426 Miscellaneous Inielligence. 
water 31-7, or a simple hydrate of magnesia. He has made copies of 
medals, like those of plaster, from magnesia thus hardened under water. 
Balard’s magnesia, calcined at a red heat, he says, has hydraulic qualities 
which are manifested with a rapidity that is most admirable; though 
when calcined at a white heat, the property is almost wholly Jost. A 
mixture of pulverized chalk or marble and magnesia in equal parts fur- 
nishes with water a paste which is a little plastic, but which after being 
some time in water affords products “ of extreme solidity,” and he pur- 
poses to use the mixture for making busts of artificial marble. Plaster 
mixed with magnesia diminishes the hydraulic properties. 
On calcining dolomites rich in magnesia at a low temperature, below 
red heat, the powder solidifies under water very rapidly, and gives @ 
stone of a hardness which is “really extraordinary.” If calcined at a 
mite is heated to redness, and all the lime is reduced to .the state of 
guicklime the hydraulicity is lost. In the above results, the magnesia 18 
the hydraulizing ingredient, it soldering together the particles of carbon- 
led 
. 
ate of lime exactly as in the mixture of magnesia and marble dust. 
5. Meteorites of Aumale, Algeria.—A fall of meteorites took place on 
the 25th of August last between 11 and 12 m., in Algiers, in the district of 
from ps place of fall of the former, in 0° 20/ E, and 36° 27! Ms This 
The thin crust of the meteorite is dull black, slightly rugose. ier 
he me @ are planes, nearly flat, which are striated evidently by 
the friction of the two surfaces.—J , Feb. 15. . 
6. Large mass of meteoric iron—A mass weighing 82874 Ibs. (3,750 kil.) 
was received last year at the British Museum from Australia.—Zb., Aug: 10- 
ec magles 
