15 
PROCEEDINGS OF THE SOCIETY. 
Meeting, June 21, 1922 
PAGE 
339 
Authors of Papers printed in the Transactions are entitled to 25 copies of their 
communications gratis. Extra copies can be had at moderate charges on application 
to the Secretarj 7 . 
TRADE DIRECTORY and INDEX TO ADVERTISERS. 
Page 
Atha, J. W. & Co., 8 Southampton Row, London, W.C.l ... ... ... 10 
Bausch & Lomb Optical Co., Ltd., 37 Hatton Garden, London, E.C.l ... 4 
Beck, B. & J., Ltd., 68 Cornhill, London, E.C.3 ... ... ... Cover iv 
Browning, John, London, W.C.2 ... ... ... ... ... ... 12 
Cambridge & Paul Instrument Co., Ltd., Cambridge, and 45 Grosvenor 
Place, London, S.W.l ... ... ... ... ... ... Cover ii 
Clarkson’s, 338 High Holborn, London, W.C.l ... ... ... ... 13 
Dale & Hollins, 11 & 29 Sicilian Avenue, London, W.C.l ... ... ... 8 
Dolland’s, 35 Ludgate Hill, London, E.C.4 ... ... ... ... Cover ii 
Dulau & Co., Ltd., 34 Margaret Street, London, W.l... ... ... ... 10 
Flatters & Garnett, Ltd., 309 Oxford Road, Manchester ... ... ... 4 
Foyle, W. & G., Ltd., 121 Charing Cross Road, London, W.C.2 ... ... 4 
Gurr, George T., 35 Perrymead Street, Fulham, London, S.W. 6 ... ... 10 
Hawksley & Sons, 83 Wigmore Street, London, W.l... ... ... ... 2 
Heffer, W., & Sons, Ltd., 4 Petty Cury, Cambridge ... ... ... ... 2 
Kodak, Ltd., Kingsway, London, W.C.2 ... ... ... ... ... 6 
Leitz Microscopes ... ... ... ... ... ... ... ... ... 8 
Lewis, H. K., & Co., Ltd., 136 Gower Street, London, W.C.l ... Cover ii 
Ogilvy & Co., 18 Bloomsbury Square, London, W.C.l ... ... ... 8 
Rheinberg’s Eye-piece and Stage Micrometers, etc. ... ... ... ... 4 
Rudolph & Beesley, 65 Margaret Street, Oxford Circus, London, W.l ... 12 
Spencer Lens Co., Buffalo, New York, U.S.A., and 83 Wigmore Street, 
London, W.l ... ... ... ... ... ... ... ... ... 2 
Stevens’s Auction Rooms, Ltd., 38 King Street, London, W.C.2 ... ... 13 
Wallace Heaton, Ltd., 119 New Bond Street, London, W.l... ... ... 6 
Watson, W., & Sons, Ltd., 313 High Holborn, London, W.C.2 ... ... 16 
Wheldon & Wesley, Ltd., 38 Great Queen Street, London, W.C.2 ... ... 8 
Wratten Specialities for Microscopy ... ... ... ... ... ... 6 
Zeiss Microscopes ... ... ... ... ... ... ... ... ... 10 
FOR SALE 
SELECTED DIATOM SLIDES of Highest Class. Named Species, 
Circles, Groups and Types. Mounted in pure Styrex. Wm. A. Firth, 
348 Ravenhill Road, Belfast. 
