78 
MISCELLANY. 
reon. Digest these together until the color becomes a yellowish green, 
then distil off the greater part of the spirit. Add water to the residue, 
when a green substance of a soft consistence will be separated, and one 
part of this is to be mixed with four parts of yellow wax, and eight 
parts of olive oil, to form the cerate. — Ibid, from Buchner's Reper* 
torium. 
Application of the Residue of Iron Pyrites, employed in the Manufac- 
ture of Oil of Vitriol. By M. Berrael. — The manufacture of oil of 
vitriol from iron pyrites, in the countries in which this substance is 
abundant, being advantageous in a commercial point of view, it is im- 
portant to discover a profitable application for what has hitherto been 
considered as the refuse of the process. 
In a manufactory in Belgium, where sulphuric acid, and also soda is 
made, the residue left after burning the pyrites, and which contains sul- 
phate of iron, is mixed with sea salt in excess, and heat applied in a 
proper apparatus ; hydrochloric acid, is thus obtained, and sulphate of 
soda, which is purified by solution and crystallization. The remaining 
peroxide of iron is separated, by washing, into two parts : that which is 
in the finest powder, being dried and mixed with grease, is used as an 
antiattrition for machinery, and answers the purpose well; the coarser 
powder is made into small pellets, dried and treated as iron ore. 
In manufactories where soda is not made in connection with sulphuric 
acid, instead of extracting the sulphate of iron from the burnt pyrites, 
it is found more advantageous to distil the residue (the sulphate of iron 
being already dry) so as to obtain the fuming acid. 
It is easy to arrange the apparatus in such a manner, that the sul- 
phurous acid resulting from the decomposition of a part of the sulphate 
during the distillation, may be conducted into the leaden chambers. 
Nothing is lost in this process, the residue being obtained in the state 
of colcothar. — Ibid, from Compies Rendus. 
Tests for Phosphorous Acid. By M. Wohler.— Some phosphoric 
acid, when examined to ascertain whether it contained arsenic, gave by 
heat, with sulphurous acid, a yellow precipitate of sulphuretof arsenic. 
This phosphoric acid contained, as was shown on a more attentive ex- 
amination, arsenious and phosphorous acids. 
It was seen, indeed, that phosphorous acid possesses the property of 
being converted into phosphoric acid by the action of sulphurous acid, 
especially when aided by heat. This transformation is caused by the 
decomposition of the water; and there is a formation of sulphuretted 
