438 Prof. Odling on the Natural Groupings 



menstrua. One modification of titanic acid is soluble in dilute 

 acids, alkalies, and probably in water. One modification of 

 stannic acid is soluble in dilute acids, alkalies, and sparingly in 

 water. From soluble borates, silicates, titanates and stannates, 

 the hydrated acids are precipitated by the addition of nearly any 

 other acid however feeble. The four elements form correspond- 

 ing bisulphides. Silicon and tin give origin to complex sulpho- 

 chlorides, between two of which a correspondence is manifested : 



Si3 s^cin siss^ci^ 



SnSS^ClM SnS^CP^. 



Tin, with the atomic weight 117'6, has for its atomic heat 

 6".5, which number consequently pertains to all the hitherto ex- 

 amined members of the first four groups. The atomic volume 

 of tin is 202. 



The four groups already considered comprise all the non- 

 metallic elements, with the exception of hydrogen and carbon. 

 Hydrogen appears to occupy a neutral position, and to stand as 

 the representative of both chlorous and basylous elements. In 

 very few hydrogenized bodies, however, can the hydrogen be 

 replaced with equal facility by chlorine, and by zinc or potas- 

 sium. As a general rule, we find that the facility of replacement 

 by a basylous metal is directly, by chlorine inversely, as the de- 

 gree of oxidation of the compound. Thus in the phosphorus 

 series we have the following derivatives : — 



CP P . Phosphorous chloride, 



CP PO . Phosphorus oxychloride. 



Km PO^ . Hypophosphitc of potash, 



K^H P03 . Phosphite of potash, 



K3 PO* . Phosphate of potash. 



Again :- 



C^ H^ AgO^ . Benzoate of silver, 

 C^ H* Ag^O^ . Salicylate of silver. 



Moreover, we are acquainted with tetrachlorethylene (and 

 tetrachloraldehyde, Laurent), but only with trichloracetic acid : — 



02 01^* 

 C^ Cl^O 

 C2 HCF 02 



and so in a gi-eat number of other instances. Seeing that the 

 acid character of a body is dependent upon the facility with 

 which its hydrogen can be replaced by a basylous metal, it seems 

 that oxygen is justly entitled to its Lavoisierian appellation. 

 Carbon appears to be an element altogether sui generis, though 



