2Ö0 



crucible was wrecked during the process. The substance showed the 

 typical granular structure of the crystal con\erted into ji-spoduniene 

 with uudulatory extinction and a mean refractive index of: 1,518. 

 The specific weight at 25°, 7 0. was determined to be: (/4U= 2,309, 

 and to be 2,317 at 25°,1 C. 



§ 13. In all these experiments it was observed by us, that the 

 platinumcrucibles, in which the silicate was melted and solidified, 

 showed a strong deformation, which increased every time that the 

 experiment was repeated. As fig. 10 shows very clearly, this observed 

 deformation is of such a kind, that it always appears as a (//A/^sf/Zo??, 

 as if the silicate, like water, solidifies under a volume-expansion. 

 The values obtained for the specific volumes of the crystals 

 and of the qlass, seem however to make this explanation rather 

 improbable. We have tried by a series of systematic experiments to 

 find out, uiJien really this increase of the volume sets in, by measuring 

 the diameter of the crucibles, after their contents had been subjected 

 to different manipulations. In this way, we found, that by far the 

 largest deformation of the crucibles took place, at the transformation 

 of «-, into ,?-spodumene, which is accompanied by a volume-increase 

 of about 30"/,,. When the substance is then melted once more, and again 

 solidified, the deformation already present will be increased by the 

 thermal expansion of the mass, and because the liquid substance is 



Fig. 10. 



Deformation of the platinum crucibles after melting and solidification 



of the natural Spodumene. 



0. Original form of the platinum-crucibles. 



1. Pale yellow spodumene of Minas Geraës, Brasil. 



2. Kunzite of Sahato/ny-r alley, Madagascar. 



3. Dense Spodumene of Somerö, Finnland. 



4. Kunzite of Rhicon, California. 



