Contributions to Experimental Chemistry, 371 



the means of procuriug tapirs from Sumatra, and no doubt 

 mastodons from Pegu. — {Conquest of Mexico ^ Sfc, ch. xi.) 

 There is, therefore, every human probabihty, if not certainty, 

 that this famous beast, the cause of so many erroneous con- 

 jectures, and so much speculation, is in existence in Assam or 

 Ava, or both. It is not a little remarkable that the first grinder 

 brought from an elephant country, possessed in 1283 by the 

 Moguls, should be that of a mastodon. Among the numerous 

 proofs of the Chinese-Mogul conquests in America, is, ** that 

 the practice of binding the feet in infancy, as in China among 

 some refined Tartars, is also found among the American 

 Indians." — (Yates and Moulton, p. 64.) 



Erratum, in our last Number, p. 152, line 8, for buskins, read sandals. 



Contributions to Experimental Chemistry, 



[Communicated by Mr. A. I. Walcker.] 



On Silicate of Soda. — A boiling solution of caustic soda dis- 

 solves pure (precipitated and dried) silica very readily. If as 

 much silica has been added as the liquid is capable of dissolv- 

 ing, the filtered solution, which reacts on test papers as an 

 alkali, assumes, by evaporation, a more and more tenacious 

 consistency. Being exsiccated at 242°, a pale yellowish mass 

 remains of a perfect glossy transparency, and consisting of 



Soda . . 5.351 (1 proportional) 



Silica . . 20.797 (8 ditto.) 



Water . . 19.350 



100.000 



This substance attracts humidity from the atmosphere, and 

 dissolves in water, though very slowly. Being heated to red* 

 ness, it loses its water, leaving a white spongy mass, which, 

 when heated before the blowpipe, requires an additional quan- 

 tity of carbonate of soda to be fused into a globule. The spongy 

 mass did not increase its weight by being exposed to the atmos- 

 phere for a few days. The solution of silica in caustic soda, 

 diluted with sufficient water to make the weight of the silica 

 amount to T^^th, -^^^ih, ^th, J-^th of the liquid, being very accu- 

 rately neutralized by sulphuric, muriatic, or acetic acid, is im- 

 mediately converted into a more or less dense and perfectly 



