1S13. Elements of Chemical Philosophy, 373 



of systematic arrangement. When I first published my System 

 of Chemistry there was no better arrangement than that of 

 Macquer, Gren, and Chaptal, which were by no means fitted to 

 the state of the science. My arrangement was quite different, 

 and totally new, and constituted in fact the great difficulty of 

 constructing such a system, because it obliged me to discard all 

 preceding systematic books, and to construct my system out of 

 the original materials furnished by the chemical discoverers 

 themselves. This arrangement was disapproved of in iota by 

 every person who reviewed the work, both in Britain and 

 France ; yet it has been adopted (with a few modifications) by 

 every subsequent writer on the subject, and even at this moment 

 continues better adapted to the present state of the science than 

 any other which I have yet seen. 



This Part I. which constitutes the volume, is split into seven 

 subordinate heads, called by the author divisions. Let us take a 

 view of each of these in order. 



Division I. On the powers and foims of matter, and the 

 general laws of chemical changes. In this division he gives an 

 account of the three different forms of matter, namely, solidity, 

 liquidity, and elastic fluidity ; of gravitation ; of cohesion ; and 

 of heat. Of the phenomena of heat he gives a pretty clear, 

 though concise account, and concludes with giving it as his 

 opinion that heat is nothing else than motion, and that the laws 

 of heat are the same as the laws of motion. There have been 

 always two opinions respecting heat, which have divided philoso- 

 phers. According to one party, heat, like gravitation, is merely 

 a property of matter; according to the other, it is a peculiar 

 substance. Both of these opinions may be supported with 

 considerable plausibility. Some of the advocates for the first 

 opinion have endeavoured, like Sir Humphry Davy, to go a step 

 farther, and to show how the phenomena of heat are produced 

 by motion ; but in my opinion their conduct has been injudi- 

 cious. It is easy to defend the opinion that heat is a mere pro- 

 perty of matter; and in the present state of our knowledge, 

 impossible to refute it : but when a philosopher proceeds to 

 explain by what kind of motion heat is produced, he loses all the 

 advantages that attended the general opinion ; as nothing is easier 

 than to demonstrate the insufficiency of any kind of motion 

 hitherto devised, from that of Boyle and Mayow down to that of 

 Davy, to produce the phenomena. When it is said that the laws 

 of the communication of heat are the same as the laws of the 

 communication of motion, I confess that for my part I am at a 

 loss to comprehend the meaning of the assertion. So far from 

 conceiving them to be the same, I can see no resemblance 

 between them, except that a body, by communicating tempera- 

 ture to another, loses temperature itself, just as a body by com- 

 municating motion to another loses some of its own velocity. 



