_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. * * * * * _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 large plates_, cloth, 28_s._ SYNOPSIS OF CONTENTS: Introduction--History of Gas Lighting--Chemistry of Gas Manufacture, by Lewis Thompson, Esq., M.R.C.S.--Coal, with Analyses, by J. Paterson, Lewis Thompson, and G. R. Hislop, Esqrs.--Retorts, Iron and Clay--Retort Setting--Hydraulic Main--Condensers--Exhausters--Washers and Scrubbers--Purifiers--Purification--History of Gas Holder--Tanks, Brick and Stone, Composite, Concrete, Cast-iron, Compound Annular Wrought-iron--Specifications--Gas Holders--Station Meter--Governor--Distribution--Mains--Gas Mathematics, or Formulæ for the Distribution of Gas, by Lewis Thompson, Esq.--Services--Consumers’ Meters--Regulators--Burners--Fittings--Photometer--Carburization of Gas--Air Gas and Water Gas--Composition of Coal Gas, by Lewis Thompson, Esq.--Analyses of Gas--Influence of Atmospheric Pressure and Temperature on Gas--Residual Products--Appendix--Description of Retort Settings, Buildings, etc., etc. * * * * * _Practical Geometry and Engineering Drawing_; a Course of Descriptive Geometry adapted to the Requirements of the Engineering Draughtsman, including the determination of cast shadows and Isometric Projection, each chapter being followed by numerous examples; to which are added rules for Shading Shade-lining, etc., together with practical instructions as to the Lining, Colouring, Printing, and general treatment of Engineering Drawings, with a chapter on drawing Instruments. By GEORGE S. CLARKE, Lieut. R.E., Instructor in Mechanical Drawing, Royal Indian Engineering College, Cooper’s Hill. 20 _plates_, 4to, cloth, 15_s._ * * * * * _The Elements of Graphic Statics._ By Professor KARL VON OTT, translated from the German by G. S. CLARKE, Lieut. R.E., Instructor in Mechanical Drawing, Royal Indian Engineering College, Cooper’s Hill. Crown 8vo, cloth, 5_s._ _See page 3._ * * * * *