Gives some data as to the variability of thunder from year to year.
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.
It was difficult to be sure as to the variations in the actual number of fish caught, but it was easy to show that there was a real variability in the yield of cod-liver oil (an important product of the fishery).
In both cases no extraneous cause can be assigned; the period seems to be inherent in the star itself and not to be determined by the revolution of a satellite (no variability of the line-of-sight motion of Mira has been found, so that it is probably not accompanied by any large companion).
The Aristotelian would find no difficulty in such a variability; it is only the disciple of Dalton to whom it seems impossible.
When we consider, however, the great variability in those surroundings and the consequent changes a plant must encounter, it appears obvious that interaction ~nd adjustment between the plant and its environment must be constant and well balanced.
A transformation which is sometimes rapid, sometimes slow, but always continuous, is wrought by the reciprocal action of the innate variability of plants and of the variability of the external factors.
He proclaimed the variability of species in opposition to the views of Linnaeus as to their fixity, and moreover supposed that this variability arose in part by degradation.
The conclusions deducible from their anthropological features - apart from the general difficulty of arriving at safe conclusions on this ground alone, on account of the variability of the ethnological type under various conditions of life - are also rather indefinite.
Later still Hjort showed that the study of the variability in the productivity of a fishery is always a complex matter - far more so than was formerly supposed.
Thus the field of disease arising not from essential defect in the body, but from external contingencies, is vastly enlarging; while on the other hand the great variability of individuals in susceptibility explains the very variable results of such extrinsic causes.
In modern thermometry instruments of extreme accuracy are required, and researches have been made, especially in Germany and France, to ascertain the causes of variability in mercurial thermometers, and how such variability is to be removed or reduced.
Other tests show variability in burning quality, elasticity of leaf, texture, taste, &c. The United States Department of Agriculture has closely investigated this important question and the results attained are brought together by Messrs H.
Both in size and form considerable variability is displayed, the species of Holochilus being some of the largest, while the common white-footed mouse (Eligmodon leucopus) of North America is one of the smaller forms. Some kinds, such as Oryzomys and Peromyscus have long, rat-like tails, while others, like Acodon, are short-tailed and more volelike in appearance.
Deperet notes that the genus Neumayria, an ammonite of the Kimmeridgian, suddenly branches out into an explosion" of forms. Deperet also observes the contrast between periods of quiescence and limited variability and periods of sudden efflorescence.
Among the ammonites the loss of power to coil the shell is one feature of racial old age, and in others old age is accompanied by closer coiling and loss of surface ornamentation, such as spines, ribs, spirals; while in other forms an arresting of variability precedes extinction.
The tongue presents little variability in length, being short and compressed, with a blunt tip, which is never protruded beyond the incisors.
To explain this great variability of spectroscopic effects we may either adopt the view that molecular aggregates of semi-stable nature may be found in vacuum tubes, or that a molecule may gain or lose one or more additional electrons and thus form new vibrating systems. It seemed that an important guide to clear our notions in this direction could be obtained through the discovery of J.
This curious variability, deserving more attention than it has yet received, only occurs in the outer feathers of the series, which are narrow in form and extremely stiff, there being always 10 in the middle of ordinary breadth.
It is to the different characters of the stations they occupy with respect to exposure, moisture, &c., that the variability observed in many types of lichens is to be attributed.
He insisted that the great powers of increase of all organisms led to a tremendous struggle for existence, and that variability extended to every part and organ of every organism; that the variability was large in amount in proportion to the size of the part affected, and occurred in a considerable proportion of the individuals of those large and dominant species which might be supposed to be breaking up into new species.
The variability of structures which are repeated in the body of the same individual (serial homologues) has been studied by Pearson and his pupils with important results.
Measure of the individual variability of the organism which produces them.
We see therefore that while leaves, gathered in equal numbers from each of loo trees, are distributed about their mean with a standard deviation of 1.735 veins, the leaves gathered from a single tree are distributed about their mean with a standard deviation of 1.426 veins, the ratio between variability of the race and variability of the individual tree being 1 - (0-5699)1=0.822.
We may therefore conclude that for large classes of characters, both animal and vegetable, the variability of an individual, as measured by the standard deviation of its undifferentiated but repeated organs, is a constant fraction of the variability of its race, as measured by the standard deviation of the corresponding series of organs produced by all the individuals of its race.
The evidence that the correlation between sexually produced brethren is the same as that existing between the asexually repeated organs on an individual body renders it impossible to accept Weismann's view that one of the results produced by the differentiation of animals and plants into two sexes is an increase in the variability of their offspring.
The question of a possible variability in the length of the day is one of fundamental importance.
There is some over-lapping of these two classes as regards length of period, and it is doubtful in which class some stars, whose periods are between io days and 150 days, should be placed; but the two classes are quite distinct physically, and the variability depends on entirely different causes.
The variability of Algol ((3 Persei) was discovered in 1783 by John Goodricke (1764-1786), but, judging from its name, which signifies ' ` the demon," it seems possible that its peculiarity may have been known to the ancient astronomers.
Ever since the variability of Algol was observed it was suspected to be due to a partial eclipse of the star by a dark body nearly as large as itself revolving round it; but the explanation remained merely a surmise until K.
The occurrence of change, either periodic or irregular, in the colour of individual stars, has been suspected by many observers; but such a colour-variability is necessarily very difficult to establish.
The extreme variability in the amount of rainfall is remarkable.'
The greatest variability in temperature conditions in the state occurs in the Blue Ridge, Newer Appalachian Provinces, where the most rugged and variable topography is likewise found.
Owing to its variability in this respect, and to its insolubility, certain other salts have largely replaced the sulphate in modern medicine.
These illustrations of the enormous variability of discharge serve to explain what is popularly so little understood, namely, the advantage which riparian owners, or other persons Comperei nterested in a given stream, may derive from works cation water.
The most plausible explanation is that, like the discrepancy in the secular acceleration, the observed deviation is only apparent, and arises from slow fluctuations in the earth's rotation, and therefore in our measure of time produced by the motion of great masses of polar ice and the variability of the amount of snowfall on the great continents.
The result is a variability of terrestrial latitudes generally.
Natural clays, even when most pure, show a considerable range of composition, and hence cannot be regarded as consisting of a single mineral; clay is a rock, and has that variability which characterizes all rocks.
Is a large tree remarkable for the variability in the shape of its leaves, which are linear in young trees and vigorous shoots, and broad and ovate on older branches.
The variability in form and function of the second maxillae is sufficiently shown by the fact that G.