310 Royal Institution. 



compounds. In designating these by notation, foreign writers em- 

 ployed a capital initial letter to represent the base, and the respective 

 proportionals of oxygen were indicated by dots over it : thus the 

 Nitrogen was represented by N. 



Nitrous oxide, by N. 



Nitric oxide, by N. 



Hyponitrous acid, by N. 



Nitrous acid, by N. 



Nitric acid, by N. 



Mr. Brande then proceeded to point out several objections to this 

 system when carried to its full extent and applied to practical pur- 

 poses 5 and explained the suggestions of Mr. Whewell in reference 

 to an improved and less objectionable method, in conformity with 

 which he proposed to represent the above five compounds as follows : 



Nitrogen n 



Nitrous oxide n + o 



Nitric oxide n + 2 o 



Hyponitrous acid n + 3 o 



Nitrous acid ra + 4 o 



Nitric acid n-f 5o 



The small n representing an atom, or equivalent (i. e. 14 parts by 

 weight) of nitrogen, and the o an atom (or 8 parts) of oxygen ; the 

 attached number showing the number of such atoms in the com- 

 pound. 



Mr. Brande then proceeded to explain the principle upon which 

 hydrogen, in the system of equivalent numbers, was adopted as 

 unity, and represented water as a compound of an atom of hydrogen, 

 and an atom of oxygen, or h + o; more concisely indicated by the 

 letter q, as proposed by Mr. Whewell *. Thus the liquid nitric acid 

 consists of an atom of oxygen, with five atoms of nitrogen and two 



atoms of water, and would be represented thus: n -\- 5 o + 2 q. The 

 line above, or parentheses, indicating that the elements are in che- 

 mical combination. 



The compounds of carbon with oxygen were then adverted to (the 

 equivalent of carbon being 6), and were as follows : — 



Carbonic oxide c + o 



Carbonic acid . . , c+2o 



Oxalic acid 2c-f 3o 



Ammonia was stated to be a compound of n + 3 h (one atom of 

 nitrogen and three of hydrogen), and cyanogen of n + 2 c (or one 

 atom of nitrogen and two of carbon). 



With this preliminary information, Mr. Brande proceeded to show 

 some applications of the system of notation to the explanation of che- 

 mical decompositions, such as that of oxalate of ammonia into cyano- 

 gen and water: (2c + 3o+n + 3h) = n + 2 c + 3 q: that of ni- 

 * See Phil. Mag. & Annals, N. S. vol. x. pp. 104, 405.-.Edtt. 



