Proceedings of the Polytechnic Association. 991 



cannot exist in a separate itate, bnt two sncli compound atoms or 

 atomoids, v;ill unite like two atoms of nitrogen, to form a molecule. 

 In this manner the peroxjd of nitrogen is shown to be also mona- 

 tomic, because two atoms of the dyad oxygen have a substitution 

 value of four, and exceed l)y one that of nitrogen. In one case tlie 

 value of the radical is expressed by 3 — 2, and in the other by 4 — 3. 

 Kitrous anhydride and nitric anhydride are formed on the vrater type 

 by the fAlition Cif an atoin of oxygen to two of these radicals respect- 

 ively. The h.'V.-est oxyd oi nitrogen, laughing gas, is an inert body^ 

 liaving neither alkaline nor acid characteiistics. Its atomoid contains 

 two atoms of nitrogen and one of oxygen, and its combining power 

 is expressed by 2X3 — 2. Should it hereafter be foun.d to act as a 

 radical, it is here predicted that its value v\'ill be tetratomic. 



An example bearing still more directly on the question of the 

 atomicity of nitrogen is that of cyanogen, an atomoid of Avhich con- 

 tains an atom of carbon n2i and an atom of nitrog<,'n (14). If these 

 two atoms meet on equal terms, either the 'carbon atom beonies a 

 triad, or the nitrogen atom a tetrad. On the other hand, if it is 

 {tesumed tliat both elements retain their normal saturating power, car- 

 bon as a tetrad f.nd nitrogen as a triad, we satisfact(n'ily account for 

 its monaton^iic substitution value wliich is expressed by 4 — 3. In its 

 general behavior this radical resembles the halogens ; tlm.s presenting 

 an apparent anamoly in the f.)rniation of a compori:"d hasiiig power- 

 ful electro-negative characteristics found in neitlier <>i' its cxinstiiuents, 

 and proving tliat the predominance of atomicity in an eloaient does 

 not necessarily inqxart to the body of which it forms a part any of its 

 chemical functions; in other,. words, that the atom of lowest combin- 

 ing value is not merged in that of the highest, but that, as between 

 the two, the mxerging is mntustl ; the result being an absolutely new 

 body bearing no resemblance to its constituents in a separate state, 

 and exhibiting only that relation to them wdiicli arises irum the 'law 

 of differential atomicity. This huv was expressed in a paper read by 

 me before this Association Jn 1866, as follows : " Tlie atomicity of a 

 torso (tlnit i^ an imperfect body having no separate* existence) or of a 

 radical containing one atom of an element nnited to one or more 

 atoms of another element is eonal to the diiference between the nor- 

 mal saturating povrer of its components.""" 



It is diflieult to trace all the steps of the resulting atomicity in 



*Dr. Anrr. Kckiile ofEiIaugon, Bavaria, wa-tlie first to explain why certain complex chemical com- 

 pounds of the fame ultimate composition often ilificr in atomicity. 



