198 - ANNUAL OF SCIENTIFIC DISCOVERY. 



* 



ether, in the manner already pointed out by Hoffman. The results 

 of this investigation are interesting from the prospect which they 

 afford of obtaining the ethyl-ammonias as an article of commerce, 

 at a reasonable price, and in comparative abundance. Amer. 

 Jour. Science, July, 1870. 



CHEMICAL BREVITIES. 



Preparation of Anthracene. Dr. J. Oessert. That portion of 

 the distillation of coal tar commonly called green grease, and 

 used as wagon and cart grease, is, according to the author, the 

 material of coal tar which contains anthracene, and consists chiefly 

 of a heavy oil, uapthaline, and about 20 per cent, of anthracene, 

 Avhich, however, is contained in coal tar only to the amount of 

 from three-fourths to 1 per cent. This semi-fluid grease is first 

 placed in a centrifugal machine, in order to expel mechanically as 

 much as possible of the oil; the residue is heated to 40 and 

 pressed, preferably between hot plates. The cake thus obtained 

 (crude anthracene, containing 60 per cent, of that substance) is 

 purified by boiling with light tar oil, (coal-tar naphtha) or with 

 petroleum naphtha. The pasty mass is again placed in the cen- 

 trifugal machine to remove the last traces of heavy oil, and the 

 material is next submitted to sublimation. In order to test the 

 "green grease" for the quantity of anthracene, from 5 to 10 

 grams of that substance are taken, placed between folds of filter- 

 ing paper, and pressed between hot plates; the remainder of the 

 substance is repeatedly boiled with alcohol, washed with cold 

 alcohol upon a filter, dried and weighed. The fusion point of the 

 mass should be as near as possible 210. The author says that 

 sulphide of carbon is not well suited for the preparation of anthra- 

 cene, on account of the too ready solubility of anthracene in that 

 fluid. 100 parts of alcohol dissolve, when cold, 0.6 part of anthra- 

 cene ; 100 parts of cold benzole dissolve 0.9 part anthracene ; 100 

 parts sulphide of carbon dissolve 1.7 part anthracene. Chemical 

 News. 



Preparation of Bromide of Sodium. According to M. Cas- 

 telhaz (" Comptes Rendus") the best plan is to prepare, first, 

 bromide of ammonium, by causing bromine to fall, drop by drop, 

 into dilute pure liquid ammonia contained in a series of 

 Wolff's bottles, in order thus to prevent the loss otherwise inevi- 

 tably resulting from the volatilization of the products formed by 

 the great heat disengaged by the union of the bromine and ammonia. 

 The liquids, after saturation, are evaporated in a cast-iron retort, 

 to which an earthen-ware receiver is fastened, wherein are col- 

 lected the vapor of water, any excess of ammonia and some 

 bromide, of ammonium, which is accidentally carried over. The 

 bromide of ammonium thus obtained is converted into bromide 

 of sodium, by being mixed with pure carbonate of sodium, and the 

 application of sufficient heat to volatilize and sublime the carbon- 

 ate of ammonium formed by the reaction. This mode of prepara- 

 tion yields, after re-solution of the bromide in water and evapora- 



