VOLATILE OIL OF GAULTHERIA PROCUMBENS. 217 
Oil of Gaultheria and Oxygen. — When oil of gaultheria 
is heated with an excess of potassa, the same reaction occurs 
as when saliculous acid is treated in the same way; a gaseous 
matter (hydrogen) is evolved, and the whole becomes a crys- 
talline mass on cooling, without a trace of the oil being per- 
ceptible. By dissolving this mass in water, and adding an 
excess of diluted hydrochloric acid, a white precipitate re- 
sults, which consists of tufts of crystals resembling benzoic 
acid. By washing with cold, and dissolving in boiling water, 
the solution, on cooling, yields beautiful silky four-sided 
prisms, with obliquely truncated summits. 
This substance possesses the properties of an acid; it is 
slightly soluble in cold water, to which it communicates an 
acid reaction, and much more soluble in boiling water, alcohol 
and ether. It fuses at 250° Fahr., and when further heated 
sublimes unchanged, condensing in long, very brilliant, four- 
sided needles, more regular than those obtained from water. 
The vapor of this acid excites coughing when inhaled; its 
taste is sweetish, like that of acetate of lead, and it irritates 
the fauces on swallowing. It decomposes the alkaline carbo- 
nates with effervescence, and forms with the salts of iron a 
fine purple solution. Nitric acid, sp. gr. 1,40, when cold, 
does not effect it; but if heat be applied, red fumes are evolved, 
and a yellow crystalline matter produced. Fuming nitric acid 
acts on this acid when cold. 
When this acid is saturated with potassa, a white salt is ob- 
tained in feathery crystals, which is soluble in water, alcohol 
and ether. It is precipitated by the soluble salts of lead and 
tin; but those of baryta, zinc, copper, magnesia and iron, do 
not. The salt of soda is similar to that of potassa. 
The ammoniacal salt crystallizes in needles. When heated 
to 260° Fahr., it fuses and sublimes in brilliant scales, having; 
an iridescent reflection. Too much heat partially decom- 
poses the salt, leaving a carbonaceous residue. It is soluble 
in water, and potassa added to its solution separates am- 
monia. 
When protosulphate of iron is added to a solution of either 
