One half of the earth has therefore a greater density than the other.
One of the most remarkable of Airy's researches was his determination of the mean density of the earth.
Density of population is measured by the average number of people residing on a unit of area; but in order to compare one part of the world with another the average should, strictly speaking, be taken for regions of equal size or of equal population; and the portions of the country which are permanently uninhabitable ought to be excluded from the calculation.'
The density of solid sulphur is 2 062 to 2'070, and the specific heat 0.1712; it is a bad conductor of electricity and becomes negatively electrified on friction.
Owing to difference of density the oil and water in the anticlines separate into two layers, the upper consisting of oil which fills the anticlines, while the water remains in the synclines.
The density of helium has been determined by Ramsay and Travers as 1.98.
The solution obtained may be evaporated in vacuo until it attains a density of 1.46 when, if partially saturated with potassium hydroxide and filtered, it yields crystals of potassium pentathionate, K 2 S 5 0 6.3H 2 0.
Of trespassers the number killed per mile of line is about as large in England as in America, the density of population and of traffic in Great Britain apparently counterbalancing the laxity of the laws against trespassing in America.
The stratification, which may be concentric or excentric, appears to be due to a difference in density of the various layers.
M., and the population in 1905 was 1,684,125, showing a density of 145 inhabitants to the square mile.
In cases where the density of the air is not of average value, as on a high mountain, or with an exceptionally low barometer for example, an allowance must be made.
Experiment, however, showed that while the quotient on the left hand of this equation was fairly constant for a great number of substances, yet its value was not gR but 7 R; this means that the critical density is, as a general rule, 3.7 times the theoretical density.
The cadmium molecule, as shown by determinations of the density of its vapour, is monatomic. The metal unites with the majority of the heavy metals to form alloys; some of these, the so-called fusible alloys, find a useful application from the fact that they possess a low melting-point.
Viscosity increases with density, but oils of the same density often vary greatly; the coefficient of expansion, on the other hand, varies inversely with the density, but bears no simple relation to the change of fluidity of the oil under the influence of heat, this being most marked in oils of paraffin base.
From this he was led to the final value of 6.566 for the mean density of the earth as compared with that of water (Phil.
Biltz (Ber., 1888, 21, p. 2013; 1901, 34, p. 2490) showed that the vapour density decreased with the temperature, and also depended on the pressure.
The distance between stations on intra-urban railways is governed by the density of local traffic and the speed desired to be maintained.
For example, the physicist determines the density, elasticity, hardness, electrical and thermal conductivity, thermal expansion, &c.; the chemist, on the other hand, investigates changes in composition, such as may be effected by an electric current, by heat, or when two or more substances are mixed.
The connective tissue of the integument and basement membrane imperceptibly merges into that which surrounds the muscular bundles as they are united into denser and definite layers, and this is especially marked in those forms (Akrostomum) where the density of the muscular body-wall has considerably diminished, and the connective tissue has thus become much more prominent.
There he made the acquaintance of Thomas Andrews, whom he joined in researches on the density of ozone and the action of the electric discharge on oxygen and other gases, and by whom he was introduced to Sir W.
Henry Cavendish, from which it appeared that Cavendish, already famous by many other researches (such as the mean density of the earth, the composition of water, &c.), must be looked on as, in his day, a man of Maxwell's own stamp as a theorist and an experimenter of the very first rank.
There is no doubt that under average conditions of atmospheric density, the .005 should be replaced by 003, for many independent authorities using different methods have found values very close to this last figure.
The distribution of the mass of the atmosphere over the surface of the earth is also controlled by the relief of the crust, its greater or lesser density at the surface corresponding to the lesser or greater elevation of the surface.
A solution of the free acid may be obtained by decomposing the barium salt with dilute sulphuric acid and concentrating the solution in vacuo until it attains a density of about 1.35 (approximately), further concentration leading to its decomposition into sulphur dioxide and sulphuric acid.
He burned phosphorus in air standing over mercury, and showed that (1) there was a limit to the amount of phosphorus which could be burned in the confined air, (2) that when no more phosphorus could be burned, one-fifth of the air had disappeared, (3) that the weight of the air lost was nearly equal to the difference in the weights of the white solid produced and the phosphorus burned, (4) that the density of the residual air was less than that of ordinary air.
In practice it is generally more convenient to determine the density, the molecular volume being then obtained by dividing the molecular weight of the substance by the density.
It will be observed that Belgium leads all the countries of the world in what may be called its railway density, with the United Kingdom a far-distant second in the list, and Persia last.
Again, when tungsten hexachloride is converted into vapour it is decomposed into chlorine and a pentachloride, having a normal vapour density, but as in the majority of its compounds tungsten acts as a hexad, we apparently must regard its pentachloride as a compound in which an odd number of free affinities are disengaged.
One remarkable discovery, however, of general interest, was the outcome of a long series of delicate weighings and minute experimental care in the determination of the relative density of nitrogen gas - undertaken in order to determine the atomic weight of nitrogen - namely, the discovery of argon, the first of a series of new substances, chemically inert, which occur, some only in excessively minute quantities, as constituents of the 1 The barony was created at George IV.'s coronation in 1821 for the wife of Joseph Holden Strutt, M.P. for Maldon (1790-1826) and Okehampton (1826-1830), who had done great service during the French War as colonel of the Essex militia.
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.