Page:On the characters, properties, and uses of Eucalyptus globulus and other species of Eucalyptus.djvu/14

 constituents. It exudes abundantly during the summer months through punctures or wounds made in the leaves and young bark. As it exudes it hardens, and drops from the leaves on to the ground in pieces sometimes as large as an almond.

We may here refer to the fact that the flowers of species of Eucalyptus yield a large quantity of honey, and are therefore greatly affected by bees. It is said that Gould "has taken as much as a teaspoonful of honey from the mouth of a bird shot by him whilst it was feeding."

Another very important produce of the Eucalypti is the essential oil, which may be obtained in large quantities by aqueous distillation from the leaves. This oil is stored up in the pellucid glands already referred to as contained in the leaves, and readily observed when these are held up to the light by the semitransparent appearance they then exhibit. These oils are prepared on a very large scale by Mr. Bosisto, of Melbourne, and now form an important article of commerce with this country and elsewhere. Mr. Bosisto alone produces about 1000 lbs. of Eucalyptus oils per month. These oils generally have a somewhat camphoraceous smell; but the odour differs in the various species, and the oil obtained from E. citriodora has a pleasant citron-like odour.

Some of these oils have been employed, as Eucalyptus oleosa, as a solvent for resins in the preparation of varnishes; but they are of far more value for diluting the more delicate essential oils used in perfumery. They have been especially recommended for this and other purposes in this country by Mr. Rimmel; and specimens of soaps and other substances thus scented have been kindly sent by him for illustrations at the present lecture. The oils of E. amygdalina, E. globulus, and E. citriodora are thus more especially employed.

The oil chiefly consists of a substance called by its discoverer, M. Cloez (who made some interesting researches on the essential oil of E. globulus), eucalyptol, a liquid body, in chemical characters resembling camphor.

Most of these Eucalyptus oils are of a yellowish colour, although some have a bluish tint; by redistillation the oil may be obtained nearly colourless, as in the specimen now exhibited from Messrs. Savory and Moore, of Bond Street.

From the quantity of oil contained in the leaves, they yield, when burned, a very large proportion of gas; and it is said that one of the towns in the gold-regions was for a long time lighted by gas extracted from this source.