896 
Chemistry. — “Investigations in the Field of Silicate-Chemistry. 
IV. Some data on the Meta- and Ortho-Silicates of the bivalent 
Metals: Beryllium, Magnesium, Calcium, Strontium, Barium, 
Zinc, Cadmium, and Manganese.” By Prof. Janerr and 
Dr. Van KLooster. 
(Communicated in the meeting of Nov. 27, 1915.) 
§ 1. In connection with the investigations into the erystallisation- 
phenomena of complex, molten silicate-magmas, as they were com- 
menced in this laboratory, but stopped for some time since August 
1914, — it was necessary for our purpose to study in the first 
place again the solidifying phenomena of the pure silicates of the 
alealine earths and of zine, cadmium, and manganese. 
The data about the melting- and solidifying-points and about 
several properties of the just named substances found in literature 
are rather discordant and often contradictory. As far as the silicates 
of calcium and magnesium are concerned, definite results can be 
said to have been obtained now in the very accurate investigations 
from the Geophysical Laboratory in Washington’). Some of the 
data obtained there are once more reviewed at the end of this note 
for the purpose of comparison with those established here. 
About the melting- and solidifying-points of the silicates of the 
other bivalent metals: Sr, Ba, Zn, Cd and Be, there has not yet been 
obtained any certainty, while about those of Mn, only a few, rather 
uncertain data are available. 
Indeed several investigations *) of these silicates have been published; 
but the experimental methods were in all those cases such, that no 
reliable results could be expected, as will appear clearly in the 
following pages. 
For without any exception, cooling-curves were always used in 
these determinations, which, — as has been already repeatedly 
proved, and is again stated here by us, — can never give any 
reliable result in the case of si/icates, not even in the most favour- 
able circumstances. Furthermore in not one of these cases sufficient 
attention was given to the preparation of completely pure products, 
nor to the complete chemical homogeneity of the molten substances; 
neither was a reducing atmosphere avoided with respect to the 
1) Arcen, Warre and WricHt, Amer. Journ. of Science 21, 89. (1906); ALLEN, 
Wricut and CLEMENT, ibid. 22, 385. (1906); A. L. Day and SHEPHERD, Amer. 
Journ. of Science 22, 265 (1906); ALLEN and Warre ibid, 27, 1. (1907); SuEp- 
HERD and RANKIN, ibid. 28, 293. (1909). 
*) SreiN, WALLACE, LEBEDEW, Zeits. f. anorg. Chem. 55, 63, 70. See the lite- 
rature given further-on. 
