ADVKKTISKMENTS Stanley . Manufacturers of . .^___ LdONTDON^ SLIDE RULES . of All Descriptions . Please send for J 105 Catalogue (Post Free) Iff. F. Stanley & Co. LIMITED Great Turnstile, Holborn, London, w.c. Showrooms - 286 HIGH HOLBORN, W.C. SLIDE RULES & CALCULATORS CALCULATING SLIDE RULES, mahogany body, with inlaid white celluloid back and iront. Engine-divided scales, glass cursor in aluminium frame. In case with in. structions, 10" 10/6 ; 15" 28/- ; 20" 55/- ; 24" 63/-. IMPROVED PERRY SLIDE RULE, with Log. -Log. Scales, 18/-. MAGNIFYING CURSORS for the above Slide Rules. PROELL'S POCKET CALCULATOR, post free, 3/1. PROELL'S STEAM CALCULATOR (graphic), British, Metric and Kilowatt-hours per ton of steam, 5/-. Curve Paper Log. Paper Semi = Log. Paper DRAWING INSTRUMENTS For Price List apply to — JOHN J. GRIFFIN & SONS, Ltd,, KINGSWAY, LONDON, W.C. Makers of Scientific Apparatus
