-/. M. Ordway — Waterglass. 4^1^ 



of cake almost entirely soluble and containing 38 p. c. of 

 10Li 2 O23Si0 2 . 



13. 50 g. of a 7 p. c. Li„Si0 3 solution heated almost to the boil- 

 ing point gave an abundant precipitate of which about five-sixths 

 redissolved on standing two days. 



14. 47 g. of a liquor holding 21 p. c. of 10Li s O-23SiO„ heated 

 to 90° C, made a hard mass that could not be got out of the 

 beaker. On cooling it liquefied again and the next day showed 

 very little sediment. 



Rubidium Silicates. 



From the chemical similarity of the light metals we might 

 suppose that rubidium would afford a series of silicates like 

 those of potassium. But positive proof is better than analogi- 

 cal conjecture. And verification was possible because happily 

 the lepidolite that furnished material for the lithium experi- 

 ments contained rubidium also. Some rubidium hydroxide 

 was made by decomposing the sulphate with baryta, and some 

 by the better method of burning the bitartrate and boiling the 

 resulting carbonate with lime. A clear solution w T as evapor- 

 ated in a nickel crucible till it contained 21 p. c. of Rb 2 0. 

 Nearly enough silicic acid hydrate being added to make a 

 monosilicate, the boiling down was continued till the Rb 2 Si0 3 

 amounted to 82 p. c. The thick liquid on standing showed no 

 disposition to crystallize. Diluted and heated with more silica 

 it took up sufficient to form a bisilicate. Precipitation with 

 alcohol gave more silicious compounds. 



15. 100 g. of a solution containing 16*5 p. c. of 3Rb 2 OlOSiO 

 with 35 cc of alcohol gave a cake weighing 16 g. and contain- 

 ing 71 p. c. of Rb 2 0'4Si0 2 . This dissolved in twice its weight 

 of water. 



The mother liquor with 40 cc of alcohol let fall a curd 

 weighing 2*5 g. which showed 71 p. c. of 2Kb 2 O7Si0 2 . 



16. 160 g. of 21 p. c. 4Rb 2 O7Si0„ with ]50 co of alcohol 

 gave a clear liquid precipitate weighing 43 g. It contained 45 

 p. c. of 10Rb 2 O23Si0 2 . 



17. 92 g. of liquor containing 15 p. c. of 10Rb 2 O29Si0 2 with 

 22 ce of alcohol produced 22 g. of cake not entirely soluble. The 

 soluble part amounted to 58 p. c. of 10Rb 2 O46Si0 o . The resi- 

 due consisted chiefly of 1-5 g. of SiO„. 



18. 45 g. of 15 p. c. 4Rb 2 O9Si0 2 with 30 g. of 11 p. c. LiCl 

 let fall 4 g. of cake, not completely soluble. The soluble portion 

 amounted to 29 p. c. of 17(Rb 2 O2Si0 2 ) + 14Li 2 OSi0 2 . 



Action of Ammonia on Waterglass. 



When caustic soda is poured into a strong waterglass solu- 

 tion it produces a momentary cloud ; lithium hydroxide gives 



