Mr Emmet on the Solidifivatioii of Raw Gypsum. 73 



placed on a filter, and a cold solution of carbonate of potassa 

 poured over it. The result was the rapid solidification of the 

 crude mineral, and an evident diminution of the alkali. 

 Upon repeatedly returning the same solution through the filter, 

 turmeric paper ceased to indicate the presence of potassa, and 

 re-agents showed that sulphate of potassa had taken its place. 

 In this manner, a saturated solution of the latter salt may be 

 soon obtained, yet, as has been already stated, a further exami- 

 nation proves, that the sulphate of potassa is not capable of con- 

 tracting a permanent union with the gypsum. 



Further inquiry will, no doubt, lead to the detection of salts 

 better adapted to the development of this property than those 

 here noticed, but the cheapness of carbonate of potassa seems 

 more likely to recommend its use for practical purposes, pro- 

 vided it shall be found that the sohdification of raw or effete 

 plaster, by the process here indicated, equals, in durability, 

 that which has been recently burnt. Gypsum, it is well known, 

 requires judicious treatment, in order to fit it for taking casts, 

 and unless carefully defended from moisture, will soon lose its 

 valuable property. The process of burning may, moreover, not 

 always be convenient, and, in this case, a solution of carbonate 

 of potassa, or, for common purposes, the ley from wood ashes, 

 will always enable the operator to effect rapid solidification, and 

 as far as I have observed, it is perfect. — Amer. Journ. of 

 Science ^ Arts, vol. yxiii. No 2. p. 210, 



ON THE PHYSIOGNOMY OF SCANDINAVIA*. By ProfcSSOT 



Hausmann. 



The united impression which the mountains and valleys, the 

 woods and meadows, the river and lakes, and all other parts 

 of a country, make upon our feelings, may be called its charac- 

 ter or physiognomy. We feel a greater attraction for one coun- 

 try, and a less attraction for another, just as regards the physio- 

 gnomy of men; and are equally unable to account for these 

 sensations. As in the aspect of countenances, it is not the regu- 

 larity and harmony among the several features which invariably 

 • Translated from the German original by George F. Hay, Esq. 



