400 SECTIONAL TRANSACTIONS.— B. 



Prof. N. V. SiDGWicK, C.B.E., F.R.S. (12.20). 

 General Discussion. 



Afternoon. 

 Visit to the works of the Cambridge Instrument Company. 



Prof. C. S. Gibson, O.B.E., F.R.S. ; assisted by Dr. F. G. Mann, Mr. 

 H. V. Thompson and Dr. F. H. Braiisi .—Demonstration in Section B 

 lecture room on the production of gold films by chemical methods (5.15). 



During 1856, Faraday was occupied in determining the experimental 

 conditions for the production of thin metallic, chiefly gold, films with a view 

 to the investigation of their optical properties. This work had important 

 consequences in other directions and Faraday refers to ' this long and as 

 yet nearly fruitless set of experiments on gold ' probably because he was not 

 successful in producing gold films to his own satisfaction. It is interesting, 

 however, that Faraday appears to foreshadow the modern method of pro- 

 ducing films of gold and other metals by the ' sputtering ' process. 



The demonstration is concerned with some methods of the production 

 of gold films and their application in the arts. The application of gold 

 films to surfaces of glass and porcelain has long been known and the pro- 

 duction of gold mirrors — having magical properties and being the criteria 

 of excellence — whether of glass to which beaten gold was applied mechani- 

 cally or of polished alloy was known to the early Chinese, Egyptians, Greeks 

 and Romans. A recipe for the production of a golden mirror is given by 

 Geber. The application of gold films to ceramics is described and demon- 

 strated as far as possible by Mr. H. V. Thompson, M.A., with the collabora- 

 tion of Mr. Bernard Moore and Messrs. Colclough China, Ltd., of Stoke- 

 on-Trent. Dr. F. G. Mann shows the production of gold films on glass 

 by the action of heat on the trialkylphosphineaurous halides which he has 

 recently described. Prof. C. S. Gibson, F.R.S., and Dr. F. H. Brain 

 demonstrate the production of gold films by the decomposition of organic 

 gold compounds at the ordinary temperature and indicate their application 

 in the arts especially as mirrors and for decorative purposes by a number 

 of specimens. 



Friday, August 19. 



Symposium on Modern methods of chemical analysis {Exhibition) (lo.o). 



Dr. J. J. Fox, C.B., O.B.E. — Introduction. 



The requirements of analytical chemistry are now so extensive, that the 

 older methods have had to be revised and extended in many directions. 

 Particularly the development of methods of micro- and semi-micro-methods 

 has attracted workers all over the world. It is not too much to state that 

 these methods, and their accuracy, have rendered possible investigations 

 which could not have been carried out without them. An important 

 advance in analytical methods arises from the extending utilisation of 

 physical processes. These have resulted in advance in two directions, 

 namely, accuracy and speed of analysis. For example, the use of spectro- • 

 graphic methods renders it possible to examine alloys of various kinds with 

 speed and sufficient accuracy for many industrial processes. Further, the 



