240 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Consistency Melting Sample Composition (Mean of 10) Point, øC. 2907A 2908A 2909A 2910A 2911A 2912A 2913A 2914A Straight white Petroleum Jelly 170 40.9 2907A + 1% paraffin wax 163 41.8 2907A + 5% paraffin wax 158 42.7 2907A + 10% paraffin wax 136 43.6 Straight Yellow Petroleum Jelly 172 40.5 Straight Yellow Petroleum Jelly, different source 158 41.6 Straight White Petroleum Jelly, different source from 2907A 162 42.3 Straight White Petroleum Jelly, different source from 2907A and different grade from 2913A 164 43.4 It will be apparent to you from reading these results that the firmer the jelly, the lower its consistency conversely, a soft jelly will show a high con- sistency and, although the melting point between samples may be only small, the difference in consistency can be large. Whether you require a petroleum jelly with a low or high consistency depends upon your particu- lar problem but to those of you in the audience who have not before used the penetrometer I would say that this instrument is of use in the classifi- cation of petroleum jellies, providing it is appreciated that consistency is not necessarily related to quality. ASSESSING THE QUALITY OF AN ESSENTIAL OIL* By G. W. FERGUSON, B.Sc., Pu.D., F.R.I.C. Parry & Ferguson, London, S.E.I, England "QUALITY" IS a somewhat vague term, especially when applied to essential oils, on account of its wide scope. Its general meaning may be taken as suitability for all purposes for which the product in question may be used. In so far as essential oils are concerned, assessment of quality involves several factors which differ in importance according to the principal use to which the oil is to be put, These factors are in the nature of specific requirements and are quite independent of the intrinsic "genuineness" of the oil, which for the mo- ment may be assumed to conform with recognised trade standards in its * Presented at the April 9, 1954, Meeting, London, England.

240 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Consistency Melting Sample Composition (Mean of 10) Point, øC. 2907A 2908A 2909A 2910A 2911A 2912A 2913A 2914A Straight white Petroleum Jelly 170 40.9 2907A + 1% paraffin wax 163 41.8 2907A + 5% paraffin wax 158 42.7 2907A + 10% paraffin wax 136 43.6 Straight Yellow Petroleum Jelly 172 40.5 Straight Yellow Petroleum Jelly, different source 158 41.6 Straight White Petroleum Jelly, different source from 2907A 162 42.3 Straight White Petroleum Jelly, different source from 2907A and different grade from 2913A 164 43.4 It will be apparent to you from reading these results that the firmer the jelly, the lower its consistency conversely, a soft jelly will show a high con- sistency and, although the melting point between samples may be only small, the difference in consistency can be large. Whether you require a petroleum jelly with a low or high consistency depends upon your particu- lar problem but to those of you in the audience who have not before used the penetrometer I would say that this instrument is of use in the classifi- cation of petroleum jellies, providing it is appreciated that consistency is not necessarily related to quality. ASSESSING THE QUALITY OF AN ESSENTIAL OIL* By G. W. FERGUSON, B.Sc., Pu.D., F.R.I.C. Parry & Ferguson, London, S.E.I, England "QUALITY" IS a somewhat vague term, especially when applied to essential oils, on account of its wide scope. Its general meaning may be taken as suitability for all purposes for which the product in question may be used. In so far as essential oils are concerned, assessment of quality involves several factors which differ in importance according to the principal use to which the oil is to be put, These factors are in the nature of specific requirements and are quite independent of the intrinsic "genuineness" of the oil, which for the mo- ment may be assumed to conform with recognised trade standards in its * Presented at the April 9, 1954, Meeting, London, England.