Chemistry and Physics. 257 
soon as the heat reaches the neck of the still, the fire is to be 
slackened, when the distillation proceeds rapidly and continues without 
further heat. : 
The chloroform is to be separated as usual, but the liquid which floats 
over it is immediately employed in the following manner. Without re- 
moving any thing from the still, 10 quarts of water are to be added ; 
when the whole has cooled to about 100° Fahr., add 6 or 8 pounds 
ef quick lime and 22 pounds of chlorid of lime ix well, and pour 
in the liquid ryt from the preceding distillation, together with an- 
other quart of alco The operation is to be con nducted as before, 
and if the still is ings enough, a third or even fourth operation may 
be made with a tage. 
Thus, 3825 ue: valantial gave the Astsliatitlin , 950 grms. chloroform. 
2d "640 3) 
3d 6c 700 73 
4th * 730 Fe 
The authors from an estimate conclude that this substance can be made 
for 14 francs the kilogramme, or $1°25 per pound. As advantages of 
their process, they point out the previous heating of the water, and the 
absence of all swelling up, owing to the use of lime and the water bath. 
“ On the Cepsiatianee Sapte’ Oxyd of Zinc; by M. J. Nicxzs, 
. de Chim de #@hy Sig oe 1848.)—The mineral known as cu- 
peo ree of zinc, contains hydrate of zinc and copper, and 
erystallizes in the right te (trimetric) sysiem. Anxious to as- 
certain whether the pure artificial hydrate of zine belonged to the same 
system, it was prepared by the process of Runge. Iron and zinc are 
These proved to belong to the same system with the mineral above 
named, 
In the course of preparation several curious particulars were noted, 
The sheet zinc of commerce was readily ‘attacked, while cast zinc re- 
fused to dissolve. The difference is attributed to the crystalline texture 
existing in the cast zinc, but entirely destroyed by the process of roll- 
in ng—the amorphous condition being always more favorable to solution 
than the crystalline. On the other hand, iron in the shape of turnings 
was found more favorable to the action than any form of wrought iron 
—the crystalline structure here rendering the metal more negative. In 
all cases the intensity of the reaction is measured by the disengagement 
of hydrogen. Ammonia affords the best crystals. 
Lead was ‘substituted for iron with success; also copper, when it was 
noticed that though there was free exposure to the air, no coloration 
took place, provided both metals were someloiels immersed, Solution 
of oxyd of zinc in ammonia is however decomposed by copper—the 
liquid becoming blue, while crystals of the hydrated oxyd are formed. 
The blue solution in its turn is decomposed by metallic zine with a pre- 
cipitation of aren These reactions are cited by the author as de- 
serving attentio 4 G. C. S. 
