108 Mr. A. S. Couper on a New Chemical Theory. 



direct consequence of the properties of the individual elements 

 of which they are made up. 



Nor is the doctrine of bodies being "conjugated by addition" 

 a whit in advance of that which I have just been considering. 

 This docti'ine adopts the simple expedient of dividing certain 

 combinates, if possible^ into two imaginary parts, of which one 

 or both are bodies already known. Then it tells us that these 

 two parts are found united in this body. But how they are 

 united, or what force binds them together, it does not in- 

 quire. Is this explication arbitrary ? Is it instructive ? Is it 

 science ? 



I may now be permitted to submit a few considerations rela- 

 tive to a more rational theory of chemical combination. 



As everything depends upon the method of research employed, 

 it will in the first place be necessary to find one that may be 

 relied upon. If the method is good and conscientiously cai-ried 

 out, stable and satisfactory results may be expected. If, on the 

 contrary, it is vicious, we can only expect a corresponding issue. 

 A satisfactory method is, however, not difficult to find, nor is it 

 difficult in its application. 



The principle which ought to guide all research is in every 

 case the same. It is that of analysing till it is impossible to 

 reach more simple elements, and of studying these elements in 

 all their properties and powers. "When all the properties and 

 powers of the individual elements are known, then it will be 

 possible to know the constitution of the combinates which their 

 synthesis produces. It is necessary therefore in chemical research, 

 in order to ascertain tbe various qualities and functions of the 

 different elements, — 



1. To consider the whole of chemistry as one. 



3. To take into consideration every known combinate, and to 

 study the character, functions, and properties displayed by each 

 element for itself, in each of these combinates in all their diff'er- 

 ent conditions and aspects. It is by a comparison of the diffei*- 

 ent bodies among themselves that we are able to trace the part 

 that is performed by each element separately. 



3. To trace the general principles common to all the elements, 

 noting the special properties of each. 



This method is essentially diff'erent from that whei'c one class 

 of bodies is chosen as a point for the restriction of our views of 

 the properties of the others — where only the qualities found in 

 the first are to be measured out to the rest. 



I shall now proceed to inquire how its more thorough 

 application tends to the development of a rational chemical 

 theory. 



It has been found that there is one leading feature, one in- 



