Classical and Educational Works. 29 ON THE CONVERSION OF HEAT INTO WORK. A Practical Handbook on Heat-Engines. By William Anderson, M. Inst. C.E. With 64 Illustrations. Pp. viii.-254. Cr. 8vo. 6^. SEWAGE TREATMENT, PURIFICATION AND UTILIZATION ; A Practical Manual for the Use of Corporations, Local Boards, Officers of Health, Inspectors of Nuisances, Chemists, Manufacturers, Riparian Owners, Engi- neers and Ratepayers. By J. W. Slater, F.E. S., Editor of "Journal of Science. " Crown 8vo. cloth, price bs. THE TELEPHONE. By W. H. Preece, F.R.S., and J. Maier, Ph.D. With numerous illustrations. Cr. 8vo. 1 2 J. dd. MANURES, OR THE PHILOSOPHY OF MANURING. By Dr. A. B. Grifaths, F.R.S.Ed., F.C.S., Principal and Lecturer on Chemistry in the School of Science, Lincoln, &c., &c. Cr. 8vo. 7j. bd. HYDRAULIC MOTORS : TURBINES AND PRESSURE MOTORS. By George R. Bodmer, Assoc. M.Inst. C.E. is. ALTERNATING CURRENTS OF ELEC- TRICITY. By Thomas H. Blakesley, M.A., M.Inst.C.E. 4f. iid. In preparation. GALVANIC BATTERIES. By Professor George Forbes, M.A. INDUCTION COILS. By Professor A. J. Fleming, M.A., D.Sc. THE DYNAMO. By Guy C. Fricker. Others to follow. NIPHER (F. E.) THEORY OF MAGNETIC MEASUREMENTS, WITH AN APPENDIX ON THE METHOD OF LEAST SQUARES. One volume. Crown 8vo. cloth, 5J-. PLANTE (G.) THE STORAGE OF ELECTRI- CAL ENERGY, and Researches in the Effects created by Cur- rents combining Quantity with High Tension. Translated from the French by Paul Bedford Elwell. With Portrait, and 89 Illustrations. 8vo. pp. vii.-268, cloth, lis.