52 SECTIONAL ADDRESSES. 



containing addenda does not involve any change of valency. It is, how- 

 ever, significant that [Ag, 3 etu] CI is a water-soluble salt which remains 

 colourless even after prolonged exposure to light. 



A contribution to the chemistry of bivalent silver has been made by 

 co-ordinating its ion with a-a'-dipyridyl (dipy), and the following coloured 

 salts have been isolated [Ag, 2 dipyJSaOg (chocolate brown), [Ag, 2 dipy] 

 (HSO^)^ (dark brown plates) and [Ag, 3 dipy] (ClOJ., crystallising in well 

 defined, lustrous, black, acicular prisms. 



Stabilisation of the aurous condition. — Co-ordination of gold salts with 

 ethylenethiocarbamide has the same effect as with copper compounds. 

 The fundamental univalency of the metallic ion becomes stabilised so 

 that the following complex aurous salts have been identified : [Au, 2 etu]., 

 SO,, 2H.,0, [Au, 2 etu] NO,, [Au, 2 etu] CI, H,0 and [Au, 2 etu] Br, H.,0^ 

 These compounds are colourless and dissolve in water to practically neutral 

 solutions (Pji value about 6"2). Conductivity experiments indicate that 

 in dilute aqueous solutions these complex salts are highly ionised so that 

 the complex radical [Au, 2 etu]' plays the part of a compound alkali ion. 

 The bromide of this series was mentioned last year by Prof. W. E. Dixon 

 (he. cit.) as being a compound which had the effect of delaying death 

 when administered to animals infected with bovine tuberculosis. 



Chemical Engineering. 



The mainstay of the foregoing investigations are the well-equipped 

 workshops manned by five skilled artisans who are engaged on the produc- 

 tion and maintenance of the appliances and plant required in the various 

 research programmes. Appliances for high-pressure chemistry are a 

 speciality of the laboratory workshops, and such plant includes bombs 

 and pre-heaters for flow-through experiments with gaseous reagents, and 

 autoclaves of various types for reactions with gases, liquids and solids. 

 The researches on tar products call for automatic extractors, filter plant 

 and stills operating under either ordinary or diminished pressures. 



The State Laboratory and the Scientific Public. 



The twofold primary aim of any State research laboratory should be 

 the collection and dispersal of scientific knowledge and information. For 

 the former function of collection and discovery of new knowledge the 

 exploring parties foreseen by Prof. Vernon Harcourt should supply an i 

 adequate means providing that each group proceeds under enlightened 

 and inspired leadership. But for the complementary function of dispersal] 

 of information a chemical laboratory must depend largely on such well- 

 established media of publication as the journals of the leading chemical! 

 societies. The greater part of the published research of the Teddingtonf 

 laboratory has appeared in the Journals of the Chemical Society and of] 

 the Society of Chemical Industry, although a certain proportion has been] 

 published in the Proceedings of the Royal Society, Journal of the Institutej 

 of Metals, and Proceedings of the Institution of Chemical Engineers. 

 Grateful recognition should be recorded for the generous aid afforded by 

 all these learned societies, and special thanks are due to the first two 

 mentioned. It is my personal opinion that this mode of dispersing 

 chemical knowledge should have priority over its publication in 



