94 T. S. Hunt on Chemical Classifications. 



The first corresponds to iron and the allied metals in their ordi- 

 nary condition, while the second appears to be connected with 

 M 2 which in permanganic and perchromic acids, is found equiv- 

 alent to CI. The passive state of iron induced by electricity and 

 many other agencies, suggests itself as analogous to that of insol- 

 uble chromium. # 



The constitution of gaseous nitrogen as I have shown in the 

 previously quoted paper is probably NN, (N = 7 — = 8,) corres- 

 ponding to the two volumes of vapor, and differs in the conden- 

 sation of its molecule from its congeners, phosphoric and arsenic 

 in their ordinary condition. May not the allotropic condition of 

 phosphorus alluded to by Berzelius, be an analogous molecular 

 condition of this substance ? The question would be solved by 

 a determination of its density in that state. 



The difference in the specific densities of the two crystalline 

 forms of carbon, seems to indicate that the diamond has double 

 the atomic weight of graphite, and there are reasons for suppo- 

 sing that charcoal is a still higher polymeric modification of the 

 elementary carboii.f If these suggestions lead to an explanation 



* Those substances which are considered elementary may change their equivalents 

 at the same time undergoing a corresponding change in their density, and as we ob- 

 tain from the ordinary equivalent and density an idea of u the volume of the atom? 

 we say of those forms having an increased density and a corresponding increase of 

 equivalent (so that the atomic volume remains unchanged), that two or more of the 

 ordinary molecules have united in one. This is illustrated in the case of sulphur, 

 and also in those^ salts of mercury and copper where these metals unite in twice 

 their ordinary equivalents. In the one mercureeum (Gerhardt) with an atomic weight 

 of 100, (H=l) is the equivalent of H ; in the other, mere* rattan (G.) =200, enjoys the 

 same power in combination. So of Cu cupricu?n, and Cu 2 cuprosum, atomic volume 

 with it4 are cases in point, and we might Bay that the atom of iron has one-third the 

 commonly received equivalent, and that Fe(3 is nude up of two and Fe of tliree 

 atoms of elementary iron. The so-called element- may then possess different atomic 

 weights which enjoy a simple relation to each other, and in these different states ex- 

 hibit very different characters. When we speak of one of these as containing two or 

 three atoms of another form, condensed in one, it is only an expression, in accord- 

 ance with previously existing ideas. We can no longer attach to the atomic weights 

 of the supposed elements, an absolute value, and thus one of the characters which 

 served to distinguish them from known compounds is rendered of no importance. 



f The experiments of Mr. Hatchett, (Philos. Trans., 1805,) show that charcoal, by 

 the prolonged action of nitric acid, is dissolved and converted into a soluble, astrin- 

 gent, azotized body, described by him as artificial tannine, which has all the char- 

 acters of an organic substance of a pretty high equivalent. As the action of oxyd- 

 izing agents seldom if ever results in the production of a body higher in the orgam* 

 scale than the parent substance, and as we can scarcely expect the polymorph' > sl> 

 of elementary carbon under the circumstances to form an organic body, I am led to 



suspect that charcoal is a species of anhydrid derived from cellulose, possessed of 



a high equivalent, and Capable under the action of an acid of taking up the elements 

 of water to form a substance which by the fixation of nitric acid and oxydation, pro- 

 duces the substance in question. . , 

 The researches of Johnson upon paracyanogen, which is in fact a sort of azotized 

 char* d, are worthy of consideration in this connection. The body derived from 

 charcoal h not, bo far as I am aware, rec ved any attention since the experiment- 

 of Mr. Hatchett; I have commenced an examination of it, and hope before long to 

 determine something with regard to its real nature. 



X This Journal for Nov., 1847, p. 405. 



