10 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS less oil, and secondly the result from careful fractionating which yields the rhodinol of commerce. Without attempting any comment upon the unsettled question of the chemistry of the rhodinols, it may be noted in the pelargonium and in other flower oils that geraniol is associated with the laevorotatory form of citronellol. The proportional balance in the R6union oil may be regarded as 50: 50 whereas the oils of African origin average about 80: 20 those of French distillation showing approximately 70: 30 and the Spanish oils 60: 40, noting in passing that it is usually the French oil which is distilled over rose petals to yield the beautiful Geranium sur Rose. It would therefore appear that this equipoise in the Bourbon oil provides an ideal foundation for simulations of Bulgarian otto of rose, while increasing the content of/-citronellol emphasises the lighter and sweeter nuances of rose centifolia, Damascene, the moss and the tea roses. THE "GRASS" OILS It is also instructive briefly to review several of the economical sources from which the geranium oils of commerce are obtained and to note the variations in the odour-patterns of these oils which are distilled, not from leaves, but from flowering grasses. In order of importance these are Pal- marosa and the Java, Ceylon and Formosa citronella oils. Distillation in India of Cymbopogon Martini var. (Motia-.•ass) yields Palmarosa or "Turkish" geranium oil (containing from 75 to 90 per cent of free geraniol) which has a fine, soft, mellow rose-geranium odour singularly free from unwanted alien off-notes, which is not unduly surprising when it is noted that the addendum is brief, consisting chiefly of small quantities of the acetic and caproic geranyl esters, methyl heptenone and dipentene. Another example from a similar species known locally as Sofia-grass yields ginger-grass oil, but in this instance the geraniol in a much smaller yield is associated with an entirely different framework formulated around the presence of carvone, dihydrocuminol, phellandrene apd dipentene, from which emerges a strong and somewhat unpleasant herbal back-note which is difficult to eliminate from the geraniol even by repeated fractionation. Java citronella, distilled from C. nardus, is interesting for several reasons, firstly because it introduces us to a very important source of a fine quality geraniol, and secondly, whereas this alcohol is found in liaison with/-citronellol in Bourbon geranium, in the Java oil its companion is the aidehyde d- citrondial to the extent of about 35 per cent of each. This aidehyde, when reduced, provides the d-citronellol of commerce, but it must be observed on comparison that there is a considerable odour difference between the relatively coarse rose-type scent of the dextro-version and the refined, suave and sweeter rosy fragrance of the laevo-modification.

THE GERANIUM FAMILY IN PERFUMERY 11 The odour-framework, which with the terpenes constitutes the remaining 30 per cent in the make-up of the Java oil, according to the literature, is seen to comprise some thirty items, but just how some of these contribute towards the composite aroma it is difficult to assess, and although the presence of citronellyl and geranyl acetates is noted, yet some inter-esterification is probable from the occurrence of butyl and amyl alcohols which donate certain fruity notes. These are complemented by green nuances, following the incidence of hexanol, hexenol and methyl heptenone, while traces are found of cadinol, methyl eugenol and citral. All of these, be it noted, are very powerful osmophores, and must there- fore blend to effect a profound modifying action upon the basic odours of the two main constituents. Citronella Ceylon. A brief glance at the build-up of Ceylon citronella (ex Andropogon nardus) reveals another storehouse of ancillary aromatics. This oil is important commerciall 5 as an economical source of a second- grade geraniol and d-citronellal, the approximate balance of these con- stituents being as 30:10, but the incidental components only amount, however, to about a dozen items. These comprise, in addition to the acetic esters, methyl eugenol and methyl heptenone, common to both oils, but the incidence of small amounts of such dominant osmophores as borneol, cam- phene and thujyl alcohol is sufficient to repress the more delicate fragrance, due to traces of a nerol-linalol complex and farnesol hence in comparison with the odour of the Java oil, that from Ceylon is crude and heavy, being somewhat unbalanced by the background of herbaceous elements. The Formosan oil inclines closely towards the Java type, and is interesting for the formulation of economical, yet powerfnl bases for industrial perfumes, as well as being an important commercial source of the aromatic isolates and their derivatives: geraniol, citronellal, citronellol, the corresponding esters, hydroxycitronellal and synthetic menthol. INTERESTING FRAGRANCE-PATTERNS One of the most interesting natural associations of geraniol, and incident- ally a pattern which with variations is typical of quite a number of fragrant Australasian flora, is to be found in the foliage of Boronia Muelleri (N.O. Rutaceae), in which the rosy geraniol note is complemented by an aromatic- balsamic nuance of the fennel-myrrh type, backed by pinene and refreshed with geranyl acetate. From this ensemble a very pleasing and intriguing bouquet emerges. In the antipodes there are qui•e a number of these fragrant Boronias with distinctive and well-defined odours, B. citriodora, for example, yields an oil containing upwards of 80 per cent of/-citronellol, another source of which is Eucalyptus citriodora while Verbena (Aloysis or Lippia) citriodora,