Chemistry and Physics. . 423 
8. Preparation of pure Barytic oe and Salts of Baryta; by H. 
WAackeNnroper, (Chem. Gaz., July, 1847.)—Mix intimately 240 grms. 
of finely ground sulphate of ‘baryta, with 60 grms. rosin and 20 grmns. 
powdered charcoal. Heat to redness from half. to three quarters ’of an 
hour. Salts of baryta are prepared by precipitating the solution of 
nate of soda. 
id pure, crude muriatic acid is added to the solu- 
tion of sulphuret to slight excess ; the precipitated sulphur, sulphate of 
baryta, &c., is filtered off, and the solution eyaporated nearly to dry- 
ness. The impurities remain in the mother-liquid ; adhering chlorid of 
iron is removed by a faint red heat. 
Barytic water is prepared as usual by‘oxyd of copper. If this metal 
is found in the liquid after boiling, a small quantity of recently pr 
itated hydrated oxyd. of silver, or its carbonate, will on digestion 1 Te- 
move the copper and hypo- sulpburous acid. * 
The originality of this process, is in the use of rosin and pow odie 
charcoal instead of meal, and also in’a less degree of heat than is 
usually recommended. About — the «sulphate is go are 
The remainder can be used over again 
9. On the Fusion >of Rocks; by A. " DEnEsss, (Jour. dé” Pharm. et 
de Chem., Jan., 1848.)—The author has observed that the i igneous rocks 
on fusion undergo a diminution in ser 25 when they cool-into a vitri- 
ed mags, which is the greater in amount as thé rocks contain more 
silica and alkali, and less when more rods rats or alumina are pi rt. 
a a rule, the older rocks, as granite, &c., decrease most in 
e order is néarly that of their age down to the most modern 
shes which undergo but little change. This is of course a 
the order of their fusibility. 
uthor suggests _ the- crystallization of these rocks has des 
Crakaba, the radius of the earth, as a diminution of volume is the inevi- 
: table ~~ of Sialliaaticn, whether. — fusion or ee pr oe 
10. On anew Process for one diferent ‘Metals sae Bra 
ay, 
e used, employ a solution in water, composed of 500 parts of carbo- 
of potash, 20 parts of chlorid | gi bolaars 40 seated ag of 
¢, and 250 parts of nitrate of amm 
: order to obtain bronze, a salt of ere is substituted. for the sulphate 
neans of these solutions, wrought or cast iron, nec), Jend, 
‘ing ‘and the alloys of those metals, either with each other or with 
metal. The operation is performed at the ordisilian temperature 
article to be coated is put in communication with the negative on Fi of 
i, battery, the positive decomposing pole —— ate of — or® 
ronz 
