﻿April iStli, 1905.] Proceedings. xxxvii 



Secretaries: Francis Jones, M.Sc, F.R.S.E., F.C.S. ; 



Charles H. Lees, D.Sc. 

 Treasurer: Arthur McDougall, B.Sc. 

 Librarian: W. E. HoYLE, M.A., D.Sc, F.R.S.E. 

 Other Members of the Council: C. E. Stromeyer, M.Inst.C.E.; 



W. Thomson, F.R.S.E., F.C.S. ; Thomas Thorp, 



F.R.A.S. ; Charles Bailey, M.Sc, F.L.S. ; R. L. 



Taylor, F.C.S., F.I.C. ; Charles Oldham. 



Ordinary Meeting, April 18th, 1905, 



Professor W. Boyd Dawkins, D.Sc, F. R.S., President, 

 in the Chair. 



The thanks of the members were voted to the donors of the 

 books upon the table. 



Mr. F. J. Faraday, F.L.S. , presented to the Society's 

 Library a copy of "The Life of Thomas Fuller, D.D., with 

 notices of his books, his kinsmen, and his friends." By J. E. 

 Bailey. 1874. 



Mr. H. Stansfield, B.Sc, exhibited a new method of 

 producing coloured diffusion bands. One surface of a piece of 

 plate glass, rendered diffusive by spoiling the polish or coating 

 it with a diffusing film of resin or butter, was fixed so as to be 

 nearly in contact with the reflecting surface of a polished silver 

 mirror, the surfaces being separated at the corners by a single 

 thickness of stamp-edging. Greater dispersion of the colours is 

 obtained in this way than by breathing on the glass surface of a 

 silvered mirror, as the air film can be made much thinner than 

 the mirror glass. A diffusion mirror whose glass surface had 

 roughly parallel grease markings, imitated the action of a diffrac- 

 tion grating. One of Mr. Thorp's transparent diffraction . 

 gratings, backed up with a silver surface in the same way, showed 

 a variety of diffusion effects superposed on the diffraction spectra, 



