873 



Temperature 



in M. V. 



9950 Idem. 



9962 About 10 7„ glass; further as mentioned above. 



9985 About 50 "/„ glass; imbedded bisilioate and needles. 



9990 About 70— 807n glass; needles ofap|)areii(lv impure metasilicate 

 ni) = 1.57;. 

 10005 About 90 V„ glass; needles with 77£,= 1.56 or 1.57. 

 10040 Almost all glass (n = 1.536); locally a tew needles. 



Preparation N". 6. Analysis: 75.7 7,, ,SV(A, (=60.7 Mol. Proc). 



Temperature 

 in M.V.: 



9930 Felty aggregations of metasilicate, intergrown with much 



bisilicate. 

 ■9990 About 5 7„ glass; metasilicate with ??/)=1.57. 

 10030 About 80 7„ glass ; felty birefringent needles. 



We are of opinion, that in accordance with these results, the field, 

 in which the bisilicate can exist in colitact with a binary li(piid, 

 can be indicated as done in fig. 1 ; the compound must melt at 

 1032° C. under dissociation into metasilicate, and give a binary liquid 

 of slightly varied composition. However, it seems, that no pure 

 metasilicate is deposited, but a very dilute solid solution of the 

 bisilicate in it; this we may conclude from the fact, that the refractive 

 indices of the needles are always somew^hat less than those of the 

 pure compound. 



§ 10. The third possible compound, existing in contact with its 

 binary liquid, the ortkosilicate : Li^SiO^, was prepared in quite the 

 same way by heating of the finely divided, thoroughly mixed 

 components. Although the mixture, in composition identical with 

 the compound, could also in this case be melted with a blast, if in 

 small quantity, it was necessary to keep the molten mass at 1500° C 

 for some time, to be sure, that practically all carbondioxide is 

 expelled. Rut then some Li^O volatilizes, and thus the chemical 

 composition must be corrected again and again, till the required com- 

 position is reached. If, as is the case in the Flffcher-invuncv, thci-e 

 is some watervapour present, the mass obtains afterwards a very 

 disagreeable odour of silicohjdrogens. It seems, that the llame-gasea 



56- 



