November ii, 1920] 



NATURE 



347 



abrasives. Much work has already been done 

 both from the purely scientific point of view and 

 on the production of abrasive powders. Materials 

 made in the laboratory are being tested in work- 

 shops, and it is hoped soon to publish reports on 

 the whole investigation and on the practical 

 results. 



Again, in response to a need expressed by the 

 industry a solder was prepared in the association's 

 laboratories, capable of being used for all the 

 ordinary metals, including aluminium, and of with- 

 standing a temperature of approximately 350° C, 

 so that it could be used when the later heating of 

 joints made by it was necessary — e.g. in enamel- 

 ling. This also has been manufactured on a large 

 scale, and industrial firms are engaged on ex- 

 tended tests of it. The reports to hand are very 

 promising. Another solder, fusing at a low tem- 

 perature, for special use with aluminium, has also 

 been made on the laboratory scale, as the outcome 

 of the previous research, and is now being tested 

 by certain firms. 



The association has also been able to give im- 

 mediate assistance in the matter of securing suit- 

 able and trustworthy liquids for level bubbles, and 

 is now engaged on problems connected with stand- 

 ardising the glass for the bubbles and with 

 methods of preparing the inside surface. In this 

 connection it has been considered important that 

 purely scientific research on the fundamental 

 physical problems connected with this investigation 

 should be prosecuted so that not only may the 

 practice in manufacturing level bubbles be im- 

 proved, but also the reasons underlying it may be 

 fully elucidated. This is being done for the asso- 

 ciation, extramurally, in one of the London tech- 

 nical colleges. 



An interesting investigation, apparently dealing 

 only with a small detail brought to the attention 

 of the association, led to a considerable amount 

 of research work on the cause of the tarnishintr 

 which had been found with certain tissue papers 

 used for wrapping up polished glass. A repiort on 

 the whole research has been issued to members, 

 and so far as the practical issue is concerned the 

 position is apparently quite clear as to the pro- 

 perties which the paper must have and the method 

 of testing whether it has them. Here, again, the 

 research has given rise to problems which are of 

 great interest in connection with physical and 

 chemical questions about colloids, and would be 

 suitable for further investigation on academic 

 lines. It is under consideration what arrange- 

 ments can be made for this work to be done else- 

 where in some university or technical collie. 



Another research of immediate practical import 

 ance to the optical industry is the research on 

 cements for prisms and lenses. A rcoorf on this 

 subject has been issued to members, and in the 

 important matter of obtaining cements which have 

 no tendency to change either in the direction of 

 crystallisation or in the gradual deposition of 

 insoluble matter, and do not tend to break 

 away from the glass surface, very considerable 

 progress has been made. This investigation on 

 NO. 266.^. VCL. IO6I 



cements has led to a large amount of relevant 

 work in the matter of insulators, a subject of im- 

 portance to the electrical members of the associa- 

 tion, and is an example of the advantage of the 

 wider outlook which is obtained in an association 

 such as this where the needs of one of its depart- 

 ments are co-ordinated with those of another. 

 There are, of course, many scientific problems 

 raised here which might well prompt pure science 

 research — e.g. into the causes and conditions of 

 crystallisation or of other instability in resinous 

 and similar substances. 



Questions on the purity of chemical compounds 

 and on the relation of purity to stability are raised 

 by the research being undertaken by the associa- 

 tion to study the durability of different tvpes and 

 meltings of optical glass under a variety of con- 

 ditions. Similarly, another research of the asso- 

 ciation into the question of the production of a 

 glass of truly neutral tint raises fundamental ques- 

 tions of the theory of colour in glass. 



It is impossible in a short article to do more 

 than take almost at random a few examples of 

 the researches being undertaken by the associa- 

 tion, but enough has been said, oerhaps, to show 

 that, even in those researches being prosecuted for 

 immediate practical ends, fresh problems in pure 

 science are raised, or wider vistas opened out, 

 which may well be suggestive and stimulating to 

 the workers in the laboratories of purely scientific 

 institutions. 



The programme of research of the association is, 

 naturally, rather the private affair of the associa- 

 tion, but it may 'be said that it ranges from prob- 

 lems in pure science involving the fundamentals 

 of optical, electrical, or chemical theory to tech- 

 nological investigations on the methods and 

 materials of manufacture, including, for example, 

 such a practical problem as the best lacquer for 

 making an instrument look well finished. 



It may be well to point out that, besides the 

 specific researches included in the programme of 

 research, the association in its character as the 

 scientific centre of the industry is called upon from 

 time to time to assist the industry by contributing 

 from a scientific point of view suggestions and 

 criticisms to the appropriate Government and 

 other quarters on such matters as the supplies of 

 raw materials and the manufacture in this country 

 of products essential to the development of the 

 British scientific instrument industry. Much work 

 in this direction has already been done. More- 

 over, users of scientific instruments have already 

 brought to the notice of the association, and. as 

 the association becomes better known, will doubt- 

 less tend increasingly to bring to its notice, their 

 specific needs. In this way the association will 

 perform a useful scientific liaison office between 

 the users and the manufacturers. Already, by 

 means of conferences and otherwise, the associa- 

 tion has enabled the manufacturing members to 

 become better a<-quainfed with the scientific needs 

 of the users, and the users to apprecintr th^ 

 limitations imposed on the manufacturci^ li\ 

 design, material, or other conditions. 



