“It is certainly an extremely rare thing for a reviewer to be called upon to notice a volume measuring but 2½ in. by 1¾ in., yet these dimensions faithfully represent the size of the handy little book before us. The volume--which contains 118 printed pages, besides a few blank pages for memoranda--is, in fact, a true pocket-book, adapted for being carried in the waistcoat pocket, and containing a far greater amount and variety of information than most people would imagine could be compressed into so small a space.... The little volume has been compiled with considerable care and judgment, and we can cordially recommend it to our readers as a useful little pocket companion.”--_Engineering._ _Analysis, Technical Valuation, Purification and Use of Coal Gas._ By the Rev. W. R. BOWDITCH, M.A. _With wood engravings_, 8vo, cloth, 12_s._ 6_d._ Condensation of Gas--Purification of Gas--Light--Measuring--Place of Testing Gas--Test Candles--The Standard for Measuring Gas-light--Test Burners--Testing Gas for Sulphur--Testing Gas for Ammonia--Condensation by Bromine--Gravimetric Method of taking Specific Gravity of Gas--Carburetting or Naphthalizing Gas--Acetylene--Explosions of Gas--Gnawing of Gaspipes by Rats--Pressure as related to Public Lighting, etc. _A Practical Treatise on Natural and Artificial Concrete, its Varieties and Constructive Adaptations._ By HENRY REID, Author of the ‘Science and Art of the Manufacture of Portland Cement.’ New Edition, _with 59 woodcuts and 5 plates_, 8vo, cloth, 15_s._ _Hydrodynamics_: Treatise relative to the Testing of Water-Wheels and Machinery, with various other matters pertaining to Hydrodynamics. By JAMES EMERSON. _With numerous illustrations_, 360 pp. Third edition, crown 8vo, cloth, 4_s._ 6_d._ _The Gas Analyst’s Manual._ By F. W. HARTLEY, Assoc. Inst. C.E., etc. _With numerous illustrations._ Crown 8vo, cloth, 6_s._ _Gas Measurement and Gas Meter Testing._ By F. W. HARTLEY. Fourth edition, revised and extended. _Illustrated_, crown 8vo, cloth, 4_s._ _The French-Polishers Manual._ By a French-Polisher; containing Timber Staining, Washing, Matching, Improving, Painting, Imitations, Directions for Staining, Sizing, Embodying, Smoothing, Spirit Varnishing, French-Polishing, Directions for Repolishing. Third edition, royal 32mo, sewed, 6_d._ _Hops, their Cultivation, Commerce, and Uses in various Countries._ By P. L. SIMMONDS, Crown 8vo, cloth, 4_s._ 6_d._ _A Practical Treatise on the Manufacture and Distribution of Coal Gas._ By WILLIAM RICHARDS. Demy 4to, with _numerous wood engravings and 29 plates_, cloth, 28_s._ SYNOPSIS OF CONTENTS: