81 
ArtiFic1aL Propuction or CELEsTITE.—Strontium sulphate, 
_ or the mineral Celestite, may be produced artificially, as in the 
case of Barytes. The procedure of Manross and Macé is 
especially to be preferred. M. Behrens has shown that by 
placing under the microscope a drop of liquid sulphuric acid, 
containing a little strontian sulphate, delicate slender crystals, 
crossing each other, can be seen, like those of barytes, only of 
larger size, and less transparent. M. Frémy has obtained 
erystals of Celestite by a slow double decomposition, by 
operating upon solutions of different densities, separated merely 
by a porous diaphragm, or a sheet of bibulous paper. 
The method followed by Manross (Ann. Ch. Pharm. t. 
LXXXII., p. 348) to obtain strontium sulphate is by melting in 
a crucible, a mixture of potassic sulphate and strontium chloride. 
After washing the product, a crystalline powder is obtained, 
composed of small crystals of Celestite, identical both in form 
and composition with the natural mineral Celestite. 
Macé’s process is by bringing together two attenuated 
solutions, one of strontian nitrate, the other of ferric sulphate, 
by means of a wire plunged into each solution. Under such 
conditions the contact of the two salts causes them to act upon 
each other with extreme slowness, the result being that the 
Celestite crystallizes as it is forming.* 
Both Celestite and Barytes are classed as concretionary and 
vein minerals: all the chemical synthetic methods prove the 
fact, and coincide in explaining the way in which these minerals 
are formed in nature. 
Professor J. D. Dana mentions in his “System of Miner- 
alogy, 6th edition, New York,” that Celestite has been obtained 
_ by Dr Sullivan in lamellar crystals from solution in water at a 
_ temperature of 300° Cent. by fusing a mixture of gypsum and 
common salt, and treating the residuum with water. 
The salts of Baryta are poisonous; those of Strontia are 
innocuous. Strontian sulphate (Celestite) has now quite super- 
seded the former as an efficient means of clearing sugar when 
boiling, in the process of sugar refining. 
* Macé, J. pour Chém. t. XXXXI. p. 825. 
