SIE B. C. BEODIE ON THE CALCULUS OE CHEMICAL OPERATIONS. 853 



am far from believing that such is the true solution of this apparent anomaly. Such a 

 solution, although not absolutely precluded to us, is in the highest degree improbable ; 

 and the facts admit of an obvious and simple explanation on the hypothesis that chloride 

 of ammonium is decomposed, at the temperature at which its vapour-density is supposed 

 to have been taken, into equal volumes of hydrochloric acid and ammonia, of which very 

 satisfactory evidence has been given*. 



(2) Again, the density of the binoxide of nitrogen is 14"989, as determined by experi- 

 ment. If this be correct, 2 volumes of binoxide of nitrogen are decomposed into 1 volume 

 of nitrogen and 1 volume of oxygen ; whence, putting a'";;'"i|'^ as the symbol of the 

 binoxide, a.v^ as the symbol of nitrogen, and ^ as the symbol of oxygen, 



and 



2m =1, 



mi=l, 



^2=1, 

 and the symbol of the binoxide of nitrogen, as expressed by the factors a, v, |, is ol^)>%. 



If we now inquire, as before, whether any hypothesis as to the symbols of nitrogen 

 and oxygen can be made which shall be consistent with the fundamental assumption 

 that the symbol of hydrogen is expressed by one factor, we have, putting a''T"+'''> and 

 ^1+2, ^2(1+?,) ^g tijg general symbols of oxygen and nitrogen (Sec. VII. (2) and (8), 



and 



2m =l+2(?+;?), 



Now no positive and integral solution as regards m, g', and f. can be found which shall 

 satisfy the first of these equations. The above equation, therefore, which expresses the 

 relation which exists between the ponderable matter of the binoxide of nitrogen and its 

 elements, is incompatible with the expression of the symbols by an integral number of 

 prime factors, on the assumption that the symbol of hydrogen is a. 



The anomaly in the density of the binoxide of nitrogen was long since observed by 

 Laueent and Gerhardt, who discovered the empirical law of even numbers. But such 

 has been the influence upon the mind of chemists of an arbitrary hypothesis as to the 

 constitution of matter, and of an uncertain system of notation, that this anomaly, the 

 most singular exception known to the general laws of chemistry, is even now imper- 

 fectly recognized, and has never yet been submitted to any serious or adequate investi- 

 gation. 



(3) The following are the chief exceptions, real or apparent, to the law of prime factorsf. 



• See Pebal, Ann. Chem. Pharm., vol. cxxiii. p. 199. 



t See Latjbent's Cliemical Method, p. 81; Watis's Dictionary of Chemistry, vol. i. p. 469; Gekhardt, 

 Traite de Chimie, vol. i. p. 581, vol. iv. p. 897. 



MDCCCLXVI. 5 Z 



