B.— CHEMISTRY. 49 



In addition to the preparation of antimonials directly applicable to 

 therapeutic tests, our knowledge of the organic chemistry of antimony has 

 been extended among aliphatic derivatives by the production of antimony 

 analogues of the cacodyl group and in the aromatic series by the synthesis 

 of cyclic antimonials analogous to the alkyl- and aryl-carbazoles. 



Water Pollution Research. 



This research originated from a joint request made to the Department 

 of Scientific and Industrial Research by the Ministry of Health and the 

 Ministry of Agriculture and Fisheries. 



During the past two years, experiments have been in progress under 

 the auspices of the Water Pollution Research Board on the base-exchange 

 method of water softening. One of the objects of this work has been to 

 determine the most satisfactory way of carrying out the process, such 

 points having been examined as the effect of varying the rate of flow of 

 water through the bed of base-exchange material and the quantity, 

 concentration and time of contact of the salt solution used in regenerating 

 this material. There are two tjipes of base-exchange material in actual 

 industrial use, treated minerals and synthetic products prepared by 

 interaction of solutions of sodium aluminate and sodium silicate. It 

 appears from the result of the Teddington experiments that with treated 

 minerals the exchange of bases is confined to the outer surface of the 

 particles whereas with the synthetic materials diffusion to the inner 

 surfaces or into the mass of the gel is an important factor. This study of 

 the base-exchange process has also been extended to the case of waters 

 rich in magnesium. 



Disintegration of the base-exchange materials and contamination of 

 the softened waters by silica and alumina have been investigated. At the 

 rate of flow employed normally in water softening, the silica content of 

 the water is not increased seriously and is certainly not greater than that 

 often encountered in untreated waters. 



In addition to this practical work a report summarising existing 

 knowledge of the base-exchange or zeolite process for water softening has 

 been compiled and published. 



General Research. 



Investigation of complex aromatic hydrocarhons.^ln 1926 the Dyestuffs 

 Industry Development Committee of the Board of Trade suggested that 

 further fundamental research was desirable on the following coal tar 

 products : acenaphthene, carbazole, fluorene, perylene and phenanthrene. 

 Two of these suggestions were adopted and, with the assistance of two 

 chemists, the Director, who is also a member of this Statutory Committee, 

 undertook a study of acenaphthene and perylene, the work being continued 

 until 1928. During this period considerable progress was made with the 

 former hydrocarbon, the nitration of which was studied under anhydrous 

 and hydrous conditions. For nitrations, in the absence of water, 

 diacetylorthonitric acid and benzoyl nitrate were employed, the latter 

 being a reagent discovered originally in 1906 by Prof. Francis of this 

 university. Several new nitro derivatives were identified, and 2-amino- 

 1930 g 



