477

NOTE C.

PH. 22, page 70. This phenomenon has been matter of controversy among modern philosophers. A very curious and ingenious theory was proposed by Mr. Dalton, of Manchester, who is well known as an eminent chemical philosopher. According to him, "The particles of one elastic fluid possess no repulsive nor attractive power, or are perfectly inelastic with regard to each other; and consequently the mutual actions of the fluids is subject to the laws of inelastic bodies." Thomson's Chem. vol. iii. p. 34.

This very remarkable hypothesis does not appear to have any evidence to support it, except that of conveniency; on this account, and on this alone, it is worthy of notice; but it is liable to a multitude of objections, and although it explains the particular facts which suggested it, yet it is altogether irreconcileable to many others. Philosophers of late seem very much inclined to attribute to matter attractions and repulsions of such natures, as suits their particular views, or to deprive the particles of either or both powers in respect of certain sorts of matter, as the nature of the investigation seems to demand; we may farther observe that matter of one kind has been endowed, hypothetically, with the power of placing the particles of another kind of matter at right angles to those of its own. However convenient all this may be, in some respects, it is certain, that without the greatest care it will be attended with a great many inconveniences, and conduce much to promote confusion in the study of nature. An explanation upon established and general principles is always to be preferred, even if it should not, in every point, be so lucid as one founded on a particular hypothesis invented to solve the difficulty. The explanation we have given of this phenomenon

is deemed to be quite satisfactory, and depends on the general principles; and hence it is thought that no particular hypothesis is at all necessary, or that any should be here introduced. In this Treatise, principles the most firmly established, have been applied to explain all the leading facts in the whole range of Natural Philosophy, which have not already been explained on the same principles. Hence if the explanations of the diversified phenomena, here presented to the Reader, appear to agree with the legitimate rules of philosophising, this Work is worthy of especial attention, by all the lovers of Science, and it promises to reward the toils of those who shall labour to place the subject in a still clearer light.

FINIS.