of their manner of genesis is narrowed to a clear issue.
Some daily variation in the temperature of adjoining localities is caused by a dark soil in the one and a light soil in the other, but the differences of mean annual temperature are almost wholly due to differences of latitude and elevation.
A variation from this was provided as soon as the priority bonds should become extinct; but these bonds having since been repaid (as mentioned below) by a further issue of unified bonds, this variation lapses.
Amid all the variation in their details, and the apparent confusion introduced by Napoleon's habit of suggesting alternatives and discussing probabilities, and in spite of the preparations ostensibly made for an expedition to Ireland, which was to have sailed from Brest and to have carried 30,000 troops commanded by Augereau, the real purpose of Napoleon was neither altered nor concealed.
The nectarine is a variation from the peach, mainly characterized by the circumstance that, while the skin of the ripe fruit is downy in the peach, it is shining and destitute of hairs in the nectarine.
As to the nectarine, of its origin as a variation from the peach there is abundant evidence, as has already been mentioned; it is only requisite to add the very important fact that the seeds of the nectarine, even when that nectarine has been produced by bud-variation from a peach, will generally produce nectarines, or, as gardeners say, "come true."
There is no doubt about the latter variation, but with regard to its periodicity - that is, the number of years elapsing between one maximum and the next - much still remains to be done.
Not only so, but a similar variation was traced in the productivity of the great Lofoten (Lofoden) cod-fisheries.
Tracing, then, the quantities of oil given per 1,000 fish from year to year, they seemed to establish a connexion between the variation in " condition " of the fish, the variation in the inflow of Atlantic water, and the variation in the number of sunspots from year to year.
Detailed study of the cod shoals also showed that their composition was continually changing: in some years the shoal is composed of younger or older fish than the average and with this latter variation there are changes in the quantities of oil yielded per t,000 fish.
The temperature is, however, only an indirect cause of this variation and the direct cause is now known to be the activity of the nitrogen-bacteria.
At extreme dilution, when the ionization is complete, a variation in temperature cannot change its amount.
Thus as long as a moderate current flows, the only variation in the cell is the appearance of zinc sulphate in the liquid on the copper side of the porous wall.
Soc. (London, 1899); "On Geographical and Individual Variation in Mus sylvaticus and its Allies," op. cit.
when accompanying heroes, on the early painted vases; and thirdly, the type of her as produced by Pheidias, from which little variation appears to have been made.
The most careful determinations are affected by systematic errors arising from those diurnal and annual changes of temperature, the effect of which cannot be wholly eliminated in astronomical observation; and the recently discovered variation of latitude has introduced a new element of uncertainty into the determination.
Since then, two elaborate series of observations made with the zenith telescope for the purpose of determining the variation of latitude and the constant of aberration have been carried on by Professor C. L.
If however there is a small variation of the force in the space occupied by the body, it can be shown that the body will be urged, not necessarily towards a magnetic pole, but towards places of stronger magnetic force.
In the case of all the metals tested a small but measurable trace of magnetization remained after the so-called critical temperature had been exceeded; this decreased very slightly up to the highest temperature reached (1200°) without undergoing any such variation as had been suspected by Morris.
The Pantopoda are divided into three orders, the characters of which are dependent on variation in the presence of the full number of legs.
The calculus of variations lay undeveloped in Euler's mode of treating isoperimetrical problems. The fruitful method, again, of the variation of elements was introduced by Euler, but adopted and perfected by Lagrange, who first recognized its supreme importance to the analytical investigation of the planetary movements.
The final achievement of Lagrange in this direction was the extension of the method of the variation of arbitrary constants, successfully used by him in the investigation of periodical as well as of secular inequalities, to any system whatever of mutually interacting bodies.'
In the northern temperate zone we find forests of a single species, others of three or four species; in this great tropical forest the habit of growth is solitary and an acre of ground will contain hundreds of species - palms, myrtles, acacias, mimosas, cecropias, euphorbias, malvaceas, laurels, cedrellas, bignonias, bombaceas, apocyneas, malpigias, lecythises, swartzias, &c. The vegetation of the lower river-margins, which are periodically flooded, differs in some particulars from that of the higher ground, and the same variation is to be found between the forests of the upper and lower Amazon, and between the Amazon and its principal tributaries.
The sepals, which are generally free, show much variation in size, shape and covering, and afford valuable characters for the distinction of genera or sub-genera.
It was followed by a series of profound investigations, in which Lagrange and Laplace alternately surpassed and supplemented each other in assigning limits of variation to the several elements of the planetary orbits.
Later, the difficulty recurs in an acute form in reference to the continuous variation of a function.
(iv.) Variation is generally included in text-books on algebra, but apparently only because the reasoning is general.
a succession of numbers corresponding to the numbers I, 2, 3, ...) which possesses the property that, by starting far enough in the sequence, the range of variation of all subsequent terms can be made as small as we please, but (x+h) n always lies between the two values determining the range.
It is one of Darwin's great merits to have made use of these observations and to have formulated their results to a large extent as the laws of variation and heredity.
As the breeder selects a congenital variation which suits his requirements, and by breeding from the animals (or plants) exhibiting that variation obtains a new breed specially characterized by that variation, so in nature is there a selection amongst all the congenital variations of each generation of a species.
A useless " correlated variation " may have attained great volume and quality before it is (as, it were) seized upon and perfected by natural selection.
Thus Bionomics is treated in such articles as Evolution, Heredity, Variation, Mendelism, Reproduction, Sex, &C.; Zoo-dynamics under Medicine, Surgery, Physiology, Anatomy, Embryology, and allied articles; Plasmology under Cytology, Protoplasm, &C.; and Philosophical Zoology under numerous headings, Evolution, Biology, &C. See also Zoological Distribution, Palaeontology, Ocranography, Microtomy, &C.
In the branch of bionomics, however, concerned with the laws of variation and heredity (thremmatology), there has been considerable progress.
It does not, however, appear that " large " variations would thus be favoured any more than small ones, nor that the eliminating action of natural selection upon an unfavourable variation' could be checked.
It is no discovery that this latter kind of variation is not hereditable, and it is not the fact that the small variations, to which Darwin attached great but not exclusive importance as the material upon which natural selection operates, are of this latter kind.
The most instructive classification of the " variations " exhibited by fully formed organisms consists in the separation in the first place of those which arise from antecedent congenital, innate, constitutional or germinal variations from those which arise merely from the operation of variation of the environment or the food-supply upon normally constituted individuals.
An absolutely imperceptible physiological difference arising as a variation may be of selective value, and it may carry with it correlated variations which appeal to the human eye but are of no selective value themselves.
The views of de Vries and others as to the importance of " saltatory variation," the soundness of which was still by no means generally accepted in 1910, may be gathered from the articles Mendelismvi and Variation.
A due appreciation of the far-reaching results of " correlated variation " must, it appears, give a new and distinct explanation to the phenomena which are referred to as " large mutations," " discontinuous variation " and " saltatory evolution."
The analysis of the specific variations of organic form so as to determine what is really the nature and limitation of a single " character " or " individual variation," and whether two such true and strictly defined single variations of a single structural unit can actually " blend " when one is transmitted by the male parent and the other by the female parent, are matters which have yet to be determined.
The matter strictly relates to the consideration of the " causes of variation," and is as follows.
He pointed to the admitted fact of congenital variation, and he showed that congehital variations are arbitrary and, so to speak, non-significant.
Other mechanical disturbances may assist in this production of congenital variation.
In some cases a pair of animals pro- ‘ duce ten million offspring, and in such a number a large range of congenital variation is possible.
This newly discovered inheritance of " variation in the tendency to react " has a wide application and has led the present writer to coin the word " educability."
colour or form variation, happens to prove beneficial.
Further, it is evident that account must be taken of the variation of phase in estimating the magnitude of the effect at P of the first zone.
The same method of representation is applicable to spherical waves, issuing from a point, if the radius of curvature be large; for, although there is variation of phase along the length of the infinitesimal strip, the whole effect depends practically upon that of the central parts where the phase is sensibly constant.'
In physical chemistry he carried out many researches on the nature and process of solution, investigating in particular the thermal effects produced by the dilution of saline solutions, the variation of the specific heat of saline solutions with temperature and concentration, and the phenomena of liquid diffusion.
The details of the tradition of authorship show considerable variation; according to the Talmudic view Adam is author of the Sabbath psalm, xcii., and Melchizedek of Ps.
Marmosets are not larger than squirrels, and present great variation in colour; all have long tails, and many have the ears tufted.
A variation of a very few degrees in the blood itself produces death.
Variation, such as it was, consisted of a sleeveless dress covering From Hilprecht's Explorations in Bible Lands, by permission of A.
Lescot's edifice was reconstructed at the end of the 18th century by Bernard Poyet into the Fontaine des Innocents, this being a considerable variation of the original design.
Usually the cytoplasm shows a marked affinity for the acid stains, but the different bodies found in the cell may show great variation in their staining reactions.
Now differences in the amount of crystalloids cause alteration in osmotic pressure while the proteid content affects it but little; and of the crystalloids the chlorides appear to be those most liable to variation.
They contain nothing but meditative lyrical pieces, almost any one of which is typical of the whole, though there is considerable variation of merit.
But it was expressly st'.ced in a rubric that the old service of the mass was to proceed without variation of any rite or ceremony until after the priest had received the sacrament, that is, until long after the last of the three occasions for the use of incense explained above.
As a result of its relatively great depth there are seldom any great fluctuations of level in this lake due to wind disturbance, but the lake follows the general rule of the Great Lakes (q.v.) of seasonal and annual variation.
Bornemann re-examined all these results with great care, and gave formulae expressing the variation of the coefficients of discharge in different conditions (Civil Ingenieur, 1880).
A gas is a compressible fluid, and the change in volume is considerable with moderate variation of pressure.
Hence the space variation of the pressure in any direction, or the pressure-gradient, is the resolved force per unit volume in that direction.
With variation of temperature, the surfaces of equal pressure and density need not coincide; but, taking the pressure, density and temperature as connected by some relation,such as the gas-equation, the surfaces of equal density and temperature must intersect in lines lying on a surface of equal pressure.
To make this apparatus more perfectly automatic, an arrangement for continually adding to and mixing with the juice the proper proportion of milk of lime has been adapted to it; and although it may be objected that once the proportion has been determined no allowance is made for the variation in the quality of the juice coming from the mill owing to the variations that may occur in the canes fed into the mills, it is obviously as easy to vary the proportion with the automatic arrangement from time to time as it is to vary in each separate direction, if the man in charge will take the trouble to do so, which he very seldom does with the ordinary defecators, satisfying himself with testing the juice once or twice in a watch.
" It has long been known that proglottides of the same species often exhibit sporadic malformation from the normal shape, and the evidence goes to show that the variation was due to arrested growth or some unusual stress or pressure which, acting upon the young strobila, produced a deformation, and that the proglottides so affected could not regain their normal form.
There is great variation in size; the Malay "flying-fox" (Pteropus edulis) measures about a foot in the head and body, and has a wing-spread of 5 ft.; while in the smaller forms the head and body may be only about 2 in., and the wing-spread no more than a foot.
The variations are classified as: (1) Variation in type due to crossing, change of soil and climate, especially, for example, when seed from the tropics is introduced to temperate regions.
While these different feudal systems have shown a general similarity of organization, there has been also great variation in their details, because they have started from different institutions and developed in different ways.
It is easy to lose one's bearings by over-emphasizing the importance of variation and exception.
But too great emphasis upon variation conveys also a wrong impression.
of Aden, the summer heat is tempered by the monsoon winds, and the seasonal variation of temperature is less marked.
presents a third variation on the Messianic promise.
(4) Yet a fourth variation of the picture of the incoming of the Messianic deliverance is given in chap. xiv.
It is not yet experimentally proved that variation as the inverse square is absolutely true at all distances.
This variation is termed "distillation under reduced pressure or in a vacuum."
- The general observation that under a constant pressure a pure substance boils at a constant temperature leads to the conclusion that the distillate which comes over while the thermometer records only a small variation is of practically constant composition.
The above theory, coupled with such facts as the variation of the composition of the constant boiling-point fraction with the pressure under which the mixture is distilled, the proportionality of the density of all mixtures to their composition, &c., shows this to be erroneous.
It appears, however, that in this respect the habits of the different species show a certain amount of variation; thus, while G.
But the variation of the thermometer in winter and summer being considerableas much as 72 F.
On the other hand, the mean daily variation is in general less than that in other countries having the same latitude: it is greatest in January, when it reaches i8 F., and least in July, when it barely exceeds 9 F.
The monthly variation is very great in March, when it usually reaches 43 F.
This, which has long been recognized as a class-reaction, is obviously capable of endless variation.
As to the variation of name, Defoe or Foe, its owner signed either indifferently till late in life, and where his initials occur they are sometimes D.
amplus, large), in astronomy, the angular distance of the rising or setting sun, or other heavenly body, from the east or west point of the horizon; used mostly by navigators in finding the variation of the compass by the setting sun.
They can adapt their motions to every variation of the ground over which they move, yet all varieties of snake locomotion are founded on the following simple process.
- Our information as to the oracle at Delphi and the manner in which it was consulted is somewhat confused; there probably was considerable variation at different periods.
The details of the structure of the flower show a wide variation; the flowers are often extremely simple, sometimes as in Arum, reduced to a single stamen or pistil.
This variation, however, is not always linear.
In some cases there is a very sudden drop at or below a certain temperature to a much lower value, and above and below the point the temperature variation is small.
There are very few substances, however, for which the optical refractive index has the same value as K for steady or slowly varying electric force, on account of the great variation of the value of K with frequency.
Though all yield fur of serviceable quality, the commercial value varies immensely, not only according to the species from which it is obtained, but according to individual variation, depending upon age, sex, season, and other circumstances.
which is useful for calculating the variation of the specific heat s with variation of density at constant temperature.
A similar expression for the variation of the specific heat S at constant pressure is obtained from the second expression in (8), by taking p and 0 as independent variables; but it follows more directly from a consideration of the variation of the function (E+pv).
Since dE=dH - pdv, we have evidently for the variation of the total heat from the second expression (8), dF=d(E + pv) =dH+vdp=Sde - (Odv/de - v)dp .
(I I) This expression shows that the rate of variation of the total heat with temperature at constant pressure is equal to the specific heat at constant pressure.
Observing that F is a function of the co-ordinates expressing the state of the substance, we obtain for the variation of S with pressure at constant temperature, dS/dp (0 const) '=' 2 F/dedp =-0d 2 v/d0 2 (p const) (12) If the heat supplied to a substance which is expanding reversibly and doing external work, pdv, is equal to the external work done, the intrinsic energy, E, remains constant.
This coefficient is sometimes called the " angular coefficient," and may be regarded as a measure of the deviations from Boyle's law, 'which may be most simply expressed at moderate pressures by formulating the variation of the angular coefficient with temperature.
Soc., 1900) on steam confirm this type of equation, but give much larger values of the cooling effect than for C02, and a more rapid rate of variation with temperature.
..) In order to deduce the complete variation of the specific heats from these equations, it is necessary to make some assumption with regard to the variation of the specific heats with temperature.
The values of the corresponding functions for the liquid or solid cannot be accurately expressed, as the theoretical variation of the specific heat is unknown, but if we take the specific heat at constant pressure s to be approximately constant, and observe the small residual variation dh of the total heat, we may write F'=s'D+dh+B'.
With regard to the degree in which this armature is developed, not only do the species differ from each other, but almost every species shows an extraordinary amount of variation.
There is a wide variation of climate for so small a territory, the higher elevations of the Sierra de Ajusco being cold and humid (the Mexican Central crosses the range at an elevation of 9974 ft.); the lower spurs mild, temperate and healthy, the lower valleys subtropical, hot and unhealthy.
Dr Leith-Adams, working from more abundant materials, has shown that the number of ridges of each tooth, especially those at the posterior end of the series, is subject to individual variation, ranging in each tooth of the series within the following limits: 3 to 4, 6 to 9, 9 to 12, 9 to 15, 14 to 16, 18 to 27 - excluding the small plates, called " talons," at each end.
No better example could be found of the almost limitless variation in so-called species.
Precision, which was at first unattainable for want of an epoch, was afterwards no less unattainable from the multiplicity, and sometimes the variation, of epochs.
The general characters of the jaws have been mentioned above, and in detail there is great variation in these organs among the different families.
The chief errors to which the stereometer is liable are (I) variation of temperature and atmospheric pressure during the experiment, and (2) the presence of moisture which disturbs Boyle's law.
The adventures of Blanchefleur, wife of Charlemagne, form a variation of the common tale of the innocent wife falsely accused, and are told in Macaire and in the extant fragments of La Reine Sibille (14th century).
Oros, sun, and Ã†Tpov, a measure), an instrument originally designed for measuring the variation of the sun's diameter at different seasons of the year, but applied now to the modern form of the instrument which is capable of much wider use.
The composition of the ashes of different coals is subject to considerable variation, as will be seen by Table II.
As the former are only active in the air while the latter are anaerobic, the activity of either agent is conditioned by variation in the water level of the bog.
The variation in the composition of coal seams in different parts of the same basin is a difficult matter to explain.
As regards the duration of British coal resources, the commissioners reported (1905): " This question turns chiefly upon the maintenance or the variation of the annual output.
To maintain e µe constant, compensation for variation of µ is made by inversely varying 0.
In this way the brake may be arranged to maintain a constant torque, notwithstanding variation of the speed.
They are both reddish yellow and brownish black (according to individual variation) in skin colour, with head hair often tending to russet, and body hair of two kinds - black and bristly on the upper lip, chin, chest, axillae and pubes; and yellowish and fleecy on the cheeks, back and limbs.
Considering the really few colours that the birds exhibit, the variation is something marvellous, so that fifty examples may be compared without finding a very close resemblance between any two of them, while the individual variation is increased by the "eartufts," which generally differ in colour from the frill.
But it is important to notice that a parallel story (xx.) is without this distinctively Philistine background, and this variation is significant.
Some foresights have, however, a lateral motion giving within narrow limits the deflection found to be necessary for the variation of each rifle from the average.
Regnault, from analyses of the air of Paris, obtained a variation of 20 999 to 20 913; country air varied from 20.903 to 21.000; while air taken from over the sea showed an extreme variation of 20 940 to 20 850.
The great majority of antelopes, exclusive of the doubtful chamois group (which, however, will be included in the present article), are African, although the gazelles are to a considerable extent an Asiatic;'group. They include ruminants varying in size from a hare to an ox; and comprise about 150 species, although this number is subject to considerable variation according to personal views as to the limitations of species and races.
6), and the brindled gnu, or blue wildebeest (C. taurinus), which, with some local variation, has a large range in South and East Africa.
It is, moreover, interesting to observe how slight an amount of variation has taken place in forms isolated during such an enormous time.
The treatment of an angle as generated by rotation, the investigation of the relations between trigonometrical ratios and circular measure, the application of interpolation to trigonometrical tables, and the general use of graphical methods to represent continuous variation, all imply an analytical onlook, and must therefore be deferred to this stage.
39 The plane figures with which we are concerned come mainly under the description of graphs of continuous variation.
Soc., 1874, 22, p. 53 1) first pointed out that refraction would result from a variation in the temperature of the air at different heights.
Stokes showed that this effect is one of refraction, due to variation of velocity of the air from the surface upwards Brit.
§ 311) gives the pressure variations in the incident waves in terms of those in the resonator, and so the pressure variation and the amplitude of vibration in the waves to be measured were determined.
The approximate theory of pipes due to Bernoulli assumes a loop at the open end, but the condition for a loop at the open end, that of no pressure variation, cannot be exactly fulfilled.
It may be noted that in practice there is another reason for pressure variation at the end of the pipe.
Formerly it was generally supposed that the Tartini tone was due to the beats themselves, that the mere variation in the amplitude was equivalent, as far as the ear is concerned, to a superposition on the two original tones of a smooth sine displacement of the same periodicity as that variation.
This want of proportionality will have a periodicity, that of the impinging waves, and so will produce vibrations just as does the variation of pressure in the case last investigated.
The semi-elliptical shape of the arches, the variation of span, the _ slight curvature of the 26:0'=-----.
In Europe a variation of temperature of 70° C. or 126° F.
Baker and others, show that the breaking stress of a bar is not a fixed quantity, but depends on the range of variation of stress to which it is subjected, if that variation is repeated a very large number of times.
The real nature of the action is not well understood, but the word fatigue may be used, if it is not considered to imply more than that the breaking stress under repetition of loading diminishes as the range of variation increases.
Ricks, "On the Variation of the Constants of Electricity Supply Meters, with Temperature and Current," Electrician (1897), 39, 573.
An idea as to the advance made by this method is recorded in the variation in the price of calcium.
7th century, A.D., the variation Genua (which has led to great confusion with Genoa) being also found in the 6th century.
Later still he engaged in the study of the relations between chemical constitution and rotation of the plane of polarization in a magnetic field, and enunciated a law expressing the variation of such rotation in bodies belonging to homologous series.
This innate power of variation has enabled the florist to obtain, and ultimately to "fix," so many remarkable varieties.
(The colour variation in the flowers of seedlings is discussed above.) Seeds are sown in.
The principal causes of variation in the individual are age, period of lactation, nature and amount of food, state of health, and treatment, such as frequency of milking, &c. The following table indicates the The average quantity of milk yielded by variable, both in individuals and breeds.
S., 18 77): but this method requires n to be known with accuracy, as I% variation in n causes more than 1% variation in tan n.
In the Weston standard cell cadmium and cadmium sulphate are substituted for zinc and zinc sulphate; it has the advantage of a much smaller coefficient of temperature variation than the Clark cell.
When so made, the cell has an electromotive force of 1.072 volts and no sensible temperature variation.
More important are those passages in which the Massoretes have definitely adopted a variation from the consonantal text.
28 a later epistles are really the work of St Paul, the difference must be accounted for (a) by a somewhat unusual range of variation in style and thought on his part, and (b) by different environment and different purpose.
The first missionary journey may have begun in 47 or 48; the arrival of Festus may have taken place in the summer of 58 or of 59; the two years of the Roman imprisonment recorded in the last chapter of Acts may have ended in the spring of 61 or 62; and the dates which fall in between these extremes are liable to the same variation.
In the San Jose plateau (3000-5000 ft.), which is the most densely populated portion of the temperate zone, the average is 68°, with an average variation for all seasons of only 5°.
But the limbs show with regard to development great variation, and an uninterrupted transition from the most perfect condition of two pairs with five separate clawed toes to their total disappearance; yet even limbless lizards retain bony vestiges beneath the skin.
In the verification of a precise standard of length there may be taken into account the influence of the variation of atmospheric pressure.
(76 millimetres), which denotes a variation of 103 grammes per square centimetre in the pressure of the atmosphere, the change caused thereby in the length of a standard of linear measurement would appear to be as follows: --
is caused by the variation of atmospheric pressure from 28 to 31 in.
3, below, the difference in length for a variation of 76 mm.
1: Limits of Variation in Different Copies, Places and Times.
Covering a longer time, we find an average variation of 1/200 in the Attic foot (25), 1/150 in the English foot (25), 1/170 in the English itinerary foot (25).
So we may say that an average variation of 1/400 by toleration, extending to double that by change of place and time, is usual in ancient measures.
In weights of the same place and age there is a far wider range; at Defenneh (29), within a century probably, the average variation of different units is 1/36, 1/60, and 1/67, the range being just the same as in all times and places taken together.
Even in a set of weights all found together, the average variation is only reduced to 1/60 in place of 1/36 (29).
Taking a wider range of place and time, the Roman libra has an average variation of 1/50 in the examples of better period (43), and in those of Byzantine age 1/35 (44).
Average variation may be said to range from 1/40 to 1/70 in different units, doubtless greatly due to defective balances.
2: Rate of Variation.
-- Though large differences may exist, the rate of general variation is but slow -- excluding, of course, all monetary standards.
3: Tendency of Variation -- This is, in the above cases of lengths, to an increase in course of time.
4: Details of Variation -- Having noticed variation in the gross, we must next observe its details.
Hence we see that if one unit is derived from another it may be possible, by the similarity or difference of the forms of the curves, to discern whether it was derived by general consent and recognition from a standard in the same condition of distribution as that in which we know it, or whether it was derived from it in earlier times before it became so varied, or by some one action forming it from an individual example of the other standard without any variation being transmitted.
In Greece it is the most usual unit, occurring in the Propylaea at Athens 12.44, temple at Aegina 12.40, Miletus 12.51, the Olympic course 12.62, &c. (18); thirteen buildings giving an average of 12.45, mean variation .06 (25), = (3/5)ths of 20.75, m.
A variation on the main system was made by forming a mina of 50 shekels.
The same circumstances detertnine the variation of profits, but in an opposite direction; the increase of stock, which raises wages, tending to lower profit through the mutual competition of capitalists.
Towards the head and on the limbs the spots tend to become solid, but there is great local variation in regard to their form and arrangement.
The rapid variation of certain groups of animals or the acceleration of certain organs is also not evidence of the sudden appearance of new adaptive characters.
Little proof is afforded among the mammals of extinction through arrested evolution or through the limiting of variation, although such laws undoubtedly exist.
They also exhibit a variation from the characteristic dualism of Gnosticism into monism, in their conception of the fall of Sophia and their derivation of matter from the passions of the fallen Sophia.
The sodium vapour in the middle is very dense on the heated side, the density diminishing rapidly towards the upper part of the tube, so that, although not prismatic in form, it refracts like a prism owing to the variation in density.
Trypanosomes vary greatly with regard to size; even in one and the same species this variation is often noticeable, especially under.
Among his happy conjectures may be mentioned that of the sun's axial rotation, postulated by him as the physical cause of the revolutions of the planets, and soon after confirmed by the discovery of sun-spots; the suggestion of a periodical variation in the obliquity of the ecliptic; and the explanation as a solar atmospheric effect of the radiance observed to surround the totally eclipsed sun.
There is, however, considerable local variation both in the matter of size and of colour from the typical coyote of Iowa, which measures about 50 in.
The countrys centre of population in 110 years moved more than 5oo m westward, almost exactly along the 39th parallel of latitude: 9.5 degrees of longitude, with an extreme variation.
In the third group women greatly preponderate in the occupation of stenographers and type-writers; and in those of book-keepers and accountants, clerks and copyists, packers and shippers, saleswomen (which is the largest class), and telegraph and telephone operators they have a large representation (13 to 34 ~ A great Variation exists in the proportion of the sexes employed in different manufacturing industries.
His first contribution 3 was a variation of the method of Archimedes.
A further variation consists in the development of additional shelly plates upon the dorsal line between the two large valves (Pholadidae).
This Long Period, However, May Be Reduced To Four Hundred Years; For Since The Dominical Letter Goes Back Five Places Every Four Years, Its Variation In Four Hundred Years, In The Julian Calendar, Was Five Hundred Places, Which Is Equivalent To Only Three Places (For Five Hundred Divided By Seven Leaves Three); But The Gregorian Calendar Suppresses Exactly Three Intercalations In Four Hundred Years, So That After Four Hundred Years The Dominical Letters Must Again Return In The Same Order.
Both vertically and transversely it measures about an inch and a quarter, while antero-posteriorly it is only about three-quarters of an inch, though its size is liable to great variation.
But it is clear that if we increase A, the sectional area of the stem, we shall diminish 1, the length of a scale-division corresponding to a given variation of density, and thereby proportionately diminish the sensibility of the instrument, while diminishing the section A will increase land proportionately increase the sensibility, but will diminish the range over which the instrument can be employed.
The genus which is common to the northern parts of both hemispheres is distinguished by the large cheek-pouches and by the absence or rudimentary condition of the claw of the first hind-toe, resembles Tamias in the slender form of the body, but displays great variation in the length of the tail, which may be a mere stump, or comparatively long.
(b) With reference to raw and thrown silk, in order to enable the count to show the degrees of variation incidental to this class of material, it was decided for a basis of a fixed length and variable count weight.
The oscillation of the earth's axis may arise in two distinct ways; distinguished as " nutation of the axis " and " variation of latitude.
the north and south poles occupy permanent geographical positions, yet the axis is not directed towards a fixed point in the heavens; variation of latitude, however, is associated with the shifting of the axis within the earth, i.e.
The rapid variation in the intensity of the magnetic field causes a brilliant electrodeless discharge which is seen in the form of a ring passing near the inner walls of the bulb when the pressure is properly adjusted.
The Litany, for example, in the Prayer Book is based upon the medieval Latin Litany, but great variation both in substance and language and by way of addition and omission, are made in it.
Lutheran influence can likewise be traced in way of variation introduced into the baptismal and other sacramental or occasional offices.
As a result of their isolation, the proportion of endemic plants is greater here than in any other region, and the great elevation of the mountains, with the consequent variation in temperature, moisture and barometric pressure, has multiplied the number of species.
(b) He contends that, when matter ascends to the evolution of organic life, the unconscious has a power, over and above its atomic volitions, of introducing a new element, and that in consequence the facts of variation, selection and inheritance, pointed out by Darwin, are merely means which the unconscious uses for its own ends in morphological development.
By thus supposing a psychical basis to evolution, Fechner, anticipating Wundt, substituted a psychical development of organs for Darwinian accidental variation.
Examples are subject to much variation in colour and shade, and in some the lower parts are deeply tinged with yellow.
meridian, called the magnetic variation or declination; amongst mariners this angle is known as the variation of the compass.
In the usual navigable waters of the world the variation alters from 30° to the east to 45° to the west of the geographical meridian, being westerly in the Atlantic and Indian oceans, easterly in the Pacific. The vertical plane passing through the longitudinal axis of such a needle is known as the magnetic meridian.
Following the first chart of lines of equal variation compiled by Edmund Halley in 1700, charts of similar type have been published from time to time embodying recent observations and corrected for the secular change, thus providing seamen with values of the variation accurate to about 30' of arc. Possessing these data, it is easy to ascertain by observation the effects of the iron in a ship in disturbing the compass, and it will be found for the most part in every vessel that the needle is deflected from the magnetic meridian by a horizontal angle called the deviation of the compass; in some directions of the ship's head adding to the known variation of the place, in other directions subtracting from it.
in which the ship is steering and the north point of the compass or course is at once seen; and if the magnetic variation and the disturbing effects of the ship's iron are known, the desired angle between the ships's course and the geographical meridian can be computed.
It is also provided with an azimuth circle or mirror and a shadow pin or style placed in the centre of the glass cover, by either of which the variable angle between the compass north and true north, called the "total error," or variation and deviation combined, can be observed.
ii.) that the abnormal values of the variation observed in the wood-built ships of his day was due to deviation of the compass caused by the iron in the ship; that the deviation was zero when the ship's head was near the north and south points; that it attained its maximum on the east and west points, and varied as the sine of the azimuth of the ship's head reckoned from the zero points.
"The sphere of Chinese navigation," he tells us (p. 447), "is too limited to have afforded experience and observation for forming any system of laws supposed to govern the variation of the needle..
In the Leiden MS. of this work, which for long was erroneously ascribed to one Peter Adsiger, is a spurious passage, long believed to mention the variation of the compass.
It has since been discovered, however, that the magnitude of the acceleration in question is not exactly the same at different places on the earth, the range of variation amounting to about 2%.
He attained correct views as to the character of centrifugal force in connexion with Galileo's theory; and, when the fact of the variation of gravity (Galileo's acceleration) in different latitudes first became known from the results of pendulum experiments, he at once perceived the possibility of connecting such a variation with the fact of the earth's diurnal rotation relatively to the stars.
This represents about two-thirds of the total variation of Galileo's acceleration between the equator and the poles, the balance being due to the ellipticity of the figure of the earth.
In all the cases hitherto considered, the liquid phase alone has been capable of continuous variation in composition.
The reasoning given above is independent of the temperature, so that the variation with temperature of the osmotic pressure of a dilute solution must be the same as that of a gas, while Boyle's law must equally apply to both systems. Experimental evidence confirms these results, and extends them to the cases of non-volatile solutes - as is, indeed, to be expected, since volatility is merely a matter of degree.
Callendar has shown that the variation of vapour pressure of a solution with pressure is given by the expression V'dP = vdp, where V' is the change in volume of the solution when unit mass of solvent is mixed with it.
The probable error in neglecting any variation of specific heat is small, and we may calculate L from the values of Lo - (s - s') (To - T), where s - s' is about 0.5 calories.
The variation of L with pressure is probably small.
The variation of gases from Boyle's law is represented in the equation of Van der Waals by subtracting a constant b from the total volume to represent the effect of the volume of the molecules themselves.
proportional to the rate of variation - dc/dx of the concentration c with the distance x, so that the number of gramme-molecules of solute which, in a time dt, cross an area A of a long cylinder of constant cross section is dN = - DA(dc/dx)dt, where D is a constant known as the diffusion constant or the diffusivity.
The above arrangements are found with scarcely any variation in all the charter-houses of western Europe.
The condition of albinism thus assumed as a seasonal variation is never complete, for the eyes at least retain their pigmented state.
I and 2; Charles Darwin, Variation of Animals and Plants under Domestication, vols.
Vernon, Variation in Animals and Plants (London, 1903); F.
The variegated plumage of the Snipe is subject to no inconsiderable variation, especially in the extent of dark markings on the belly, flanks, and axillaries, while examples are occasionally seen in which no trace of white, and hardly any of buff or grey, is visible, the place of these tints being taken by several shades of chocolate-brown.
2 In a series of writings, however, extending over so long a period as those of the Old Testament, some variation or development in language is to be expected apart from the natural differences between the poetic (or prophetic) and prose styles.
The second of these essays opens with the striking remark, "There can scarcely be a doubt entertained respecting the reducibility of all elastic fluids of whatever kind, into liquids; and we ought not to despair of effecting it in low temperatures and by strong pressures exerted upon the unmixed gases"; further, after describing experiments to ascertain the tension of aqueous vapour at different points between 32° and 212° F., he concludes, from observations on the vapour of six different liquids, "that the variation of the force of vapour from all liquids is the same for the same variation of temperature, reckoning from vapour of any given force."
This unusual variation probably arises from early differences of opinion as to whether there was one Mark or more than one.
The combination of the two, however, shows clearly that, without much variation of heat or loss of light, any extent of space may be covered, and houses of any altitude constructed.
The colour of the fruit varies from green to deep purple, the size from that of a small cherry to that of a hen's egg; the form is oblong acute or obtuse at both ends, or globular; the stones or kernels vary in like manner; and the flavour, season of ripening and duration are all subject to variation.
to perpetual variation owing, on the one hand, to the erosion of the coasts, and, on the other, to reclamation of land by means of endiking and drainage operations.
All commercial iron and steel contain more or less of both these impurities, the influence of which is so strong that a variation of o o, %, i.e.
On its way from the blast furnace to the converter or open hearth furnace the pig iron is often passed through a great reservoir called a " mixer," which acts also as an equalizer, to lessen the variation in composition of the cast iron, and as a purifier, removing part of the sulphur and silicon.
The vowel i could become e as de = di, &c. Consonantal variation is most common.
Fox, Common.-The variation of size and quality is considerable, and the colour is anything from grey to red.
The underwool in all sorts is generally of a bluish-grey tone, but the top hair in the depth of winter is usually full enough in quantity to, hide any such variation.
3), while their plungers are connected to a disk crank which rotates above the point 0, which is the centre of the main crank; 0 S being the crank length or half stroke of the engine, any variation in its length will vary the power of the engine and at the same time the quantity of water used.
Pelton wheels are very sensitive to variation of load, and considerable trouble was experienced at first in securing adequate A s has now become one of 5.
The emigration of Belgians from their country is small and reveals little variation.
From certain differences in the striping of the legs, as well as from variation in skull-characters, the existence of more than a single species has been suggested; but further evidence is required before such a view can be definitely accepted.
The true name of the book appears in the authorities in a variety of forms, the variation affecting both the author's name and the description of his book.
(- - A variation of the tube method, which can be applied to metals and good con ductors, depends on the employment of a thick cylinder with a small axial hole in place of a thin tube.
Tait repeated Forbes's experiments, using one of the same iron bars, and endeavoured to correct his results for the variation of the specific heat c. J.
The variation of c is uncertain.
Since both k and c are generally variable with the temperature, and the mode of variation of either is often unknown, the results of these methods are generally less certain with regard to the actual Carves showing Cie farzalaon of Temperature wilki FIG.
This can be measured graphically without any knowledge of the law of variation of the surface temperature, or of the laws of propagation of heat waves.
To illustrate the main features of the calculation, we may suppose that the surface is subject to a simple-harmonic cycle of temperature variation, so that the temperature at any time t is given by an equation of the form 0 - 0 0 = Asin 27rnt= A sin 27rt/T, (5) where 0 0 is the mean temperature of the surface, A the amplitude of the cycle, n the frequency, and T the period.
4 is o 60 in., at which depth the amplitude of the variation is reduced to less than one five-hundredth part (e 2 7r) of that at the surface, so that for all practical purposes the oscillation may be neglected beyond one wave-length At half a wave-length the amplitude is only 3 rd of that at the surface.
Angstrom endeavoured to find the variation of conductivity by this method, but he assumed c to be the same for two different bars, and made no allowance for its variation with temperature.
He thus found nearly the same rate of variation for the thermal as for the electric conductivity.
Ang3trom's value for iron, when corrected for obvious numerical errors, and for the probable variation of c, becomes Iron, k =0.164 (1-0.0013 0), but this is very doubtful as c was not measured.
The variation of c was determined by a special series of experiments.
No allowance was made for the variation of density with temperature, or for the variation of the distance between the thermometers, owing to the expansion of the bar.
If the current C is chosen so that C 2 R ° a = hpl, the external heat-loss is compensated by the variation of resistance with temperature.
Neglecting the external heat-loss, and the variation of the thermal and electric conductivities k and k', we obtain, as before, for the difference of temperature between the centre and ends, the equation O, Tho z Go = C 2 R1/8qk = ECl/8qk = E 2 k'/8k, (11) where E is the difference of electric potential between the ends.
Moreover, the variation of thermal conductivity with temperature is small and uncertain, whereas the variation of electrical conductivity is large and can be accurately determined, and may therefore be legitimately utilized for eliminating the external heat-loss.
This, at first sight, paradoxical result is explained by the fact that the mean free path of each molecule increases in the same proportion as the density is diminished, so that as the number of molecules crossing each square centimetre decreases, the distance to which each carries its momentum increases, and the total transfer of momentum is unaffected by variation of density.
The question of the variation of conductivity with temperature is more difficult.
In some cases this variation is comparatively little.
Amongst causes of variation in the quantity of water needed will be its quality and temperature and rate of flow, the climate, the season, the soil, the subsoil, the artificial drainage, the slope, the aspect and the crop. In actual practice the amount of water varies from 300 gallons per acre in the hour to no less than 28,000 gallons.
the other in others) and titles, we found without variation the same treatise, beginning, I, Clement, &c."
shows the annual variation observed in the frequency of aurora.
If sunlight and twilight were the sole cause of the apparent annual variation, the frequency would have a simple period, with a maximum at midwinter and a minimum at midsummer.
It is only during winter and in high latitudes that we can hope to ascertain anything directly as to the real diurnal variation of the causes whose influence is visible at night as aurora.
- Diurnal Variation.
The preceding remarks relate to auroras as a whole; the different forms differ considerably in their diurnal variation.
At most places the variation in the frequency has shown a general similarity to that of sun-spots.
points changes rapidly with change of latitude and longitude, and has a large diurnal variation.
The variation throughout the twenty-four hours in the percentage seen in the south was as follows: - The mean from the whole twenty-four hours is sixty-three.
Between the two extremes there was variation not only between city and city, but, no doubt, in one and the same city at different times.
Hecker in his measurement of the variation in the vertical and of tidal earth tremors.
There is evidence that the amount of stress on syllables, and the consequent length of vowels, varied greatly in spoken Coptic, and that the variation gave much trouble to the scribes; the early Christian writers must have taken as a model for each dialect the deliberate speech of grave elders or preachers, and so secured a uniform system of accentuation.
showing the variation of periods and essentials of o style; and this is followed ft by an account of the use made of material products, (U ms of the tools and instru ments employed, and of the monuments.
The base of the pyramid of Snefru had an average variation of 6 in.
But, immediately after, Cheops improved on this with a variation of less than 6 in.
Chephren fell off, having I~5 error on 8475, and 33 of variation.; and Mycerinus (Menkeur) had 3 in.
erroron 4154 and I50 variation of direction (P.M.
Of perhaps later date the two south pyramids of Dahshur show errors of 37 on 7459 and II on 2065 in., and variation of direction of 4 and 10 (P.S.
Apart from the literary characteristics which clearly differentiate this narrative from the preceding accounts of J and E, the following points of variation are worthy of consideration: (I) The people refuse to listen to Moses; (2) Aaron is appointed to be Moses' spokesman, not with the people, but with Pharaoh; (3) one sign is given (not three) and performed before Pharaoh; (4) the rod is turned into a reptile (tannin), not a serpent (n(thash).
Apart from the omissions the most striking difference between the two sections is the variation in order, the different sections of ch.
For this version exhibits numerous cases of variation, both as regards order and contents, from the Hebrew text; moreover the translation, more particularly of many technical terms, differs from that of ch.
In colour different specimens present a considerable range of variation, but the animal is ordinarily of a rich dark brown, scarcely or not paler below than on the general upper parts; but the back xviii.
It may be considered as arising from a semi-annual variation in the eccentricity of the moon's orbit and the position of its perigee.
The species is subject to great racial variation.
On extending his inquiry to other aelotropic crystals he observed a similar variation, and was thus led, in 1825, to the discovery that aelotropic crystals, when heated, expand unequally in the direction of dissimilar axes.
There is, however, considerable variation in the nature of the membrane in different species; thus the cell-wall of Oedogonium, treated with sulphuric acid and iodine, turns a bright blue, while the colour is very faint in the case of Spirogyra, the wall of which is said to consist for the most part of pectose.
The two were to perform a new variation upon the theme of Abelard and HeloIse.
In the progress of this erosion full scope has been afforded for the modification of form by variation in geological structure.
VARIATION AND SELECTION, in biology.
Erasmus Darwin, the grandfather of Charles Darwin, set forth ',in' Zoonomia a much more definite theory of the relation of variation to evolution, and the following passage, cited by Clodd, clearly expresses it: "When we revolve in our minds the metamorphoses of animals, as from the tadpole to the frog; secondly, the changes produced by artificial cultivation, as in the breeds of horses, dogs and sheep; thirdly, the changes produced by conditions of climate and season, as in the sheep of warm climates being covered with hair instead of wool, and the hares and partridges of northern climates becoming white in winter; when, further, we observe the changes of structure produced by habit, as shewn especially by men of different occupations; or the changes produced by artificial mutilation and prenatal influences, as in the crossing of species and production of monsters; fourth, when we observe the essential unity of plan in all warmblooded animals - we are led to conclude that they have been alike produced from a single living filament."
Treviranus, in the beginning of the 10th century, laid stress on the indefiniteness of variation, but assumed that some of it was adaptive response to the environment, and some due to sexual crossing.
Variation was in fact a purposive response.
St Hilaire and afterwards his son Isodore regarded variation as not indefinite but directly evoked by the demands of the environment.
Schleiden regarded variation and the production of new or improved structures as an unfolding of possibilities latent in the stock.
Robert Chambers, in the once famous Vestiges of Creation, interested and shocked his contemporaries by his denial of the fixity of species and his insistence on creation by progressive evolution, but had no better theory of the cause of variation than to suppose that organisms - "from the simplest and oldest to the highest and most recent" were possessed of "an inherent impulse, imparted by the Almighty both to advance them from the several grades and modify their structure as circumstances required."
Although the pre-Darwinian writers amongst them invoked nearly every principle that Darwin or his successors have suggested, they failed to carry conviction with regard to evolution, and they neither propounded a coherent philosophy of variation nor suggested a mechanism by which variations that appeared might give rise to new species.
He did not suggest that every variation and every character must have a "selection value," although he pointed out that, because of our ignorance of animal physiology, it was extremely rash to set down any characters as valueless to their owners.
It is even more important to notice that he did not suggest that every individual with a favourable variation must be selected, or that the selected or favoured animals were better or higher, but merely that they were more adapted to their surroundings.