OF ARTS AND SCIENCES. 17 



ate, because it melts below 100°. The second sodic zincate was ob- 

 tained from the alcoholic washings, which were mixed, and allowed 

 to stand in a corked flask, when after some time, which varied from 

 a few hours to several days, white crystals were deposited on the sides 

 of the flask, which gradually increased iu quantity. The formation of 

 these crystals did not occur invariably, but they could often be made 

 to appear by adding more alcohol to the washings. This compound 

 deposited from the alcoholic washings does not fuse even at 300°, anil 

 we shall call it infusible sodic zincate. 



Analysis of the Fusible Sodic Zincate, Zn 3 6 Na 4 H., . 1 7 II 2 0. 



This substance is the principal product of the reaction, forming, as 

 nearly as we could estimate, over 90 per cent of the total product. 

 Since both water and alcohol decompose it, a further purification 

 seemed impossible, and we were obliged to analyze it as it was obtained 

 by the precipitation with alcohol, simply drying it by pressure between 

 filter paper under heavy weights. 



The method of analysis, which we adopted after trying several 

 others, consisted in dissolving the substance in dilute sulphuric acid, 

 and precipitating the zinc by means of a measured quautity of a stand- 

 ard solution of sodic carbonate. The zinc was weighed as oxide. 

 The filtrate was acidified with sulphuric acid, evaporated to dryness, 

 weighed, and then the amount of sodium calculated after subtracting 

 from the total weight of the sodic sulphate the weight of sodic sulphate 

 corresponding to the sodic carbonate added. 



I. 0.4720 grm. of the substance gave 0.1744 grm. of zincic oxide 



and 0.2080 grm. of sodic sulphate. 

 II. 0.6420 grm. of the substance gave 0.2302 grm. of zincic oxide 

 and 0.2718 grm. of sodic sulphate. 0.8802 grm. of substance 

 from the same preparation lost at 240° 0.3920 grm. of water, 

 and the dried product gave on heating with chromic oxide in 

 a stream of dry oxygen 0.0342 grm. of water. 

 III. 0.9682 grm. of the substance gave 0.3370 grm. of zincic oxide 

 and 0.3992 grm. of sodic sulphate. 0.8770 grm. of substance 

 from the same preparation lost at 240° 0.4021 grm. of water. 



VOL. XXIV. (N. S. XVI.) 



