_Heliotropin_, which possesses the characteristic odour of heliotrope,
is prepared artificially from safrol. It crystallises in small prisms
melting at 86 deg. C.

_Hyacinth._--Most of the articles sold under this name are secret blends
of the different makers. Styrolene has an odour very much resembling
hyacinth, and probably forms the basis of most of these preparations,
together with terpineol, and other artificial bodies. The properties of
the oil vary considerably for different makes.

_Ionone_, a ketone first prepared by Tiemann, and having when diluted a
pronounced violet odour. It is prepared by treating a mixture of citral
and acetone with barium hydrate, and distilling in vacuo. Two isomeric
ketones, [alpha]-ionone and [beta]-ionone, are produced, the article
of commerce being usually a mixture of both. The two ketones have the
following properties:--

Alpha-ionone.--Specific gravity at 15 deg. C., 0.9338; refractive index at
16.5 C., 1.50048 (Chuit); optically it is inactive.

Beta-ionone.--Specific gravity at 15 deg. C., 0.9488; refractive index at
16.8 deg. C., 1.52070 (Chuit); optically it is inactive also.

The product is usually sold in 10 or 20 per cent. alcoholic solution
ready for use.

_Jasmine._--This is one of the few cases in which the artificial oil is
probably superior to that obtained from the natural flowers, possibly
due to the extreme delicacy of the odour, and its consequent slight
decomposition during preparation from the flowers. The chemical
composition of the floral perfume has been very exhaustively studied,
and the artificial article now on the market may be described as a
triumph of synthetical chemistry. Among its constituents are benzyl
acetate, linalyl acetate, benzyl alcohol, indol, methyl anthranilate,
and a ketone jasmone.

_Linalol_, the alcohol forming the greater part of linaloe and bois de
rose oils, and found also in lavender, neroli, petitgrain, bergamot, and
many other oils. The article has the specific gravity at 15 deg. C.,
0.870-0.876; optical rotation, -12 deg. to -14 deg.; refractive index at 20 deg. C.,
1.463-1.464; and when estimated by acetylation, yields about 70 per
cent. of alcohols.

_Linalyl acetate_, or _artificial bergamot oil_, is the ester formed
when linalol is treated with acetic anhydride. It possesses a
bergamot-like odour, but it is doubtful whether its value is
commensurate with its greatly increased price over that of ordinary
bergamo