9^ ORIGINAL COMMUNICATIONS. 
cinchonia is a protoxide, quinia a deutoxide, and aricina a tri- 
toxide of this base. 
An equally beautiful instance of this simplicity of arrange- 
ment is furnished in the composition of camphor. The 
essential oil of lemons is a hydro-carbon, containing H"^ C*. 
It is isomeric with the essential oil of turpentine, which con- 
sists of C^°. This hydro-carbon is an electro-positive 
radical, and has received the name of camphene; for its pro- 
toxide is the well known substance camphor, its 5-oxide is 
camphoric acid, and its chloride is the artificial camphor, 
produced by the action of chlorohydric acid upon oil of 
turpentine. 
Another compound radical of great interest, which has not 
yet been insulated, is benzule. It consists of C^^^H* 0^ Its 
hyduret is the essential oil of bitter almonds, its oxide is an- 
hydrous benzoic acid, and it forms a chloride, a cyanide, and 
a sulphuret. 
The essential oil of the spirea ulmaria, which is probably 
the same oil that is obtained from the gaultheria procumbens, 
is a hydracid, having a very complex radical. This radical 
is called spirule and consists of C^^H^O^ It forms com- 
pounds with chlorine, iodine, bromine, oxygen, and the metals, 
in a manner perfectly analogous to cyanogen. The oil of 
cinnamon is also a feeble hydracid, the base of which forms 
another acid with oxygen. 
The ammoniacal salts of many of the organic acids, when 
decomposed by heat, appear to be resolved into a new com- 
pound, which is such that the addition of an atom of water 
re-converts it into a salt of ammonia. 
The oxalate and the benzoate of ammonia, furnish examples 
of this change, and the substances into which they are changed 
are called oxamide and benzamide. Urea is an example of 
this class of substances. Its composition is such, that the 
addition of an atom of water will convert it into carbonate of 
ammonia ; while, on the other hand, the abstraction of an 
atom of water converts it into anhydrous cyanate of am- 
monia. 
