Carbonates of alumina, glucina, iron, chromium, etc. 327 



The salt of glucina, which I used, was prepared by dissolvincr 

 glucina in a sligi.t excess of sulphuric acid and washing out tl.S 

 excess of acid with alcohol. Tlie glucina ustd had been freed 

 from alumina and iron, by dissolving it in sesquicarbonate of 

 fimmoniaand precipitating it by boiling, and by again dissolving 

 H in caustic soda and precipitating it by boiling. From tlie sul- 

 phate, thus obtained, the carbonate was precipitated by carbonate 

 of soda, in slight excess, and analyzed in the same way as the 

 carbonate of iron. The wash- water from the ignited glucina 

 contained no glucina, no glucinate of soda having been lormed. 

 Analyses of two preparations gave the following results: 



60 lOu-OO 100 00 100 00 10000 



If glucina be regarded as a protoxyd, as it has been by some 

 chemists, the above results would correspond to the formula, 

 3G0, CO, (calculated, G.=4-7, 63-40 GO and 36-60 CO,). 

 5. Carbonate of the sesquioxyd of Uranium. 



The precipitate, produced by carbonate of potash in nitrate of 

 (Cranium, after being washed with cold water and dried in the 

 ■''i^ has, according to Ebelmen,* the following composition: 

 366 KO, 8-87 CO,, 81-98 U3O3 and 10-49 HO; and is probably 



The precipitates, which I have examined, were precipitated, 

 some from the sulphate, others from the nitrate of uranium, by 

 carbonate of soda, in as small excess as possible. The general 

 pode of analysis, described under carbonate of iron, could not 

 oe employed here. There would be a variable mixture left in 

 the bulbed tube, after ignition, consisting partly of uranate of 

 Soda (formed when sesquioxyd of uranium is ignited with car- 

 bonate of soda) and partly of proto-sesquioxyd of uranium. 

 ■^he substance was, therefore, ignited in a stream of dry hydro- 

 gen, free from carbonic acid, and the carbonic acid absorbed by 

 ^ weighed soda-lime tube.f In this way, the sesquioxyd 13 



j^t^Tjus method of aWbinJ^ 



t:!-^^'V%11^ 



^\ This has the advantage that it absorbs a large part ot the M 



