On a Theory Concerning the Sudden Loss of Magnetic Properties of Iron and Nickel.--By Mr. A. TOMLINSON, B.A.--A new theory, involving the probable rearrangement of the molecules or "magnetic atoms" of the metals in question. 10358 The Passive State of Iron and Nickel.--Note of this curious phenomenon. 10347 The Wimshurst Electric Machine.--Illustration of 13½ inch sparks produced by it.--1 illustration. 10352 The Application of Electricity to Lighting and Working.--By W. H. PREECE.--Lecture I. 10350 VII. ENTOMOLOGY.--Systematic Relations of Platypsyllus as determined by the Larva.--By Dr. C. V. RILEY.--An important contribution to entomological science, a paper read at the meeting of the National Academy of Science, April 20, 1888.--4 illustrations. 10356 VIII. HYGIENE.--Reducing Obesity--Note of general principles to be applied to diet and life. {Transcriber: Omitted by publisher.} 10352 The Care of the Eyes.--By Prof. DAVID WEBSTER.--A practical and scientific examination of how to preserve the eyesight and of the use and abuse of this important organ of sense. 10352 Sanitation in Massachusetts. 10352 IX. MECHANICAL ENGINEERING.--Hydraulic Tube Press.--An extraordinarily powerful press for striking up tubes from flat plates. 10345 The Distribution of Hydraulic Power in London.--A recent system introduced in London, with description of the plant and distribution pipes. 10344 The One Hundred and Twenty Ton Shears of the Port of Marseilles.-- An immense set of hoisting apparatus described and illustrated.-- 3 illustrations. 10343 X. PHOTOGRAPHY.--Colored Photography.--Mr. J. E. MAYALL'S recent advances in this phase of photography. 10349 XI. PHYSICS.--Scientific Apparatus at the Manchester Royal Jubilee Exhibition.--Notes of the most interesting electrical, photometrical, and communicating apparatus. 10348 The Spectra of Oxygen.--Interesting investigations of absorption spectra of oxygen. 10358 XII. SURGERY.--Papillomatous Tumor of the Bladder, demonstrated by Means of Lister's Electro-cystoscope.--By F. N. OTIS, M.D.-- An interesting instance of the use of an exploratory electric light.--2 illustrations. 10354