questioned whether it would stand being called by the name of
dimethyl-2-6-octadiene-2-6-ol-8. Geraniol by oxidation goes into the
aldehyde, citral, which occurs in lemons, oranges and verbena flowers.
Another compound of this group, linalool, is found in lavender, bergamot
and many flowers.

Geraniol, as you would see if you drew up its structural formula in the
way I described in the last chapter, contains a chain of six carbon
atoms, that is, the same number as make a benzene ring. Now if we shake
up geraniol and other compounds of this group (the diolefines) with
diluted sulfuric acid the carbon chain hooks up to form a benzene ring,
but with the other carbon atoms stretched across it; rather too
complicated to depict here. These "bridged rings" of the formula
C_{5}H_{8}, or some multiple of that, constitute the important group of
the terpenes which occur in turpentine and such wild and woodsy things
as sage, lavender, caraway, pine needles and eucalyptus. Going further
in this direction we are led into the realm of the heavy oriental odors,
patchouli, sandalwood, cedar, cubebs, ginger and camphor. Camphor can
now be made directly from turpentine so we may be independent of Formosa
and Borneo.

When we have a six carbon ring without double linkings (cyclo-aliphatic)
or with one or two such, we get soft and delicate perfumes like the
violet (ionone and irone). But when these pass into the benzene ring
with its three double linkages the odor becomes more powerful and so
characteristic that the name "aromatic compound" has been extended to
the entire class of benzene derivatives, although many of them are
odorless. The essential oils of jasmine, orange blossoms, musk,
heliotrope, tuberose, ylang ylang, etc., consist mostly of this class
and can be made from the common source of aromatic compounds, coal tar.