166 H. Rose on a new mode of preparing Aluminium, 
at three Prussian dollars per cwt. Samples of 40 lbs. had been 
handed to the soap-inanofacturers of this place: aud in faet by 
treating them with burnt lime, a soda-ley was prepared from it, 
which probably froma its very admixture on alumina proved 
very superior for the manufacture of certain s 
I recognised in this powder the mineral phe of the same 
purity as the crystals obtained through Mr. Krantz. It dissolved 
perfectly (in a platinum vessel) and “without leaving any wsoln- — 
ble matter in hydrochloric acid ; the solution evaporated with 
sulphuric acid to dryness, showed a deposit, which heated to the’ 
expulsion of the free sulphuric acid. proved perfectly soluble in 
water with the aid of some hydrochloric acid. In the solution, 
a considerable precipitate of alamina was obtained by ammonia. 
A filtered solntion thereof gave after evaporation and heating a 
deposit of sulphate of soda, which contained no potassium. Be- 
sides this, the powder showed the kuown reactions of fluorine in 
a very high degree, 
This powder is therefore cryolite of great purity. Still the 
coarse powder which | obtained at first, was not the original form 
in which it comes in commerce. The eryolite arrives here in 
Berlin iu large masses. For the purpose of preparing aluminium 
it must be reduced however toa very fine powder, 
n my experiments for the preparation of the metal which I 
made conjointly with Mr. Weber and with important aid from 
him, I have used, thus far, for the most part, small iron crucibles 
1? inches high, and 12 iuchas oe ih which I had cast ina 
foundery of “this lace. In these [I stratified the fine cryolite 
powder with thin layers of sodinm, seein the whole preity 
strongly, and covered it with a good cover of chlorid of potas- 
sim, and the crucible with a well fitting porcelain cover. Of all 
the fluxes, I found the chlorid of potassium the most sears 
geous; it has the least specific gravity, which in view of the 
ery. small density of the aluminium is of great consequence. 
ides it fuses with the flnorid of sodinm to a mass more fusi- 
ble than the latter alone, I usually employed equal proportions 
of chlorid of potassium and of eryolite, and for five parts of the 
latter [ took two parts of sodium. Ten grams of cryolite powder 
ee auswered the best for the crucible. 
[he ‘The whole was then exposed to a powerful red heat, by means 
ofa blowing apparatus, in which atmospheric air aud iluminating 
gas is foreed through pipes constructed after the principle of ~ 
wis pipe in the explosive gas-blowpipe apparatus. It appe 
to be the: best to continue the red heat during half an hour aul 
longer, keeping all the time the crucible carefully closed. 
Seawhiie the whole is well fused. After cooling, the contents 
of the crucible are best cleared by means of a feller. which ope- 
ration may be facilitated by gentle blows with on the 
