Temperature Sentence Examples
They can't keep her temperature down.
The nights were still cold into April, but the temperature climbed into the 60's during the day.
The temperature of his tent seemed to drop by ten degrees.
May was less than a week old and the temperature was still volatile.
The temperature was in the high teens but as the sun began its ascent it felt far warmer.Advertisement
The temperature hovered around twenty-five and the sun was brilliant.
Yes, my metabolism is a lot faster than a human, so my temperature runs about a hundred and two degrees.
What was supposed to be sunshine, mild temperature and puffy white clouds turned out to be intermittent showers and a sky as gray as Dean's sweat socks.
Robots can work without ceasing in environments where the temperature is a thousand degrees.
Dean felt the temperature climbing in his face.Advertisement
These natural philosophers suggested that equal volumes of all gaseous substances must contain, at the same temperature and pressure, the same number of molecules.
Specimens of curves showing the relation of induction to magnetic field at various temperatures, and of permeability to temperature with fields of different intensities, are given in figs.
There was no humidity, an ideal temperature and enough of a breeze to perfume the air with the zillion flowers recently wakened after a tough winter or perhaps just planted to welcome the approaching summer season.
A closed stove acts mainly by convection; though when heated to a high temperature it gives out radiant heat.
Hydriodic acid and phosphorus at high temperature give a dihydro-compound, whilst sodium and alcohol give hexaand octo-hydro derivatives.Advertisement
The spleen continues to enlarge; the urine is now scanty and high-coloured; the body temperature is high, but the highest temperatures occur during the chill; there is considerable thirst; and there is the usual intellectual unfitness, and it may be confusion, of the feverish state.
Sleep may overtake the patient in the midst of the sweating stage, and he awakes, not without some feeling of what he has passed through, but on the whole well, with the temperature fallen almost or altogether to the normal, or it may be even below the normal; the pulse moderate and full; the spleen again of its ordinary size; the urine that is passed after the paroxysm deposits a thick brick-red sediment of urates.
Known quantities of the solutions are taken, and the temperature of each is accurately measured before mixing, the solutions having been allowed as far as possible to adjust themselves to the same temperature.
The change of temperature of the solutions after the mixing has taken place is then observed with the usual precautions.
In the above instance the sulphur is supposed to be in the solid rhombic modification, the oxygen and sulphur dioxide being in the gaseous state, and the initial and final systems being at the ordinary temperature.Advertisement
There is much malaria in the wooded districts of the east and on the higher campos, where the daily extremes of temperature are great, lung and bronchial diseases are common.
The rainfall, though not heavy, is sufficient to maintain such vegetation as is compatible with the conditions of temperature, and the surface is often swampy or peaty.
The south-westerly winds which prevail north of the equator during the hot half of the year, to which navigators have given the name of the south-west monsoon (the latter word being a corruption of the Indian name for season), arise from the great diminution of atmospheric pressure over Asia, which begins to be strongly marked with the great rise of temperature in April and May, and the simultaneous relatively higher pressure over the equator and the regions south of it.
This diminution of pressure, which continues as the heat increases till it reaches its maximum in July soon after the solstice, is followed by the corresponding development of the south-west monsoon; and as the barometric pressure is gradually restored, and becomes equalized within the tropics soon after the equinox in October, with the general fall of temperature north of the equator, the south-west winds fall off, and are succeeded by a north-east monsoon, which is developed during the winter months by the relatively greater atmospheric pressure which then occurs over Asia, as compared with the equatorial region.
The heated body of air carried from the Indian Ocean over southern Asia by the south-west monsoon comes up highly charged with watery vapour, and hence in a condition to release a large body of water as rain upon the land, whenever it is brought into circumstances which reduce its temperature in a notable degree.Advertisement
Such a reduction of temperature is brought about along the greater part of the coasts of India and of the BurmoSiamese peninsula by the interruption of the wind current by continuous ranges of mountains, which force the mass of air to rise over them, whereby the air being rarefied, its specific capacity for heat is increased and its temperature falls, with a corresponding condensation of the vapour originally held in suspension.
The prevailing winds in most parts are westerly, but sudden changes, as well as the extremes of temperature, are caused mainly by the frequent shifting of the wind from N.W.
Therefore the flesh, especially of the larger kinds, is of a red colour; and the energy of their muscular action causes the temperature of their blood to be several degrees higher than in other fishes.
A higher temperature decomposes this body into carbon dioxide and itaconic acid, C 5 H 6 0 4, which, again, by the expulsion of a molecule of water, yields citraconic anhydride, C 5 H 4 0 3.
Others are deprived of a part of their more volatile constituents by spontaneous evaporation, or by distillation, in vacuo or otherwise, at the lowest possible temperature.
The cracking process practically consists in distilling the oils at a temperature higher than the normal boiling point of the constituents which it is desired to decompose.
The steam is superheated and may thus be heated to any desired temperature without increase of pressure, which would be liable to damage the still.
This instrument is so constructed that the higher temperature needed can be readily applied, and it is fitted with a stirrer to equalize the heating of the contents of the oil-cup.
By means of this instrument the time occupied in the flow of a measured quantity of the oil through a small orifice at a given temperature is measured.
Even the steppe exhibits great contrasts of temperature; there the rainfall is slight and the air exceedingly exhilarating and healthy.
It is, however, requisite to make provision for the effect of changes in atmospheric temperature.
Then no changes of external temperature can affect the sag of the wire, and the only thing which can alter its length relatively to the supporting bar is the passage of a current through it.
The reason is that the heat produced in a given time in a wire is proportional to the square of the strength of the current passing through it, and hence the rate at which the heat is produced in the wire, and therefore its temperature, increases much faster than the current itself increases.
Changes of atmospheric temperature affect both wires equally and do not tilt the mirror.
By blending the coco-nut oil with other less saponifiable substances such as tallow, lard, cotton-seed oil, &c., and effecting the mixing and saponification at a slightly higher temperature, soaps are obtained which resemble milled toilet soaps.
The crude product is very impure and possesses an offensive smell; it may be purified by forcing a fine spray of lime water through the liquid until the escaping water is quite clear, the washed bisulphide being then mixed with a little colourless oil and distilled at a low temperature.
The sound, which has been heard by modern travellers, is generally attributed to the passage of the air through the pores of the stone, chiefly due to the change of temperature at sunrise.
It is insoluble in acids and decomposes when heated to a sufficiently high temperature.
The temperature is moderated by the north-east trade winds, which, somewhat modified by local conditions, blow throughout the year, briskly during the day and more mildly during the night.
With Sydney Young and others he investigated the critical state and properties of liquids and the relationship between their vapour pressures and temperature, and with John Shields he applied measurements of the surface tension of liquids to the determination of their molecular complexity.
The meal can be baked into "cake" or biscuit, as the Passover cake of the Jews; but it cannot be made into loaves in consequence of the great difficulty in rupturing the starch grains, unless the temperature be raised to a considerable height.
In the latter division are comprised the two Vindhyan districts of Saugor and Damoh, Jubbulpore at the head of the Nerbudda valley, and the four Satpura districts of Mandla, Seoni, Betul and Chhindwara, which enjoy, owing to their greater elevation, a distinctly lower average temperature than the rest of the province.
In the cold weather the temperature in Nagpur and the other hot districts is about the same as in Calcutta and substantially higher than that of northern India.
In the autumn months malarial fever is prevalent in all thickly forested tracts and also in the rice country; but on the whole the province is considered to be healthy, and as the rains break fairly regularly in June and produce an immediate fall in the temperature, severe heat is only experienced for a period of from two to three months.
From a study of the free elements Cannizzaro showed that an element may have more than one molecular weight; for example, the molecular weight of sulphur varied with the temperature.
Thus, the equation 2112+02 =2H20 not only represents that certain definite weights of hydrogen and oxygen furnish a certain definite weight of the compound which we term water, but that if the water in the state of gas, the hydrogen and the oxygen are all measured at the same temperature and pressure, the volume occupied by the oxygen is only half that occupied by the hydrogen, whilst the resulting water-gas will only occupy the same volume as the hydrogen.
Having replaced the oxygen in the absorption vessels by air, they are disconnected and weighed, after having cooled down to the temperature of the room.
The limiting law expressing the behaviour of gases under varying temperature and pressure assumes the form pv= RT; so stated, this law is independent of chemical composition and may be regarded as a true physical law, just as much as the law of universal gravitation is a true law of physics.
According to the law of Avogadro, equal volumes of different gases under the same conditions of temperature and pressure contain equal numbers of molecules; therefore, since the density depends upon the number of molecules present in unit volume, it follows that for a comparison of the densities of gases, the determinations must be made under coincident conditions, or the observations reduced or re-computed for coincident conditions.
If we denote the critical volume, pressure and temperature by Vk, Pk and Tk, then it may be shown, either by considering the characteristic equation as a perfect cube in v or by using the relations that dp/dv=o, d 2 p/dv 2 =o at the critical point, that Vk = 3b, Pk= a/27b2, T ic = 8a/27b.
If we express the pressure, volume and temperature as fractions of the critical constants, then, calling these fractions the " reduced " pressure, volume and temperature, and denoting them by 7r, 0 and 0 respectively, the characteristic equation becomes (7+3/0 2)(30-i) =80; which has the same form for all substances.
Guldberg pointed out that for the most diverse substances the absolute boiling-point is about two-thirds of the critical temperature.
In the article Thermodynamics it is shown that the amount of heat required to raise a given weight of a gas through a certain range of temperature is different according as the gas is maintained at constant pressure, the volume in creasing, or at constant volume, the pressure increasing.
He regarded these anomalies as solely due to the chemical nature of the elements, and ignored or regarded as insignificant such factors as the state of aggregation and change of specific heat with temperature.
Nilson and Pettersson's observations on beryllium and germanium have shown that the atomic heats of these metals increase with rise of temperature, finally becoming constant with a value 5.6.
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.
An ethylenic or double carbon union in the aliphatic hydrocarbons has, apparently, the same effect on the boiling-point as two hydrogen atoms, since the compounds C 0 H 2 „ +2 and CoH2n boil at about the same temperature.
Laplace is due the theoretical proof that this function is independent of temperature and pressure, and apparent experimental confirmation was provided by Biot and Arago's, and by Dulong's observations on gases and vapours.
P. Dale; the more simple formula (n - i)/d, which remained constant for gases and vapours, but exhibited slight discrepancies when liquids were examined over a wide range of temperature, being adopted.
Since a/d is the real specific volume of the molecule, it is therefore a constant; hence (N2-I)/(N2+2)d is also a constant and is independent of all changes of temperature, pressure, and of the state of aggregation.
Since molecular refractions are independent of temperature and of the state of aggregation, it follows that molecular dispersions must be also independent of these conditions; and hence quantitative measurements should give an indication as to the chemical composition of substances.
At the critical point liquid and vapour become identical, and, consequently, as was pointed out by Frankenheim in 1841, the surface tension is zero at the critical temperature.
The relation they suspected to be of the form -yS = KT, where K is a constant analogous to R, and S the surface containing one gramme-molecule, y and T being the surface tension and temperature respectively.
The whole is enclosed in a jacket connected with a boiler containing a liquid, the vapour of which serves to keep the inner tube at any desired temperature.
In general, polysymmetric and polymorphous modifications suffer transformation when submitted to variations in either temperature or pressure, or both.
At the same time there may be conditions of temperature and pressure at which polymorphs may exist side by side.
We have already seen that temperature and pressure exercise considerable influence in this direction.
From supersaturated solutions the form unstable at the temperature of the experiment is, as a rule, separated, especially on the introduction of a crystal of the unstable form; and, in some cases, similar inoculation of the fused substance is attended by the same result.
The days are usually hot and the nights cold, the variations in temperature being a fruitful cause of bronchial and pulmonary diseases.
The drug is not a true specific, as quinine is for malaria, since it rarely, if ever, prevents the cardiac damage usually done by rheumatic fever; but it entirely removes the agonizing pain, shortly after its administration, and, an hour or two later, brings down the temperature to normal.
The temperature is rather remarkable, there being an intermediate cold layer between 25 and 50 fathoms. This is due to the sinking of the cold surface water (which in winter reaches freezing-point) on to the top of the denser more saline water of the greater depths.
So also any exhaustive survey of the temperature and salinity of the sea at a great number of points on and below the surface reveals a complexity of conditions that may defy mathematical analysis and could not easily be predicted.
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.
The regional differences, as we have seen, can De explained by the regional difference of temperature.
Corals would now grow luxuriantly in these shallow coastal waters of increasing temperature, forming reefs and extensive coral flats.
In the same way artificial glass can be devitrified if it be kept at a temperature slightly below the fusing point for some days.
The temperature coefficient of conductivity has approximately the same value for most aqueous salt solutions.
The influence of temperature on the conductivity of solutions depends on (I) the ionization, and (2) the frictional resistance of the liquid to the passage of the ions, the reciprocal of which is called the ionic fluidity.
At extreme dilution, when the ionization is complete, a variation in temperature cannot change its amount.
The rise of conductivity with temperature, therefore, shows that the fluidity becomes greater when the solution is heated.
As the concentration is increased and un-ionized molecules are formed, a change in temperature begins to affect the ionization as well as the fluidity.
But the temperature coefficient of conductivity is now generally less than before; thus the effect of temperature on ionization must be of opposite sign to its effect on fluidity.
The ionization of a solution, then, is usually diminished by raising the temperature, the rise in conductivity being due to the greater increase in fluidity.
We can calculate the heat of formation from its ions for any substance dissolved in a given liquid, from a knowledge of the temperature coefficient of ionization, by means of an application of the well-known thermodynamical process, which also gives the latent heat of evaporation of a liquid when the temperature coefficient of its vapour pressure is known.
It will be noticed that when dE/dT is zero, that is, when the electromotive force of the cell does not change with temperature.
The earliest formulation of the subject, due to Lord Kelvin, assumed that this relation was true in all cases, and, calculated in this way, the electromotive force of Daniell's cell, which happens to possess a very small temperature coefficient, was found to agree with observation.
For cells in which the electromotive force varies with temperature, the full equation given by Gibbs and Helmholtz has also been confirmed experimentally.
Again, we may calculate the osmotic work done, and, if the whole cycle of operations be supposed to occur at the same temperature, the osmotic work must be equal and opposite to the electrical work of the first operation.
When the solutions may be taken as effectively dilute, so that the gas laws apply to the osmotic pressure, this relation reduces to E _ nrRT to c1 ey gE c2 where n is the number of ions given by one molecule of the salt, r the transport ratio of the anion, R the gas constant, T the absolute temperature, y the total valency of the anions obtained from one molecule, and c i and c 2 the concentrations of the two solutions.
Hence, if we assume that, in the Daniell's cell, the temperature coefficients are negligible at the individual contacts as well as in the cell as a whole, the sign of the potential-difference ought to be the same at the surface of the zinc as it is at the surface of the copper.
The temperature varies almost as much as the rainfall.
Saturated steam is steam in contact with liquid water at a temperature which is the boiling point of the water and condensing point of the steam; superheated steam is steam out of contact with water heated above this temperature.
While elevating the temperature they bring more moisture into the air and produce a change not entirely desirable.
This while averaging a lower temperature than (A) is not so subject to change; it retains the snow for sleighing, which is a boon to the farmer.
Climate (C), that of Fort Chipewyan, having a mean winter temperature of.
Observations in temperature and salinity have only been taken during summer.
There is thus a minimum circulation in the greater depths causing there uniformity of temperature, an absence of the circulation of oxygen by other means than diffusion, and a protection of the sulphuretted hydrogen from the oxidation which takes place in homologous situations in the open ocean.
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.
Heavy rainfall, high temperature and fertile soil combine to cover the greater part of the state, and particularly the alluvial regions and the coast swamps, with a most luxuriant subtropical vegetation, both arborescent and herbaceous.
The range of temperature is not sufficient to give the variety of annual wild flowers of more northern climates; nevertheless flowers cover the bottom lands and uplands in great profusion.
The climate of Cuba is tropical and distinctively insular in characteristics of humidity, equability and high mean temperature.
It behaves as a powerful reducing agent, and on hydrolysis with dilute mineral acids is decomposed into formaldehyde and hydroxylamine, together with some formic acid and ammonia, the amount of each product formed varying with temperature, time of reaction, amount of water present, &c. This latter reaction is probably due to some of the oxime existing in the form of the isomeric formamide HCO NH 2.
Howles, who, employing a high tension alternating arc, showed that the effectiveness depended upon the temperature.
The conversion of nitrogen into ammonia by electricity has received much attention, but the commercial aspect appears to have been first worked out by de Hemptinne in 1900, who used both the spark and silent discharge on mixtures of hydrogen and nitrogen, and found that the pressure and temperature must be kept low and the spark gap narrow.
It forms a mass of deep blue crystals at the temperature of liquid air.
It is somewhat volatile at ordinary temperature, and its aqueous solution possesses a strongly acid reaction.
Owing to the extreme dryness of the atmosphere and the fact that there is always a breeze, usually from the N.W., this heat is felt much less than a greatly lower temperature in a more humid atmosphere.
These icebergs float away, and are gradually melted in the sea, the temperature of which is thus lowered by cold stored up in the interior of Greenland.
At Julianehaab in the extreme south-west the winter is not much colder than that of Norway and Sweden in the same locality; but its mean temperature for the whole year probably approximates to that on the Norwegian coast 600 m.
The climate of the interior has been found to be of a continental character, with large ranges of temperature, and with an almost permanent anti-cyclonic region over the interior of the inland ice, from which the prevailing winds radiate towards the coasts.
On the 64th parallel the mean annual temperature at an elevation of 6560 ft.
Minnesota has the characteristic climate of the North Central group of states, with a low mean annual temperature, a notably rarefied atmosphere that results in an almost complete absence of damp foggy weather, and an unusual dryness which during the rather long winters considerably neutralizes the excessive cold.
At the same time temperature observations are made.
These show the magnitudes of the layers of different salinity and temperature beneath the surface, and when a number of sections are compared the differences from season to season and from year to year can be seen.
The proportion varies with the temperature.
The spring outburst of plant life in the sea culminates about April, just about the time when the temperature of the water begins to rise rapidly.
The increasing temperature raises the rate of animal metabolism, while the higher alkalinity is a stimulus to cell-division.
Following that again is a less well-marked maximum of phyto-plankton in the autumn, occurring just after the period of highest sea temperature.
If this is admitted the poverty of tropical sea-water in mineral nitrogen compounds is explained by the higher temperature, which accelerates the activity of denitrifying bacteria.
Differences of temperature and atmospheric pressure must disturb this equilibrium, but the movements of both ocean and atmosphere lead to a high degree of uniformity in both envelopes as regards their gaseous constitutions.
Therefore a reduction in the partial pressure of the gas in the atmosphere, or a rise in the temperature of the water, or a violent agitation of the sea itself, will lead to precipitation of calcium carbonate.
In Pleistocene times, then, when there were prolonged glacial ages, the sea-level was lowered and at the same time there was a reduction in sea temperature, so that the rate of reproduction of the coral polypes, and so the growth of reefs, was diminished.
The nature of the soil appears, however, to be of secondary importance, provided that it is able to hold moisture and that climatic conditions of high and even temperature with considerable rainfall and absence of wind are satisfied.
The coagulated rubber separated from the watery fluid is cut up into small pieces and passed through the grooved rollers of the washing machine, from which it issues in sheets, long crinkled ribbons or " crepe," which are then dried in hot air chambers or in a vacuum dryer, by which means the water is dissipated at a lower temperature.
When caoutchouc is heated slightly above the temperature of boiling water it becomes softer and loses much of its elasticity, which, however, it recoveres on cooling.
If an article made of cut sheet be immersed for a few minutes in a bath of melted sulphur, maintained at a temperature of 120 0 C., the rubber absorbs about one-tenth of its weight of that element, and, although somewhat yellowish in colour from the presence of free sulphur, it is still unvulcanized, and unaltered as regards general properties.
In order to make spongy or porous rubber, some material is incorporated which will give off gas or vapour at the vulcanizing temperature, - such as carbonate of ammonia, crystallized alum, and finely ground damp sawdust.
For example, a rise in temperature of the bath causes an increase in its conductivity, so that a lower E.M.F.
On account of its transparency and its resistance to fire and sudden changes of temperature, mica has been much used for the windows of stoves and lanterns, for the peep-holes of furnaces, and the chimneys of lamps and gas-burners.
The temperature in the hot season is very oppressive and relaxing.
In general the climate, which varies with the configuration of the surface, is moderate and healthy, although subject to rapid changes of temperature.
While by the English and Carinthian processes as much lead as possible is extracted in the furnace, with the Silesian method a very low temperature is used, thus taking out about one-half of the lead and leaving very rich slags (50% lead) to be smelted in the blast-furnace, the ultimate result being a very much higher yield than by either of the other processes.
A stick of green wood is forced into it, and the vapours and gases set free expose new surfaces to the air, which at this temperature has only a mildly oxidizing effect.
The lead is melted down at a low temperature and drossed.
The temperature is then raised, and the scum which forms on the surface is withdrawn until pure litharge forms, which only takes place after all the tin, arsenic and antimony have been eliminated.
When kept fused in the presence of air lead readily takes up oxygen, with the formation at first of a dark-coloured scum, and then of monoxide PbO, the rate of oxidation increasing with the temperature.
Strong acid does act, the more so the greater its concentration and the higher its temperature.
Tin unites with lead in any proportion with slight expansion, the alloy fusing at a lower temperature than either component.
The Kassner process for the manufacture of oxygen depends upon the formation of calcium plumbate, Ca2Pb04, by heating a mixture of lime and litharge in a current of air, decomposing this substance into calcium carbonate and lead dioxide by heating in a current of carbon dioxide, and then decomposing these compounds with the evolution of carbon dioxide and oxygen by raising the temperature.
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.
On the other hand, the magnetic properties of a substance are affected by such causes as mechanical stress and changes of temperature.
Shimizu 3 indicate that Steinmetz's formula holds for nickel and annealed cobalt up to B =3000, for cast cobalt and tungsten steel up to B =8000, and for Swedish iron up to B =18,000, the range being in all cases extended at the temperature of liquid air.
Unfortunately the effects of magnetization upon the specific resistance of bismuth vary enormously with changes of temperature; it is therefore necessary to take two readings of the resistance, one when the spiral is in the magnetic field, the other when it is outside.
Recent researches have shown that other imporant changes in its properties occur at the same critical temperature.
Ordinary magnetizable iron is in many respects an essentially different substance from the non-magnetizable metal into which it is transformed when its temperature is raised above a certain point.
The primary coil carried the magnetizing current; the secondary, which was wound inside the other, could be connected either with a ballistic galvanometer for determining the induction, or with a Wheatstone's bridge for measuring the resistance, whence the temperature was calculated.
For strong magnetizing forces (which in these experiments did not exceed II= 48.9) the permeability remains almost constant at its initial value (about 400), until the temperature is within nearly i oo of the critical point; then the permeability diminishes more and more rapidly until the critical point is reached and the magnetization vanishes.
The results of a typical experiment are given in the annexed table, which shows how greatly the hysteresis loss is diminished as the critical temperature is approached.
The temperature was determined by a platinum-rhodium and platinum thermo-j unction in contact with the metal.
When the curve after its steep descent has almost reached the axis, it bends aside sharply and becomes a nearly horizontal straight line; the authors suggest that the critical temperature should be defined as that corresponding to the point of maximum curvature.
They showed that the permeability of this sample of iron was considerably diminished at the lower temperature.
Most of the permeability-temperature curves were more or less convex towards the axis of temperature, and in all the experiments except those with annealed iron and steel wire, the permeability was greatest at the lowest temperature.
Honda and Shimizu have made similar experiments at the temperature of liquid air, employing a much wider range of magnetizing forces (up to about 700 C.G.S.) and testing a greater variety of metals.
The permeability of cobalt, both annealed and unannealed, was always diminished at the low temperature.
The range of + B within which Steinmetz's formula is applicable becomes notably increased at low temperature.
The first immersion into liquid air generally produced a permanent decrease of magnetic moment, and there was sometimes a further decrease when the metal was warmed up again; but after a few alternations of temperature the changes of moment.
If, however, this non-magnetic substance is cooled to a temperature a few degrees below freezing-point, it becomes as strongly magnetic as average cast-iron (µ = 62 for H = 40), and retains its magnetic properties indefinitely at ordinary temperatures.
Steinmetz's formula applies only for very weak inductions when the alloys are at the ordinary temperature, but at the temperature of liquid air it becomes applicable through a wide range of inductions.
Guillaume' the temperature at which the magnetic susceptibility of nickel-steel is recovered is lowered by the presence of chromium; a certain alloy containing chromium was not rendered magnetic even by immersion in liquid air.
He invented magnets that could withstand the effects of percussion and ordinary temperature variations.
Now iron, nickel and cobalt all lose their magnetic quality when heated above certain critical temperatures which vary greatly for the three metals, and it was suspected by Faraday 3 as early as 1845 that manganese might really be a ferromagnetic metal having a critical temperature much below the ordinary temperature of the air.
The critical temperature (if there is one) was not reached in Faraday's experiment; possibly even the temperature of -250 C., which by the use of liquid hydrogen has now become accessible, might still be too high.
Guillaume 6 explains the ferromagnetism of Heusler's alloy by supposing that the naturally low critical temperature of the manganese contained in it is greatly raised by the admixture of another appropriate metal, such as aluminium or tin; thus the alloy as a whole becomes magnetizable at the ordinary temperature.
He found that the susceptibility for unit of mass,.K, was independent of both pressure and magnetizing force, but varied inversely as the absolute temperature,.
It is pointed out that this formula may be used as a temperature correction in magnetic determinations carried out in air.
For all diamagnetic substances, except antimony and the value of K was found to be independent of the temperature.
Curie has shown, for many paramagnetic bodies, that the specific susceptibility K is inversely proportional to the absolute temperature 0.
Hence may be deduced an explanation of the fact that, while the susceptibility of all known diamagnetics (except bismuth and antimony) is independent of the temperature, that of paramagnetics varies inversely as the absolute temperature, in accordance with the law of Curie.
It is found (Bourne, 24) that some species of scorpion faint at a temperature of 4 0 0 Cent.
He investigated also the variations of temperature in the atmosphere and ocean.
There is less uniformity in temperature, and the elevated chapadas are generally hotter during the day and cooler at night than are localities of the same latitude on the coast.
The sun temperature is high on these barren tablelands, but the nights are cool and refreshing.
Minas Geraes is forested along its water courses and along its southern border only; its sun temperature, therefore, is high and the rainfall in its northern districts is comparatively light.
Sao Paulo is partly covered by open cameos, and these also serve to augment the maximum temperature.
In the Parahyba valley, which extends across the state of Rio de Janeiro, the mean temperature is somewhat higher than it is in Sao Paulo and Minas Geraes, and the nights are warmer, but the higher valleys of the Serra do Mar enjoy a delightfully temperate climate.
The mean temperature at Durban, records taken at 260 ft.
Both the humidity and the temperature are increased by the great mass of water, the Mozambique current, flowing south from the equatorial regions.
The acid salts are obtained by the addition of one molecule of alkali to two molecules of the acid in concentrated alcoholic solution at a low temperature.
The minimum of the temperature is attained in January and the maximum in July.
St Winifred's holy well, one of the wonders of Wales, sends up water at the rate of 21 tons a minute, of an almost unvarying temperature, higher than that of ordinary spring water.
Thus he carried on the narrative of orderly development from the point at which it was left by Kant and Laplace - explaining by reference to the ascertained laws of physics and chemistry the configuration of the earth, its mountains and seas, its igneous and its stratified rocks, just as the astronomers had explained by those same laws the evolution of the sun and planets from diffused gaseous matter of high temperature.
As an application of this result, let us investigate what amount of temperature disturbance in the tube of a telescope may be expected to impair definition.
If the change of temperature progressed uniformly from one side to the other, the result would be a lateral displacement of the image without loss of definition; but in general both effects would be observable.
In longer tubes a similar disturbance would be caused by a proportionally less difference of temperature.
There is also some uncertainty as to the actual temperature of the grating when in use.
By reducing the oxide with charcoal at a high temperature, he obtained a product which he took to be metallic uranium.
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.
But in addition to these distinctive characters, living matter has some other peculiarities, the chief of which are the dependence of all its activities upon moisture and upon heat, within a limited range of temperature, and the fact that it usually possesses a certain structure or organization.
As has been said, a large proportion of water enters into the composition of all living matter; a certain amount of drying arrests vital activity, and the complete abstraction The properties of living matter are intimately related to temperature.
In warm-blooded animals, such as birds and mammals, protective mechanisms for the regulation of temperature enable them to endure exposure to extreme heat or cold, but in such cases the actually living cells do not appreciably rise or fall in temperature.
And it remains to be seen, how far the death of any form of living matter, at a given temperature, depends on the destruction of its fundamental substance at that heat, and how far death is brought about by the coagulation of merely accessory compounds.
After this the metal is allowed to rest for a time in the pot at a temperature above its freezing point and is then ladled out into ingot forms, care being taken at each stage to ladle off the top stratum.
To test the purity of the metal the tin-smelter heats the bars to a certain temperature just below the fusing point, and then strikes them with a hammer or lets them fall on a stone floor from a given height.
An ingot of tin is pure white (except for a slight tinge of blue); the colour depends, however, upon the temperature at which it is poured - if too low, the surface is dull, if too high, iridescent.
The solubility in ether-alcohol may be owing to a lower degree of nitration, or to the temperature conditions under which the process of manufacture has been carried on.
The year is divided into two seasons, the dry and wet, the latter occurring from April to October, when the temperature is also the highest.
The temperature at which the limb is kept, no doubt, favours and hastens the natural process of destruction, so that putrefaction shows itself sooner than would be the case with a dead tissue removed from the body and kept at a lower temperature.
Previously consumptive individuals were carefully excluded from contact with fresh air, and were advised to live in rooms almost hermetically sealed and kept at a high temperature.
When the solution in the strong acid is allowed to stand, some nitric acid is first evolved, and as the temperature rises this is followed by a general decomposition of the substance, though not necessarily an explosive one.
Ammonium hydroxide has no appreciable action at ordinary temperatures, but strong solutions of sodium or potassium hydroxides start a decomposition, with rise of temperature, in which some nitrate and always some nitrite is produced.
On the one hand he worked out the general theory of the magnetic circuit in the dynamo (in conjunction with his brother Edward), and the theory of alternating currents, and conducted a long series of observations on the phenomena attending magnetization in iron, nickel and the curious alloys of the two which can exist both in a magnetic and non-magnetic state at the same temperature.
The air underground remains throughout the year at nearly the same temperature, and is warmer in winter and cooler in summer than the outside air.
If the two openings to the mine are at different levels the difference in weight of the inside and outside air due to difference in temperature causes a current, and in the winter months large volumes of air will be circulated through the mine from this cause alone.
In a mine with shafts opening at the same level, natural ventilation once established will be effective during cold weather, as the downcast will have the temperature of the outside air, while the upcast will be filled with the warm air of the mine.
When the temperature of outside and inside air becomes equal or nearly so natural ventilation ceases or becomes insignificant.
In a mine with two shafts a ventilating current may result from other conditions creating a difference in the temperature of the air in either shaft - for example, the cooling effect of dropping water or the heating effect of steam pipes.
The special difficulties which attend deep mining, in addition to the problems of hoisting ore and raising water from great depths, are the increase of temperature of the rocks and the pressure of the overlying strata.
The possibility of hoisting and pumping from great depths has been discussed, and it remains now to consider the other conditions which will tend to limit mining operations in depth - namely, increase of temperature and increase of rock pressure.
Although liable to great extremes of temperature, and to a very scanty rainfall, the district is not unhealthy.
In the same way glass can be rendered more or less fusible, and its stability can be increased both in relation to extremes of temperature and to the chemical action of solvents.
The fluidity of glass at a high temperature renders possible the processes of ladelling, pouring, casting and stirring.
Oxidation may be effected by the addition to the glass mixture of a substance which gives up oxygen at a high temperature, such as manganese dioxide or arsenic trioxide.
Many forms of apparatus have been tried for ascertaining the temperature of glass furnaces.
It is usually essential that some parts of the apparatus shall be made to acquire a temperature identical with the temperature to be measured.
Owing to the physical changes produced in the material exposed prolonged observations of temperature are impossible.
The hotter the furnace the greater is the rise of temperature of the couple.
The electromotive force thus generated is measured by a galvanometer, the scale of which is divided and figured so that the temperature may be-directly read.
Processes of annealing, or very gradual cooling, are intended to relieve these strains, but such processes are only completely effective when the cooling, particularly through those ranges of temperature where the glass is just losing the last traces of plasticity, is extremely gradual, a rate measured in hours per degree Centigrade being required.
The empty crucible, having first been gradually dried and heated to a bright red heat in a subsidiary furnace, is taken up by means of massive iron tongs and introduced into the previously heated furnace, the temperature of which is then gradually raised.
When a suitable temperature for the fusion of the particular glass in question has been attained, the mixture of raw materials is introduced in comparatively small quantities at a time.
In the next stage of the process, the glass is raised to a high temperature in order to render it sufficiently fluid to allow of the complete elimination of these bubbles; the actual temperature required varies with the chemical composition of the glass, a bright red heat sufficing for the most fusible glasses, while with others the utmost capacity of the best furnaces is required to attain the necessary temperature.
The stirring process is begun when the glass is perfectly fluid at a temperature little short of the highest attained in its fusion, but as the stirring proceeds the glass is allowed to cool gradually and thus becomes more and more viscous until finally the stirring cylinder can scarcely be moved.
When the glass has cooled so far as to become hard and solid, the furnace is hermetically sealed up and allowed to cool very gradually to the ordinary temperature.
Lumps of glass of approximately the right weight are chosen, and are heated to a temperature just sufficient to soften the glass, when the lumps are caused to assume the shape of moulds made of iron or fireclay either by the natural flow of the softened glass under gravity, or by pressure from suitable tools or presses.
Before work begins the temperature is lowered sufficiently to render the glass viscous.
In all mercurial thermometers there is a slight depression of the ice-point after exposure to high temperatures; it is also not uncommon to find that the readings of two thermometers between the iceand boiling-points fail to agree at any intermediate temperature, although the iceand boiling-points of both have been determined together with perfect accuracy, and the intervening spaces have been equally divided.
The temperature required in the fusion of sheet-glass and of other glasses produced in tank furnaces is much lower than that attained in steel furnaces, and it is consequently pos Since the discovery of the Rntgen rays, experiments have been made to ascertain the effects of the different constituents of glass on the transparency of glass to X-rays.
Among the many developments of the Jena Works, not the least important are the glasses made in the form of a tube, from which gas-chimneys, gauge-glasses and chemical apparatus are fashioned, specially adapted to resist sudden changes of temperature.
The proportions in which these ingredients are mixed vary according to the exact quality of glass required and with the form and temperature of the melting furnace employed.
Finally, fluid steel can be run or poured off, since it is perfectly fluid, while glass cannot be thus treated, but is withdrawn from the furnace by means of either a ladle or a gatherer's pipe, and the temperature required for this purpose is much lower than.
In a sheet-glass tank there is therefore a gradient of temperature and a continuous passage of material from the hotter end of the furnace where the raw materials are introduced to the cooler end where the glass, free from bubbles and raw material, is withdrawn by the gatherers.
When flattened, the sheet is moved away from the working opening of the furnace, and pushed to a system of movable grids, by means of which it is slowly moved along a tunnel, away from a source of heat nearly equal in temperature to that of the flattening chamber.
For the commoner grades of dark-coloured bottles the glass mixture is cheapened by substituting common salt for part of the sulphate of soda, and by the addition of felspar, granite, granulite, furnace slag and other substances fusible at a high temperature.
In the walls and floor of the kiln special cooling channels or air passages are provided and by gradually opening these to atmospheric circulation the cooling is considerably accelerated while a very even distribution of temperature is obtained; by these means even the largest slabs can now be cooled in three or four days and are nevertheless sufficiently well annealed to be free from any serious internal stress.
It is attacked rapidly by fluorine at ordinary temperature, and by chlorine when heated in a current of the gas.
When pure, it is a colourless gas which is not spontaneously inflammable at ordinary temperature and pressure, but a slight increase of temperature or decrease of pressure sets up decomposition.
It decomposes water at ordinary temperature with evolution of hydrogen but without production of silicon hydride, whilst cold hydrochloric acid attacks it vigorously with evolution of hydrogen and spontaneously inflammable silicon hydride.
Sodium percarbonates of the formulae Na 2 CO 4, Na2C206, Na 2 C05, NaHCO 4 (two isomers) are obtained by the action of gaseous or solid carbon dioxide on the peroxides Na 2 0 2, Na 2 0 3, NaHO 2 (two isomers)in the presence of water at a low temperature (R.Wolffenstein and E.Peltner, Ber., 1908, 41, pp. 275, 280).
All metals, when exposed in an inert atmosphere to a sufficient temperature, assume the form of liquids, which all present the following characteristic properties.
The quality of plasticity is developed to very different degrees in different metals, and even in the same species it depends on temperature, and may be modified by mechanical or physical operations.
This varies in metals from 594 (lithium) to 22.48 (osmium), and in one and the same species is a function of temperature and of previous physical and mechanical treatment.
Of the several products, the chlorides of gold and platinum (AuC13 and PtC1 4) are the only ones which when heated beyond their temperature of formation dissociate into metal and chlorine.
By a change of temperature and pressure combined, a substance can in general be made to pass from one state into another; thus by gradually increasing the temperature a solid piece of ice can be melted into the liquid state of water, and the water again can be boiled off into the gaseous state as steam.
Again, by raising the temperature, a metal in the solid state can be melted and liquefied, and poured into a mould to assume any form desired, which is retained when the metal cools and solidifies again; the gaseous state of a metal is revealed by the spectroscope.
Conversely, a combination of increased pressure and lowering of temperature will, if carried far enough, reduce a gas to a liquid, and afterwards to the solid state; and nearly every gaseous substance has now undergone this operation.
A certain critical temperature is observed in a gas, above which the liquefaction is impossible; so that the gaseous state has two subdivisions into (i.)a true gas, which cannot be liquefied, because its temperature is above the critical temperature, (ii.) a vapour, where the temperature is below the critical, and which can ultimately be liquefied by further lowering of temperature or increase of pressure.
Ignoring temperature effect, and taking the density as a function of the pressure, surfaces of equal pressure are also of equal density, and the fluid is stratified by surfaces orthogonal to the lines of force; n ap, dy, P d z, or X, Y, Z (4) are the partial differential coefficients of some function P, =fdplp, of x, y, z; so that X, Y, Z must be the partial differential coefficients of a potential -V, such that the force in any direction is the downward gradient of V; and then dP dV (5) ax + Tr=0, or P+V =constant, in which P may be called the hydrostatic head and V the head of potential.
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.
These equations can be made to represent the state of convective equilibrium of the atmosphere, depending on the gas-equation p = pk =RA (6) where 0 denotes the absolute temperature; and then d9 d p R dz - dz (p) n+ 1' so that the temperature-gradient deldz is constant, as in convective equilibrium in (I I).
With uniform temperature, taking h constant in the gas-equation, dp / dz= =p / k, p=poet/ k, (9) so that in ascending in the atmosphere of thermal equilibrium the pressure and density diminish at compound discount, and for pressures p 1 and 1, 2 at heights z 1 and z2 (z1-z2)11?
The vine requires a high summer temperature and a prolonged period in which to ripen its fruit.
Where these are forthcoming, it can be profitably cultivated, even though the winter temperature be very low.
The temperature must, however, be regulated according to the variety, Muscats requiring a higher temperature from the time their bunches show than Hamburghs.
The boiling juice is run down into subsiding tanks, where it cools, and at the same time the albumen, which has been suddenly coagulated by momentary exposure to high temperature, falls to the bottom of the tank, carrying with it the vegetable and other matters which were in suspension in the juice.
In this it passes through four sheets of water, by which it is not only freed from any dust and dirt that may have come over with it from the kiln, but is also cooled to a temperature which permits an air-pump to withdraw the gas from the kiln, through the gas-washer, and force it into the saturators, without overheating.
These are set in a kiln or oven, and are kept at as even a temperature as possible, corresponding to a dull cherry-red.
This disintegration is brought about chiefly by changes in temperature, and by the action of the rain, the oxygen, and the carbon dioxide of the air.
Such alterations in temperature produce strains which frequently result in the chipping off of small fragments of the material composing the stone.
If the soil holds too much it becomes water-logged and its temperature falls below the point for healthy growth, at any rate of the kinds of plants.
In addition, the temperature of the soil largely controls the yield of crops which can be obtained from the land.
Soil whose temperature remains low, whether from its northerly aspect or from its high water content or other cause, is unsatisfactory, because the germination of seeds and the general life processes of plants cannot go on satisfactorily except at certain temperatures well above freezing-point.
It holds water well and is consequently cold, needing the application of much heat to raise its temperature.
In the majority of cases the good results obtained are more particularly due to the setting free of " dormant " or " latent " food constituents and to the amelioration of the texture of the soil, so that its aeration, drainage, temperature and water-holding capacity are altered for the better.
At a red heat it evolves oxygen with the formation of potassium nitrite, which, in turn, decomposes at a higher temperature.
The caliche is worked up in loco for crude nitrate by extracting the salts with hot water, allowing the suspended earth to settle, and then transferring the clarified liquor, first to a cistern where it deposits part of its sodium chloride at a high temperature, and then to another where, on cooling, it yields a crop of crystals of purified nitrate.
In general, tropical and semitropical conditions as to temperature, with a comparatively dry climate, give the best results.
Dark-coloured leaves are produced when the temperature is allowed to mount higher than when light leaves are required.
It is then kept at a moderate and fairly uniform temperature in a warehouse, when, although there is no marked outward change, the tobacco becomes more mellow.
The fermentation is very carefully controlled, and to obtain the desired light colour the temperature is kept comparatively low.
If the zinc is present as blende, this operation offers considerable difficulties, because in the roasting process the zinc sulphide passes in the first instance into sulphate, which demands a high temperature for its conversion into oxide.
For the desulphurization of zinc blende where it is not intended to collect and save the sulphur there are many mechanical kilns, generally classified as straight-line, horse-shoe, turret and shaft kilns; all of these may be made to do good work on moderately clean ores which do not melt at the temperature of desulphurization.
To start a new furnace, the front side is closed provisionally by a brick wall, a fire lighted inside, and the temperature raised very gradually to a white heat.
The charging operation being completed, the temperature is raised, and as a consequence an evolution of carbon monoxide soon begins, and becomes visible by the gas bursting out into the characteristic blue flame.
A bath, even of very impure zinc, is allowed to stand at about the temperature of the melting-point of the metal for forty-eight or more hours, whereupon the more easily oxidizable impurities can be largely removed in the dross at the top, the heavier metals such as lead and iron settling towards the bottom.
If zinc be cast into a mould at a red heat, the ingot produced is laminar and brittle; if cast at just the fusing-point, it is granular and sufficiently ductile to be rolled into sheet at the ordinary temperature.
An impure form of the salt is prepared by roasting blende at a low temperature.
North of Katif it is desert and only inhabited by nomads; at Katif, however, and throughout the district to the south bordering on the Gulf of Bahrein there are ample supplies of underground water, welling up in abundant springs often at a high temperature, and bringing fertility to an extensive district of which El Hofuf, a town of 15,000 to 20,000 inhabitants, is the most important centre.
In the northern desert the temperature is subject to extreme variations.
From observations made at Sana by Manzoni, Defiers and Glaser, the mean temperature for the year of that city at an altitude of 7300 ft.
The temperature of the electric furnace, whether of the arc or incandescence type, is practically limited to that at which the least easily vaporized material available for electrodes is converted into vapour.
Moissan showed that at this temperature the most stable of mineral combinations are dissociated, and the most refractory elements are converted into vapour, only certain borides, silicides and metallic carbides having been found to resist the action of the heat.
It is not necessary that all electric furnaces shall be run at these high temperatures; obviously, those of the incandescence or resistance type may be worked at any convenient temperature below the maximum.
The climate is rather changeable, and rapid falls of temperature are not uncommon.
The pure salt is dissolved in hot water and decomposed with ammonia to produce a slightly ammoniacal hydrated oxide; this, when ignited in platinum, leaves pure TiO 2 in the form of brownish lumps, the specific gravity of which varies from 3.9 to 4.25, according to the temperature at which it was kept in igniting.
It can be grown in parks and gardens, and thrives well; but the young plants are unable to bear great variations of temperature.
In 1846 he began experiments on the temperature of the earth at different depths and in different soils near Edinburgh, which yielded determinations of the thermal conductivity of trap-tufa, sandstone and pure loose sand.
Towards the end of his life he was occupied with experimental inquiries into the laws of the conduction of heat in bars, and his last piece of work was to show that the thermal conductivity of iron diminishes with increase of temperature.
Almost all these springs are at a very hot temperature, often at boiling point.
When the wind rises above the snow-capped Andes, the last particle of moisture is wrung from it that a very low temperature can extract.
Meeting with no evaporating surface, and with no temperature colder than that to which it is subjected on the mountain-tops, this wind reaches the ocean before it becomes charged with fresh moisture.
Generally the components of a mixture will be vaporized in the order of their boiling-points; consequently if the condensates or "fractions" corresponding to definite ranges of temperature be separately collected, it is obvious that a more or less partial separation of the components will be effected.
It generally happens that much of the mercury column is outside the flask and consequently at a lower temperature than the bulb, hence a correction of the observed temperature is necessary.
This method is adopted for substances which decompose at their boiling-points under ordinary pressure, and, generally, when it is desirable to work at a lower temperature.
Of the third type is the Warren column consisting of a spiral kept at a constant temperature by a liquid bath.
The mixture consequently distils at the temperature at which the sum of the partial pressures equals that of the atmosphere.
Both components come over in a constant proportion until one disappears; it is then necessary to raise the temperature in order to distil the residue.
The composition of the distillate is determinate (by Avogadro's law) if the molecular weights and vapour pressure of the components at the temperature of distillation be known.
This will then distil at a constant temperature.
In its simplest form the apparatus consists of a straight tube, made of glass, porcelain or iron according to the temperature required and the nature of the reacting substances, heated in an ordinary combustion furnace, the mixture entering at one end and the vapours being condensed at the other.
Above this "separator" is a reflux condenser, termed the "cooler," maintained at the correct temperature so that only the more volatile component passes to the receiver.
It dissociates when heated to a high temperature and is not affected by oxygen.
It is a colourless, amorphous solid, which is almost insoluble in water, its solubility diminishing with increasing temperature; it is appreciably soluble in concentrated sulphuric acid.
It loses carbon dioxide when heated to high temperature.
The only organs that exhibit any sign of degeneration are those of sense, but in the ectoparasitic Trematodes simple eye-like structures are present and perhaps serve as organs of temperature.
He noticed that when ice melts it takes up a quantity of heat without undergoing any change of temperature, and he argued that this heat, which as was usual in his time he looked upon as a subtle fluid, must have combined with the particles of ice and thus become latent in its substance.
In the course of his inquiries he also noticed that different bodies in equal masses require different amounts of heat to raise them to the same temperature, and so founded the doctrine of specific heats; he also showed that equal additions or abstractions of heat produced equal variations of bulk in the liquid of his thermometers.
The climate is extremely hot and dry in summer, but the winter temperature is mild and pleasant.
In KiushiO, Shikoku and the southern half of the main island, the months of July and August alone are marked by oppressive heat at the sea-level, while in elevated districts a cool and even bracing temperature may always be found, though the direct rays of the sun retain distressing power.
The intervening sea being comparatively warm, this wind arrives at Japan having its temperature increased and carrying moisture which it deposits as snow on the western faces of the Japanese mountains.
While there can be no doubt that the luxuriance of Japans flora is due to rich soil, to high temperature and to rainfall not only plentiful but well distributed over the whole year, the wealth and variety of her trees and shrubs must be largell the result of immigration.
The uguisu is a dainty bird in the matter of temperature.
The color is fixed and the glaze set by secondary firing at a lower temperature than that necessary for hardening the p4te.
Such porcelains, however, lack the velvet-like softness and depth of tone so justly prized in the genuine monochrome, where the glaze itself contains the coloring matter, pte and glaze being tired simultaneously at the same high temperature.
He also traced a connexion between alkalinity, temperature and current-density, and showed that these conditions should be mutually adjusted.
The imperfections of the thermopile, with which he began his work, led him, about 1880, to the invention of the bolometer, an instrument of extraordinary delicacy, which in its most refined form is believed to be capable of detecting a change of temperature amounting to less than one-hundred-millionth of a degree Centigrade.
When heated with glycerin to ioo C. it yields formic acid and carbon dioxide; above this temperature, allyl alcohol is formed.
The majority of snakes are active during the day, their energy increasing with the increasing temperature; whilst some delight in the moist sweltering heat of dense tropical vegetation, others expose themselves to the fiercest rays of the midday sun.
Let us suppose that a molten mixture of two substances A and B, which at a sufficiently high temperature form a uniform liquid, and which do not combine to form definite compounds, is slowly cooled until it becomes wholly solid.
If a mixture of A and B be melted and then allowed to cool, a thermometer immersed in the mixture will indicate a gradually falling temperature.
But when solidification commences, the thermometer will cease to fall, it may even rise slightly, and the temperature will remain almost constant for a short time.
In the case of a pure substance, and of a certain small class of mixtures, there is no further fall in temperature until the substance has become completely solid, but, in the case of most mixtures, after the freezing-point has been reached the temperature soon begins to fall again, and as the amount of solid increases the temperature becomes lower and lower.
These halts in temperature that occur during the cooling of a mixture should be carefully noted, as they give valuable information concerning the physical and chemical changes that are taking place.
In such a curve the percentage composition can be plotted horizontally and the temperature of the freezing-point vertically, as in fig.