XX.] THEORY OF TYPES IN CHEMISTRY. 467 



are as truly neutral salts of a particular type. Thus the bibasic 

 and tribasic phosphates are to be looked upon as sub-salts, 

 which sustain the same relation to the monobasic phosphates 

 that the basic nitrates bear to the neutral nitrates. He suc- 

 ceeded in preparing two crystalline sub-nitrates of lead and 

 copper, having the formulas N0 5 ,M 2 2 ,HO (tribasic), and 

 N0 5 ,M 4 04,H 3 03 (heptabasic), both of which retain their water 

 of composition at 392 F. 



The compounds of sulphuric acid are : 1 . The true monobasic 

 sulphate, S 2 6 MO, corresponding to the Nordhausen acid and 

 the anhydrous bisulphates ; 2. The ordinary neutral sulphates, 

 S 2 6 ,M 2 2 ; 3. The so-called disulphates, S 2 6 ,M 4 4 corre- 

 sponding to the glacial acid of density 1.780 ; 4. The type 

 S 2 6 ,M 6 6 , represented by turpeth mineral ; 5. The so-called 

 quadribasic sulphates, S 2 6 ,M 8 8 . The copper-salt of this octo- 

 basic type still retains, moreover, 6 HO at 392 F. (Gerhardt 

 on Salts, Jour, de Pharmacie, 1848, Vol. XII. ; American 

 Journal of Science, VI. 337.) Without counting the still more 

 basic sulphates described by Kane and Schindler, we have the 

 following salts, which, in accordance with Wurtz's notation, 

 correspond to the annexed radicles : 



1. Unibasic S 2 HO T = S 2 5 monatomic. 



2. Bibasic S 2 H 2 O 8 = S 2 O 4 diatomic. 



3. Quadribasic S 2 H 4 O 10 = S 2 2 tetratomic. 



4. Sexbasic S 2 H 6 12 = S 3 hexatomic. 



5. Octobasic S 2 H 8 14 = S 2 O 2 octatomic. 



It is easy to apply a similar reductio ad absurdum to the 

 radicle theory in the case of the oxychlorides and other basic 

 salts, and to show that the radicles of the dualists are often 

 merely algebraic expressions. (See further my remarks in the 

 American Journal of Science, VII. 402-404.)* 



* Those who are familiar with chemical literature will remember an amus- 

 ing jeu d" esprit of Laiirent's, in which he invited the attention of the advo- 

 cates of the radicle theory to a newly invented electro-negative radicle, 

 eurhizene. (Comptes Rendus des Travanx de Chimie for 1850, pages 251 

 and 376.) A late writer in the Chemical News (Vol. I. page 326) proposes, 

 as a new electro-negative radicle, under the name of hydrine, the peroxide 

 of hydrogen H0 2 , the eurhizene of Laurent. 



