To ensure the correctness of these Tables of Logarithms, they were compared with Callett’s, Vega’s, Hutton’s, Briggs’, Gardiner’s, and Taylor’s Tables of Logarithms, and carefully read by nine different readers; and further, to remove any possibility of an error remaining, the stereotyped sheets were hung up in the Hall at Cambridge University, and a reward offered to anyone who could find an inaccuracy. So correct are these Tables, that since their first issue in 1827 no error has been discovered. * * * * * _The Steam Engine considered as a Heat Engine_: a Treatise on the Theory of the Steam Engine, illustrated by Diagrams, Tables, and Examples from Practice. By JAS. H. COTTERILL, M.A., Professor of Applied Mechanics in the Royal Naval College, 8vo, cloth, 12_s._ 6_d._ * * * * * _The Practice of Hand Turning in Wood, Ivory, Shell, etc._, with Instruction for Turning such Work in Metal as maybe required in the Practice of Turning in Wood, Ivory, etc., also an Appendix on Ornamental Turning. (A book for beginners). By FRANCIS CAMPIN. Second edition, _with wood engravings_, crown 8vo, cloth, 6_s._ CONTENTS: On Lathes--Turning Tools--Turning Wood--Drilling--Screw Cutting--Miscellaneous Apparatus and Processes--Turning Particular Forms--Staining--Polishing--Spinning Metals--Materials--Ornamental Turning, etc. * * * * * _Health and Comfort in House Building, or Ventilation with Warm Air by Self-Acting Suction Power_, with Review of the mode of Calculating the Draught in Hot-Air Flues, and with some actual Experiments. By J. DRYSDALE, M.D., and J. W. HAYWARD, M.D. Second edition, with Supplement, demy 8vo, _with plates,_ cloth, 7_s._ 6_d._ * * * * * _Treatise on Watchwork, Past and Present._ By the Rev. H. L. NELTHROPP, M.A., F.S.A. _Numerous illustrations_, crown 8vo, cloth, 6_s._ 6_d._ CONTENTS: Definitions of Words and Terms used in Watchwork--Tools--Time--Historical Summary--On Calculations of the Numbers for Wheels and Pinions; their Proportional Sizes, Trains, etc.--Of Dial Wheels, or Motion Work--Length of Time of Going without Winding up--The Verge--The Horizontal--The Duplex--The Lever--The Chronometer--Repeating Watches--Keyless Watches--The Pendulum, or Spiral Spring--Compensation--Jewelling of Pivot Holes--Clerkenwell--Fallacies of the Trade--Incapacity of Workmen--How to Choose and Use a Watch, etc. * * * * * _Now in Course of Publication._ To be completed in about 30 Monthly Parts, each Part containing 64 pp., with _numerous illustrations_, super-royal 8vo, price 2_s._; or in 5 Divisions, cloth, price 13_s._ 6_d._ each. DIVISIONS I., II, & III., NOW READY. SPONS’ ENCYCLOPÆDIA OF THE INDUSTRIAL ARTS, MANUFACTURES, AND COMMERCIAL PRODUCTS.