864 



/öiV 



r 



WO' 



nw' 



Cl -Tndymiot 



<s7<' 



+ 

 Bislllkaet 



SlO,.' .1 A' IS io :.i X' 33 >Ö M M .0 oV 6i 7C ló dC t>i 9C 9S 

 C^Mnaislitïtua l/l //h-Zi/cUnüiivcf/i/eyi 



1HXI' 



/JPÖ' 



/iW" 



HOC' 

 l-i,0. 



Fig. 1. 



Temperatuur = Temperature. (Jristobaliet = Cristobalite. Tridymiet = Tridymitc. 



Bisilikaat = Bisilicate. Vaste oplossing van Bisilikaat in Metasilikaat = Solid solutions 



of Bisilicate in Metasilicate. /Ï-Kwarts = /^-Quartz. Samenstelling in Molekuul- 



procenten = Composition in Molecule-procents. Orthosilikaat = Orthosilicate. 



of 0.47o C'Oiild be stated. We finally obtained a temperatnre-time- 

 curve, in which the euteetio effect had disappeared, starting with 

 a mixture, which showed a small excess of the lithiumoxide ; the 

 meltingpoint was now at 12598 M.V. (corr.) corresponding with 

 1255°, 5 C. This temperature we must consider as being the true 

 meltingpoint of the orthosilicate, with an uncertainty of about 



