Chemistry and Physics. 
When hyposulphite of soda is added to a solution of alum as nearly 
neutral as possible, no precipitate is produced, but on heating to 60° C, or 
70° C., sulphurous acid is disengaged, and alumina mixed with free sul- 
phur precipitated, the reaction being expressed by the equation 
Al2zOs, 380s +3(Na 0, S202) = Al2Os+-38+-3802+4-3(Na O, SOs). 
? To render the precipitation complete, the solution containing the alumina 
: must be very dilute, and must be boiled to expel sulphurous acid. r 
| the separation of iron and alumina the author recommends the following 
: rocess. The sulphuric or chlorbydric solution of alumina and iron is to 
saturated with carbonate of soda until very nearly neutral, and water 
added till the liquid contains not more than 1 decigramme of alumina in 
50 cubic centimeters. To this solution, which must be cold, a slight ex- 
cess of hyposulphite of soda is to be added, and the whole allowed to 
stand until the liquid becomes completely decolorized. The liquid is then 
to be boiled until sulphurous acid is no longer disengaged. The precipi- 
; tate of alumina and sulphur is to be filtered and washed with boiling 
: water. The alumina is not gelatinous, but very compact, and may be 
: wash ith great ease. The ignition must, of course, take place in a 
porcelain crucible; the alumina obtained is perfectly white. The filtrate 
from the alumina contains all the iron. It is to be evaporated and treated 
Comptes Rendus, xlvi, 987. ; 
ore.—It would doubtless be much simpler to pass chlorine gas 
through the solution containing the iron after the separation of the alumina. 
irectly converted into sulphuric 
* 
‘ The hyposulphurous acid would be th 
: acid, and the iron peroxydized.—w. «.] 
| 5. On the | Calcitum.— 
tained by the action of iodhydric acid upon white marble, evaporatin, the 
solution and fusing the salt out of contact of air; as thus repared it re- 
b i d proved on analyses to be j 2 : 
on, iene wk respect to the properties of calcium, as well as a 
of their results in reducing barium and strontium by a similar pro- 
zinc-ethyl is heated with sodium, zinc is precipi 
ND Vor. XXVI, No. 78.—NOV., 1858. 
SECO: 
