ON THE THEORY OF TYPES IN CHEMISTRY. 125 
illustrated by sulphur in its ordinary state, which I showed is to be 
regarded as a triple molecule S,, (or 8, = 4 volumes) and referred 
sulphurous acid SO, to this type, to which also probably belongs 
selenic oxide. (At the same time I suggested that the odorant form 
of oxygen or ozone was possibly O,.) Wurtz in his memoir, publish- 
ed in 1855, adopts my view, and makes sulphur vapour at 400° C the 
type of the triple molecule. I farther suggested (American Journal 
of Science, v. 408, vi. 172,) that gaseous nitrogen is NN, an 
anhydrid amid or nitryl, corresponding to nitrite of ammonia, (NO,, 
NH,0)— H,0, = NN. This view a late writer attributes to 
Gerhardt, who adopted it from me, (Ann. de Chimie et Phys, |x. 381.) 
May not nitrogen gas, as I have elsewhere suggested, regenerate 
under certain conditions, ammonia and a nitrite, and thus explain not 
only the frequent formation of ammonia in presence of air and reduc- 
ing agents, but certain cases of nitrification ?* 
I endeavoured still further to show that hydrogen is to be looked 
upon as the fundamental type from which the water type is derived 
by the replacement of an atom of H by the residue HO,, (American 
Journal, viii. 93.) In the same way I regarded ammonia as water in 
which the residue NH replaced O,. 
I have always protested against the view which regards the so- 
called rational formulas as expressing in any way the real structure 
of the bodies which are thus represented. These formulas are 
invented to explain a certain class of reactions, and we may con- 
struct from other points of view, other rational formulas which are 
equally admissable. As I have elsewhere said “ the various hypotheses 
of copulates and radicals are based upon the notion of dualism, which 
has no other foundation than the observed order of generation, and 
ean have no place in a theory of science.’ All chemical changes 
are reducible to union (identification,) and division (differentiation). 
When in these changes only one species.is concerned, we designate 
the process as metamorphosis, which is either by condensation or by 
* The formation of a nitrite in the experiments of Cloez appears to be independent of the 
presence of ammonia, and to require only the elements of air and water (Comptes Rendus.) 
Some experiments now in progress lead me to conclude that the appearance of a nitrite in 
the various processes for ozone, is due to the power of nascent oxygen to destroy by oxydae 
tion the ammonia generated by the action of water on nitrogen, the nitrous nitryl ; so that 
the odor and many of the reactions assigned to ozone or nascent oxygen are really due to 
the nitrous acid which is set free when the former encounters nitrogen and moisture. On 
the other hand, nascent hydrogen, which readily reduces nitrates and nitrites to ammonia, 
by destroying the regenerated nitrite of the nitryl, produces ammonia in many cases from 
atmospheric nitrogen. 
