3 o SCIENCE PROGRESS 



contain lipoids. The lower members of the homologous series 

 of alcohols are comparatively odourless since they are sparingly 

 soluble in fats, whereas the higher alcohols, such as cetyl alcohol, 

 being only sparingly soluble in water, likewise only smell faintly. 

 Butyl and amyl alcohols, on the other hand, being soluble both 

 in water and fats, smell strongly, and the same applies to aromatic 

 hydrocarbons, nitro-compounds, amines, bromoanilines, naph- 

 thylamines, etc. The alteration of solubility in water and fats 

 also explains the reason why acetylation increases the smell of 

 ethyl alcohol and destroys that of aniline. The Relation between 

 Odour and Constitution is discussed by Prins (/. Soc. Chem. Ind. 

 191 7, 36, 942). According to Magewski the odour of a substance 

 was due to a so-called osmophoric group, but according to the 

 present author all groups should be regarded as osmophoric, 

 but in different degrees. The similarity in odour of all benzene 

 derivatives is due to the predominant osmophoric properties 

 of the benezene nucleus. Aliphatic hydrocarbons have a much 

 weaker osmophoric influence, hence the great difference in 

 smell between octylalcohol, octoic aldehyde, and octoic acid. 

 Homologous substances such as octaldehyde, nonaldehyde, and 

 decaldehyde and their corresponding alcohols have similar 

 odours. Double bonds in the neighbourhood of an alcohol, 

 aldehyde or carboxyl group have a marked influence on odour, 

 as for example decaldehyde and undecenaldehyde, citronellal 

 and citral, a-ionone and /3-ionone. The influence of formic acid 

 predominates over that of the alcohol in formic esters, and is 

 least in the formates of strongly osmophoric alcohols such as 

 borneol and menthol. 



GEOLOGY. By G. W. Tyrrell, A.R.C.Sc, F.G.S., University, Glasgow. 



Stratigraphical and Regional Geology. — From the Summary of 

 Progress (Geol. Survey of Great Britain, Summary of Progress 

 for 1 91 6, 191 7, pp. 56) we learn that the work of the Survey is 

 now restricted almost entirely to the examination of economic 

 materials, especially refractories, coal, and iron ore, in con' 

 nection with war requirements. 



The Highland Border rocks of the Aberfoyle district (Perth- 

 shire), in which Prof. T. J. Jehu recently made an important 

 discovery of fossils, are fully described in a paper by Prof. 

 Jehu and Dr. R. Campbell (Trans. Roy. Soc. Edinburgh, 1917, 



