200 ANNUAL OF SCIENTIFIC DISCOVERY. 



phiiric acid. When the whole of this quantity has been intro- 

 duced into thi! boiler, the boiler is closed, and the temperature 

 raised to 1G0° C. by means of steam ; after 4 hours the action is 

 complete. The mixture is run ofl' into tubs, and the acid satu- 

 rated with linely powdered limestone. After separation of the 

 sulphate of calcium, the fluid is evaporated to20°B., clarified with 

 animal charcoal, and evaporated in vacuum-pans. An excellent 

 and beautiful glucose is thus obtained. — Mon. Scientif. 



NOTES ON THE MANUFACTURE OF SOAP. 



It. is a well-known fact that by an indirect method a potash 

 soap may be converted into a soda soap ; this is done by adding 

 to a boiling solution of a potash soap a very concentrated solu- 

 tion of common salt ; and it is generally taken for granted that 

 if enough of tiie latter has been added, the potash is replaced, at 

 least chiefly, by soda, and chloride of potassium is formtnl. Dr. 

 Oudemans has made experiments to ascertain how much of the 

 potash is replaced by soda, and finds that by the process, as exe- 

 cuted in a large scale and yielding excellent produce, only a lit- 

 tle more than half, to wit, 53.7 per cent, of potash is replaced by 

 soda, while 4G.3 per cent, of potash are left along with the other 

 alkali combined with fatty acids in the curd soap. — Jouini. f. 

 Prak. Chem. v. Erdmann, i., 1869. 



UTILIZATION OF CUROME-ALUM. 



The manufacture of aniline green and violet and of valerianic 

 acid gives abundant residues of chrome-alum. M. F. Jean pro- 

 poses to utilize the chrome-alum by pulverizing and mixing the 

 alum with 3 equivalents of carbon, and then decomposing at a red 

 heat in a retort of refractory earthenware. The I'eaetion occur- 

 ring may be thus expressed: KO, SO3, CroOa 3SO3 -|- 3C=3S02 

 -j-KO, S03-|-Cro03-|-3CO. The sulphurous acid is passed into 

 water or into a solution of carbonate of sodium, and the residue 

 boiled with water, to dissolve out the sulphate of potassium, which 

 may afterwards be obtained by crystallization. The sesquioxide of 

 chromium is then drained and calcined in order to get rid of all 

 the water, and although it is too dull for use in printing, it may 

 be used for the manufacture of bichromate of potassium. — Chem. 

 News. 



PURIFICATION OF BISULPHIDE OF CARBON. 



M. Millon purifies the bisulphide of carbon by first washing it 

 several times with distilled water, as in the purification of ether, 

 and then transferring it to a retort of large capacity containing 

 quick-lime. After 24 hours' contact the bisulphide is distilled otf 

 from the lime, and received in a flask partially filled with copper 

 turnings, which have been previously roasted to remove all traces 



