Oil of Lemon (Oleum Limonis, Oleum Citri)
is one of the most important essential oils for the perfumer as well as the manufacturer of liqueurs, confectioner, etc. The oil is pale yellow, and of a very strong refreshing odor which it loses rapidly in contact with the air, when it acquires a disagreeable odor of turpentine and gradually resinifies. This change is particularly marked under the influence of light. Its spec. grav. is 0·850 at 20° C. (68° F.). It is soluble in an equal volume of strong alcohol or glacial acetic acid. The hand-pressed oil has a much finer aroma than that obtained by distillation.