913 
Very remarkable is the high specifie gravity of the cadmium- 
metasilicate. 
Melting-temperature 
in °C. 
1800° 
1700° 
1600° 
1500° 
1400° 
1300” 
-1200° 
9 24 40 55 65 87 112 137 
Be Mg Ga Mn Zn St Cd Ba 
Atomic Weight 
of the Metal. 
Fig. 2. 
With respect to the melting-points of the meta-silicates (fig. 2), it 
may yet be remarked, that those of the Ca-, Sr-, and Ba-silicatés 
increase in an almost rectilinear way with increasing atomic weight 
of the corresponding metal, while those of the Mg-, Zn-, and Gd- 
salts appear to decrease in an analogous way with increasing atomic 
weight of the metal. BeSiO, on the one side, MnSiO, on the other 
side seem, however, to be quite apart from both these homologous 
groups. 
For the ortho-silicates the available data are too few, to obtain 
an analogous classification with any certainty. In every case evi- 
dently the meltingpoints of Sr,S7O, and Ba,S¢O, are probably situated 
in the vicinity of 2200° C., while that of e,SvO, must be even 
much higher. In connection with this it would be interesting to in- 
vestigate, if perhaps Be,SiV, does not possess further properties, 
which would make it recommendable as an extremely refractory 
material. 
Groningen, October 1915. University-Laboratory for Inorganic 
and Physical Chemistry. 
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