A group of papers by Dr. M. W. Travcrs, 

 F.R.S., Dr. W. E. S. Turner, Mr. Robert Mond, and 

 Mr. F. Twyman, dealt with Optical Glass. 



GLASS FOR OPTICAL PURPOSES. 

 By Morris W. Travers, D.Sc, F.R.S. 



I have beeii associated witli the glass industry since the outbreak 

 of war, but the manufacture of optical glass in this country has 

 been a matter of secrecy, and only officials have been admitted to 

 the works, so that persons like myself can know only of what has 

 been done indirectly and by rumour, British scientific literature 

 contains one or two papers, indirectly connected with the subject, 

 and the public and semi-scientific press contains only references to 

 claims to discoveries of " German secrets " by British scientists — 

 and denials that there were any secrets to discover. I hope that 

 the claims are of a more substantial character than those put forward 

 in connection with scientific glassware. 



During the past autumn I made a tour of America, where I 

 visited several of the new optical glass plants, to which I was freely 

 admitted, and met many of the men who had been engaged in 

 the development of the industry. During the early years of the 

 war the manufacture of optical glass had been carried on in a 

 rather desultory fashion, but in April, 1917, American industry 

 was suddenly called upon lb meet an enormous demand for optical 

 glass. It might have been thought that America would have made 

 use of the information gathered in this country, but an American 

 scientist who took a leading part in developing the industry told 

 me that this was not the case, for " we understood that your Govern- 

 ment had a lot of information on the subject of optical glass, but 

 we could get nothing out of them at all." 



America was, however, in a very advantageous position from 

 which to attack the problem. In the first place there were ample 

 funds for research, administered by a thoroughly scientific body^ 

 the National Research Council, and not by a Government Depart- 

 ment, scientific only in name. In the second place there already 

 existed the organisation of the Geophysical Laboratory of the 

 Carnegie Institution. Of the work of this institution the Report 

 of the Director for the^ year 1918 speaks as follows: — " Suffice it 

 to say that with a group of 20 scientifically trained men, all trained 

 in handling silicate solutions at temperatures required for the making 

 of glass, and familiar with the control of most of the important 

 factors in the problem, it proved practicable to make rapid pro- 

 gress, and in June following, after two months of concentrated 

 effort, the gross production of glass by a leading manufacturing 

 firm had increased from 15,000 to 28,000 pounds per month, and 

 in quality had improved to such an extent that rejections by Govern- 

 ment inspectors became comparatively rare." The results are really 

 expressed in the last sixteen words of the quotation. 



