Pocket size, in neat case, with instructions and examples. Post Free, 7s. 6d. net. C. N. PICKWORTH, Withington, Manchester ┌─────────────────────────────────────────────────────────────────────┐ │ W. P. THOMPSON, G. C. DYMOND, │ │ F.C.S., M.I.Mech.E., F.I.C.P.A. M.I.Mech.E., F.I.C.P.A. │ │ │ │ W. P. Thompson & Co., │ │ 12 CHURCH STREET, LIVERPOOL, │ │ CHARTERED PATENT AGENTS. │ │ │ │ H. E. POTTS, J. V. ARMSTRONG, │ │ M.Sc., Hon. Chem., F.I.C.P.A. M.Text.I., F.I.C.P.A. │ │ │ │ W. H. BEESTON, R.P.A. │ └─────────────────────────────────────────────────────────────────────┘ ------------------------------------------------------------------------ BRITISH SLIDE RULES for all ARTS and INDUSTRIES including [Illustration: [Slide Rule]] _LOG-O-LOG DR. YOKOTA’S SURVEYORS’ WIRELESS GUNNERY ELECTRICAL RULES, Etc._ SEND FOR LIST 55 MADE BY— JOHN DAVIS & SON (Derby), Ltd. ALL SAINTS’ WORKS, DERBY ------------------------------------------------------------------------ K & E Slide Rules are constantly growing in popularity, and they can now be obtained from the leading houses in our line throughout the United Kingdom. [Illustration: [Slide Rule]] We manufacture a complete line of ENGINE-DIVIDED SLIDE RULES, and call special attention to our Patent Adjustment, ensuring smooth working of the Slide; also to our new “Frameless” Indicator, which hides no figures on the Rule. [Illustration: [Thacher’s Calculating Instrument]] THACHER’S CALCULATING INSTRUMENT, for solving problems in multiplication, division, or combinations of the two; has upwards of 33,000 divisions. Results can be obtained to the fourth and usually to the fifth place of figures with a surprising degree of accuracy. We also make ALL METAL, CIRCULAR, STADIA, CHEMISTS’, ELECTRICAL, and OTHER SPECIAL SLIDE RULES _DESCRIPTIVE CIRCULARS ON REQUEST_