Miscellanies. 203 
The last acid represents an atom each of butyric and caproic acids, 
minus an atom of oxygen ; it is not constant, being found only occasion- 
ally. These acids are obtained by saponifying butter with potash in a 
convenient apparatus, then adding sulphuric acid and distilling, when the 
volatile acids will come over with the water; they are saturated with ba- 
rytic water, concentrated, and afterwards reduced to dryness in a retort; 
the residue is boiled with five or six parts of water, which dissolves a por 
tion ; the solution separated and allowed to cool, deposits crystals of ca- 
proate of baryta in the form of silky needles, that are to be separated 
from the mother water, which when evaporated by the heat of the sun, 
deposits the butyrate of baryta; both of these salts are purified by recrys- 
tallization. When vaccinic acid is present, it generally takes the place of 
butyric and caproic acids, and is deposited from the concentrated solution 
in combination with baryta in groups of small crystals that effloresce. 
The baryta salts of difficult solution that are left in the retort are dissolv- 
ed in as much boiling water as will just hold them in solution, filtered 
while hot; on cooling, the caprate of baryta is deposited in minute 
scales of a fatty lustre—upon concentrating to about three fourths, an 
additional quantity of this salt is obtained. The mother water, exposed 
to the heat of the sun, furnishes the capryllate of baryta; these are also 
purified by recrystallization. All the acids can now be obtained by heat- 
ing their barytic salts in a retort with dilute sulphuric acid. 
Atomic Weights of Copper, Mercury, and Sulphur, by ErpMAnn and 
Marcuanp, (Chem. Gazette, Sept. 1844, p. 399.)—That of the copper 
was estimated by decomposing a known quantity of binoxide of copper 
in a current of hydrogen gas, and weighing the residue of the metallic 
copper ; it was done with all the minute precautions necessary ; the result 
was 31°7, (hyd. 1.) The atomic weight of mercury was estimated by 
decomposing a known quantity of pure oxide of mercury, by copper turn- 
ings and charcoal, collecting the metallic mercury formed, and estimating 
its weight; the result was 100. That of sulphur was ascertained by de- 
composing pure vermilion with copper filings and heat, and ascertaining 
the amount of mercury; the atomic weight is 16. 
Deoridation of the Ferridcyanide of Potassium, (red prussiate of pot- 
ash, Fe? Cy?-+3KCy,) and of the Salts of the Peroride of Tron, by 
Prof. Scndnsein, (Jour. fiir Prakt. Chem. Vol. 30, p. 129.)—The re- 
sults of the author’s experiments upon the red prussiate of potash are 
certainly improperly styled deoxidation, as there is no oxygen in the com- 
pound in question, nor is it necessary to presuppose the agency of oxygen 
in all cases in bringing about the reactions to be mentioned; decyaniding 
would perhaps be a more correct term, for it appears that certain sub- 
stances convert the ferrid into the ferrocyanide of potassium—a cyanide 
containing less cyanogen. Any of the metals, including silver and even 
