Molecules and the Molecular Theory of Matter

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Page 5 - Avogadro's principle or hypothesis, which states that equal volumes of all gases under the same conditions of temperature and pressure contain the same number of molecules, was the extension of Dalton's Atomic Theory necessary to put the theoretical interpretation of chemistry on a solid foundation.
Page 105 - The condition of this breaking up of a configuration must depend partly on the amplitude of the oscillations, and partly on the amount of strain in the original configuration ; and we may suppose that different groups of molecules, even in a homogeneous solid, are not in similar circumstances in this respect. Thus we may suppose that in a certain number of groups the ordinary agitation of the molecules is liable to accumulate so much that every now and then the configuration of one of the groups...
Page 177 - ... by Helmholtz and Thomson has no such resources. His primitive fluid has no other properties than inertia, invariable density, and perfect mobility, and the method by which the motion of this fluid is to be traced is pure mathematical analysis. The difficulties of this method are enormous, but the glory of surmounting them would be unique.
Page 139 - This is barely, if at all, admissible, according to our present knowledge, or, rather, want of knowledge, regarding the heat of combination of zinc and copper. But suppose the metal plates and intervening spaces to be made yet four times thinner, that is to say, the thickness of each to be a four hundred millionth of a centimetre.
Page 105 - We may in this case assume that in every second a certain proportion of the groups break up, and assume configurations corresponding to a strain uniform in all directions. If all the groups were of this kind, the medium would be a viscous fluid. But we may suppose that there are other groups, the configuration of which is so stable that they will not break up under the ordinary agitation of the molecules unless the average strain exceeds a certain limit, and this limit may be different for different...
Page 176 - ... save appearances," by introducing first one hypothetical force and then another. When the vortex atom is once set in motion, all its properties are absolutely fixed and determined by the laws of motion of the primitive ft uid, which are fully expressed in the fundamental equations.
Page 171 - The hypothesis of molecular vortices is defined to be that which assumes, that each atom of matter consists of a nucleus or central point, enveloped by an elastic atmosphere, which is retained in its position by attractive forces, and that the elasticity due to heat arises from ilie centrifugal force of those atmospheres, revolving or oscillating about their nuclei or central points.
Page 139 - Now let a second plate of zinc be brought by a similar process to the other side of the plate of copper ; a second plate of copper to the remote side of this second plate of zinc, and so on till a pile is formed consisting of 50,001 plates of zinc and 50,000 plates of copper, separated by 100,000 spaces, each plate and each space one hundred-thousandth of a centimetre thick. The whole work done by electric attraction in the formation of this pile is two centimetre grammes.
Page 100 - Nachwirkung," which might be translated "elastic reaction" if the word reaction were not already used in a different sense. Sir W. Thomson speaks of the viscosity of elastic bodies. The phenomena are most easily observed by twisting a fine wire suspended from a fixed support, and having a small mirror suspended from the lower end, the position of which can be observed in the usual way by means of a telescope and scale. If the lower end of the wire is turned round through an angle not too great, and...
Page 106 - But if the solid also contains groups of smaller stability and also groups of the first kind which break up of themselves, then when a strain is applied the resistance to it will gradually diminish as the groups of the first kind break up, and this will go on till the stress is reduced to tha,t due to the more permanent groups. If the body is now left to itself, it will not at once return to its original form, but will only do so when the groups of the first kind have broken up so often as to get...

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