412 Scientific Intelligence. 
sided pyramid placed on the edges of the base, the angle between a 
. . 
face of the prism and one of the pyramid is 151° 22’. From this it 
follows that glucina is isomorphous with alumina, and its constitution is 
rundum; they are not attacked by acids except by concentrated and 
boiling sulphuric acid; bisulphate of potash, however, easily attacks 
them. The density of crystallized glucina is $-058, its atomic volume 
is 155; that of alumina is 160. In a second part of his memoir 
man points out a secund method of obtaining crystals in the dry way, 
namely, by precipitation. By causing lime in large fragments to act 
upon borate of magnesia, the magnesia is precipitated under the form 
of transparent crystals, sometimes large enough to be seen by the 
naked eye, and which are usually combinations of the cube and regu- 
lar octahedron. Their density is 3-636, and their hardness is almost 
equal to that of feldspar; they eonsist of pure magnesia. e peri- 
clase of Scacchi is magnesia containing 6 o er cent. of protoxyd 
manganese may be obtained crystallized. ‘The protoxyd of nickel is 
presented under the form of cubo-octahedra, of a green color, and 
cate of lime and leave a erystalline sand of Fe2Qs; FeO. 
lime is made to act upon a vitreous silicate of oxyd of titanium and 
monia, and 400 grammes of sand ahr i Rendus. 
eo, ) san = well dried.—Comptes , 
.. Researches on Populine.—Pirta has communicated the results of 
an investigation of populine which possess great interest. The consti- 
tution of populine was found to be represented by the formula CaoH22 
O1e-+4HO; at 100° C. it loses the 4 aq. and becomes anhydrous. 
One equivalent of populine + 2 eq. of water contain the elements of 
one eq. of salicin and one eq: of benzoic acid, as represented by 
equation CeoH2201s-+-2HO=C26HisOr4+CrelloOs. ‘ 
