General Principhs. 35 



are not less' striking. Can it fail to surprise any 

 person capable of reflection, when he is told that 

 the endless variety of created beings which na- 

 ture presents to his view are composed from not 

 more than forty- two simple substances; and that 

 into the composition of the greater number not 

 more most frequently than six or seven of these 

 elementary substances are known to enter ; for 

 the metals and most of the earths are peculiar 

 substances, and have little share in the formation 

 of animals and vegetables. 



Let it be observed, again, that chemical ana- 

 lysis has not yet probably proceeded all the 

 lengths at which it may hereafter arrive ; that 

 many substances which at present we regard as 

 simple, may hereafter be proved to be compound, 

 and that possibly the ingenuity of man may 

 never be able to reach the ultimate and elemen- 

 tary particles of bodies. 



Those matters, however, which chemists have 

 not as yet been able to decompose, they have a 

 right to treat as simple substances. They are 

 as follows: 



1 Caloric, or the matter of heat and fire *. 



* I am aware of chemists of high character accounting 

 caloric and light as distinct substances, and of the cu- 

 rious experiment of Dr. Herschell on which this opinion is 

 founded. But I have some objections to that experiment 

 not proper to be stated here ; and we know so little of the 

 chemical properties of light, considering it even as a distinct 

 substance, that its introduction at present would only con- 

 fuse the student. 



