Elements of chemistry ... / [John Murray].

  • John Murray
Date:
1810
Catalogue details

Licence: Public Domain Mark

Credit: Elements of chemistry ... / [John Murray]. Source: Wellcome Collection.

    16/1076 page 2
    Actions of this kind, under different modifications, consti- tute the various branches of Mechanical Philosophy. Astronomy has for the objects of its inquiries, the move- ments of the heavenly bodies. Optics studies the phenome- na which arise from the motion of the rays of light. T. o Pneumatics belongs the consideration of the impulse, pres- sure, and resistance of elastic fluids : and under Mecha- nics, in the extensive sense of the term, is placed the deter- mination of the effects of the same forces on non-elastic fluids and solids. In all of these, the changes which are the objects of investigation are the results of sensible mo- tions arising from the operation of powers which act at perceptible distances ; they are therefore capable of being determined with precision *, and hence a leading character of these sciences, that their principles can be established on mathematical evidence. Another class of actions of a very different nature, com- prises those which are exerted between the minute parti- cles of matter. We are liable, in regarding any solid body, to consider it as a continuous mass, all the parts of which are in perfect contact. A little inquiry, however, is suf- ficient to convince us of the error of this conclusion, and to prove to us that every mass of matter, even in its dens- est state, is composed of minute particles, which are not in contact, but are only retained within certain distances by a peculiar force. We soon discover, too, that this force is liable to be variously modified, and that in conse- quence of this, these particles are capable of acting on each other, of changing their relative positions, and of entering even into intimate combinations. Hence arises an exten-
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