* * * * * LONDON: CHARLES GRIFFIN & CO., LIMITED, EXETER STREET, STRAND. * * * * * GRIFFIN’S NAUTICAL SERIES. Second Edition, Revised. With Numerous Illustrations. Price 3s. 6d. Practical Mechanics: Applied to the Requirements of the Sailor. BY THOS. MACKENZIE, _Master Mariner, F.R.A.S._ General Contents.--Resolution and Composition of Forces--Work done by Machines and Living Agents--The Mechanical Powers: The Lever; Derricks as Bent Levers--The Wheel and Axle: Windlass; Ship’s Capstan; Crab Winch--Tackles: the “Old Man”--The Inclined Plane; the Screw--The Centre of Gravity of a Ship and Cargo--Relative Strength of Rope: Steel Wire, Manilla, Hemp, Coir--Derricks and Shears-- Calculation of the Cross-breaking Strain of Fir Spar--Centre of Effort of Sails--Hydrostatics: the Diving-bell; Stability of Floating Bodies; the Ship’s Pump, &c. “This EXCELLENT BOOK ... contains a LARGE AMOUNT of information.” --_Nature._ “Well WORTH the money ... will be found EXCEEDINGLY HELPFUL.” --_Shipping World._ “No Ships’ Officers’ Bookcase will henceforth be complete without Captain Mackenzie’s ‘Practical Mechanics.’ Notwithstanding my many years’ experience at sea, it has told me _how much more there is to acquire.”_--(Letter to the Publishers from a Master Mariner). “I must express my thanks to you for the labour and care you have taken in ‘Practical Mechanics.’ ... It Is A LIFE’S EXPERIENCE.... What an amount we frequently see wasted by rigging purchases without reason and accidents to spars, &c, &c.! ‘Practical Mechanics’ WOULD SAVE ALL THIS.”--(Letter to the Author from another Master Mariner). * * * * * WORKS BY RICHARD C. BUCK, of the Thames Nautical Training College, H.M.S. ‘Worcester.’ A Manual of Trigonometry: _With Diagrams, Examples, and Exercises. Price 3s. 6d._ Third Edition, Revised and Corrected. =⁂= Mr. Buck’s Text-Book has been SPECIALLY PREPARED with a view to the New Examinations of the Board of Trade, in which Trigonometry is an obligatory subject. “This EMINENTLY PRACTICAL and RELIABLE VOLUME.”--_Schoolmaster_. a Manual of Algebra. _Designed to meet the Requirements of Sailors and others._ Second Edition, Revised. Price 3s. 6d.