bufitJOft. 



J52 CHSJIICAL THEORY.; 



t^issTtation on to labour; what is the origin of the science ? It has no prc- 

 efrecteoMiehf ^^"^'^"^ ^^ antiquity ; it was not a part of the learning of the 

 heat, and com- antients ; the Grect\s did not cultivate it ; the Romans were 

 unacquainted with it; but the Egyptians! the people of that 

 country were gfeat magicians, and could perform works 

 which persons of othci countries were unable to effect ; they 

 are supposed to have had cciwcrse with devils. What Is the 

 meaning of the new art ? to what part of nature does its 

 actions Belong ? It is called chemistry, an art whicii relates 

 to the formation of medicines to prolong the life of man ; biit 

 it has improved but little in this respect : formerly it was dig- 

 nified with the name of alcliemy, * a most august and reve- 

 rend art, the votaries of which attended to the transmutation 

 of metals, and attempted to discover the art of making gold, 

 as well as of forming an universal medicine, f by which riches 

 \?ould abound, and mankind would dispense with that la^it 

 distressing rite which hitherto has been performed by all, and 

 to which all alive must bend. 



Such a description, a fev^ years since, might have beeugive>i 

 of our art ; but since that time, to what an extensive expanse 

 has it reached ! to it all nature is subject, vvhether animat-^, or 

 unorganized ; it is a science which treats of the minute + par- 

 ticles of matter, and of the changes which take place upon ap- 

 plying difi'crcnt particles to each other. 



The different substances in nature may be divided into se- 

 veral orders, solids, fluids, gases, and § unconfinable sub- 

 stances. The three first are always cognizable to two senses'; 

 the latter are apparent to one sense alone, viz. light to the 

 sense of vision, and heat to the sense of touch 



With regard to our speculation, the last set of subbtancc<; 

 are most to be attended to, though to explain their cHocts, the 

 other substances must be had resort to. One of the most won- 

 derful phenomena in nature, but at the same time the most 

 familiar, videlicet , con?. bastion, has been attempted to be ex- 

 plained at various times, by well-adapted theory. In this 

 inquiry, and as inventors of different hypothesis have appear- 

 ed at various times, Hooke, Mayow, Beccher, Stahl, Macquer, 



*Aroertius. .'.' f Paracelsus. t i'ourcroy. Heron, 



§ Thompson. ^ 



and 



