202 ODOROGRAPHIA. 
which passed over, on being set aside for some time, deposited 
erystals which had all the appearance and properties of benzoic 
acid. Stenhouse adds that the quantity of these crystals at his 
disposal was so small that they could not be subjected to analysis. 
He proved them not to be cimnamic acid, for on treating them 
with a hot solution of hypochlorite of lime they did not give the 
very characteristic reaction of cinnamic acid, viz., “the produc- 
tion of that singular chlorinated oil which is always produced 
when cinnamic acid is treated in this way.” They were proved 
to be benzoic acid in the following way :—‘ When the last por- 
tions of the oil which had come over, together with the residue 
remaining in the retort, were digested with strong nitric acid, 
along with much oxalic acid, a small quantity of another kind of 
erystals were obtained, which in appearance and properties agreed. 
perfectly with nitrobenzoic acid. The first portions of the colour- 
less oil which distilled over were again rectified, when the boiling- 
point was by no means constant, though the greater portion of 
the oil came over at a temperature approaching the boiling-point 
of eugenol *. 
“The oil was treated with an excess of potash, and the hydro- 
carbon which did not combine with the alkali was drawn off by 
a pipette. It was next treated with fused potash, then with 
calcic chloride, and lastly rectified over potassium. In this way a 
colourless, highly refractive liquid was obtained, the greater 
portion of which distilled over between 160° and 165° C. Its 
sp. gr. was 0°862 and its odour closely resembled that of cymene, 
the result of its analysis agreeing exactly with the formula C,H, 
(a body which is contained in several essential oils, or which can 
at all events be withdrawn from them). 
“The portion of the oil which dissolved in potash lye was 
heated for a considerable time, with agitation, in order to drive off 
the last portions of the hydrocarbon which might be adhering to 
it. It was next saturated with sulphuric acid and the liberated 
eugenol still further purified. It agreed perfectly in its cha- 
racters with those ascribed to eugenol by Bonaster, Ettling, and 
* In Stenhouse’s original paper he calls this “ eugenic acid,’—a term which 
was formerly applied to eugenol because this liquid forms crystallizable com- 
pounds with the alkaline bases. (Although Stenhouse’s researches may now 
appear antique, they are yet of interest to instance his method of procedure.) 
