88 
OBSERVATIONS ON MONARDIN. 
the rhombohedron or some form derivable from it. By cool- 
ing a portion of fused monardin until crystallization is partially 
effected, and then pouring off the superstratum, it is obtained 
in very regular crystals. The sp. grav. of the amorphous va- 
riety is 1.03. When in crystals the enclosed air renders them 
lighter than water. It is neutral to test paper. 
Monardin is soluble in a solution of caustic potassa, and 
by saturating the alkali with acetic acid it separates in the 
form of an oil, which, by standing, assumes the same crystal- 
line form, and possesses the same odour as before subjection to 
the alkaline menstruum. 
When crystals of monardin are placed in a solution of am- 
monia they gradually assume the form of oily globules, with- 
out dissolving in the ammoniacal liquid, and remain at the bot- 
tom. Whilst undergoing this change they have the appear- 
ance of fusing. The globules of monardin, after treating 
with ammonia, solidify when subjected to a temperature as 
low as 18° Fahr. By exposure to the air these globules gra- 
dually assume a purple colour, and when heated with caustic 
potassa no ammonia is evolved. 
When crystallized monardin is introduced into a jar of am- 
moniacal gas over mercury, the ammonia is rapidly absorbed, 
and the crystals are liquified. When suffered to remain until 
saturated, they absorb nearly one hundred times their bulk of 
the gas, and are increased in bulk more than fifty per cent. 
When the liquified monardin is exposed to the air, it gradually 
assumes the crystalline form apparently unchanged. Oil of 
horsemint also absorbs ammonia, but not by any means in so 
great a quantity, or with any marked phenomena. 
Monardin dissolves in cold concentrated sulphuric acid, to 
which it communicates a red tinge. The solution may be di- 
luted and saturated with an alkali without the separation of 
any oily or crystalline matter, evidently proving that the mo- 
nardin is changed. 
Concentrated hydrochloric acid appears to have little, if 
