The new Department was a tribute to Walker's vision. The laboratories could accommodate 400 undergraduates and one of the main features, for which he was criticised at the time, was the extensive provision made for research workers; there were over 30 research rooms, the smaller rooms accommodating two workers and the larger three or four. Hitherto there had been little incentive for students to stay on after graduation but now that space was available and the research Degree of Ph.D. had been instituted, the number of postgraduates progressively increased.

The writer wishes to acknowledge her indebtedness to Dr H G Rule for his helpful suggestions and advice during the course of this work.

The relative changes in the rotatory power of a compound produced by the introduction of a number of different substituents have been comparatively little investigated until recent years. Much of the work carried out in this direction has been limited to the study of homologous series, as in the case of the menthyl esters of aliphatic acids examined by Tschugaeff, the corresponding amyl esters by Guye and Ghavanne (Comptes rendus 1895, 120, 152) and menthyl esters of carvoxime by Rupe and Wolfaleben (Annalen, 1912, 395, 136).

A great deal of systematic work of this nature has been accomplished by Pickard and Kenyon in connection with optically active secondary carbinols and their esters and ethers.

Two generalisations have emerged from these researches and others of similar type. In the first instance, it is now accepted that the introduction of a methyl group in place of hydrogen often produces a marked change in the rotatory power of the parent compound, but that the subsequent lengthening of the chain by the introduction of succeeding methylene groups produces less and less change in the rotation, until in many cases a constant value is finally attained.

In the second place, it is frequently observed that the curve representing the change undergone by the molecular rotation in a homologous series as the number of carbon atoms increases is broken by an inflexion corresponding to a maximum or minimum at or about the fifth, tenth and fifteenth carbon atoms in the chain, counting from the asymmetric atom. These effects have been explained by Frankland on the basis of Baeyer's strain theory as being due to the influence of the end of the chain as it returns upon itself in space.

In recent years a considerable amount of attention has been directed towards the influence of substituents on the physical and chemical behaviour of a parent compound. These researches have had to do with such diverse properties as benzene substitution, velocity of reaction, optical activity, dielectric constants, and physical state. As a result, it has been made abundantly clear that in nearly all these cases the main influence at work falls into one of two categories. The first and most commonly observed influence is that usually described as the 'general effect' of the substituent, which is regarded as being due to a general shift of the valency electrons away from an electropositive group ... and towards an electro-negative one ...

Her work was characterised by method and efficiency. Her accurate knowledge and skilful manipulation combined with a flair for teaching made her an ideal instructress. ... With both staff and students Dr Numbers was persona grata.

In memory of my Auntie Anne, Annie Hutton Numbers, MA, BSc, PhD, 1897-1988, one of the 'spinster generation'. Without her unfailing guidance and encouragement in my early life I would have achieved very little.