$94 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS (d) Figure 16 Comparison chromatograms of oils of spike from four different regions of Spain- (c) Guadalajara, (d) Soria. distillation methods are very similar in all districts. Fig. 16 shows that differences can exist among the early peaks of oils from various parts of the country. The group which precedes cineole varies in size, but the relative heights of its peaks cannot be used--like those of Group A--D above-- to differentiate dearly between them. However, there appears to exist some tendency towards greater consistency of pattern within dis- tricts, which suggests that gas-liquid chromatography may be more critical in respect of source than is normally demanded by classifications for perfumery trade purposes.

GAS-LIQUID CHROMATOGRAPHY AND THE PERFUMER 395 The effect of working conditions is hardly as great in practice as might be anticipated, since factors such as still design, and time of distillation, tend to become standardized for economic reasons. Too short an extraction period decreases the relative proportions of less volatile constituents, but otherwise few significant changes are observable. In fact, chromatograms obtained directly from lavender flowers are surprisingly like those of the steam-distilled oils. Fig. 17 shows results in two cases. In each experi- ment, a flower was kept for 5 minutes by a by-pass preheater at 130 ø C, after which the vaporized oil was flushed out and chromatographed at 70 ø C. (a) Chromatograms from individual lavender flowerst(a) ordinary, (b) Maille•e (see also Figs. 11 and 15).