For the Week ending July 14, 1877.

I. ENGINEERING AND MECHANICS.—Wrought Iron Bridge Designs; by William O. Douglas. A method of construction whereby the safety of the structure is not dependent on any single member. 2 engravings.—Steel Wire Hawsers.

Health and Sewage of Towns; by Alfred Carpenter, M.D., C.S.S. A practical experience of the Dry system.

Carlisle Bridge, Dublin, 1 engraving—Extinction of Fires.—Important Dutch Enterprise.

Foot Bridge across the River Ness at Inverness; by C. R. Manners, Engineer. 13 illustrations.

Radiating Steam Hercules for the St. Heliers' Harbor Works, Jersey. 2 figures.—New Meat Trucks.—New Horseshoe.—Scott's Wheel-Cutting and Moulding Machine. 3 figures.

Compound Engine with Rope Driving Gear; by Benjamin Goodfellow, Engineer. 3 engravings.—Differential Screw Pipe Joint. 6 figures.

Pipes for Gas and Other Purposes (continued from Supplement No. 77). Main-laying continued, with 4 figures.—Fittings of Gas and Water Pipes; Includes the average "life" of pipes; an account of various soils, and amount of corrosion in each; Professor Barff's new iron-preserving process, and other processes in practical use for preserving iron pipe; proving pipe; the utility of various metals, and directions for pipe-laying: various fittings, illustrated in 16 figures.

II. TECHNOLOGY.—The Sizing of Cotton Goods; a paper read before the Society of Arts, by W. Thompson, F.R.S. A very full and clear description, embracing: An account of the process of weaving, explaining the object and utility of size. A table of sizing mixtures in which are enumerated all the substances used, (1) for giving adhesive properties to the size, (2) to give weight and body to the yarn, (3) for softening the size or yarn, and (4) for preserving the size from mildew and decomposition. Tests for these substances and directions for mixing, so as to obtain the results required. Proportions of sizing. Use of flour in size. Weighting materials, China clay and its substitutes. "Softenings" and oils for softening. East winds. Glycerin, grape sugar, mildew preventives, and tape sizing. "Slashing," packing, mildew, damaged goods, etc.—Notes on Garment Dyeing. Giving preparation of garments with cotton warps, green on garments with cotton warps, brown on the same, etc.

III. LIGHT, HEAT, ELECTRICITY, ETC.—On the Minute Measurements of Modern Science. By Alfred M. Mayer. Article IX. The dividing engine and methods of making accurate linear scales. 8 illustrations.

IV. NATURAL HISTORY, ETC.—Catastrophism, or the Evolution of Environment. An address by Clarence King before the Sheffield Scientific School of Yale College, New Haven, Conn.

V. AGRICULTURE, HORTICULTURE.—Pencils of Silver Nitrate.—The Black Poplar.—Tree Leaves as a Fertilizer.—Improving Pastures. —Lawns and Hay.—Thoroughbred Pigs.—Shall Country Houses have Cellars?

VI. MISCELLANEOUS.—The New German Patent Law: being the Full Text of the New Law for Patents, passed July 1, 1877, covering all the States of the German Empire.

Terms.—Scientific American Supplement, one year, postpaid, five dollars. One copy of Scientific American and one copy of Scientific American Supplement, one year, postpaid, seven dollars. CLUBS.—One extra copy of the Supplement will be supplied gratis for every club of five Supplement subscribers at $5.00 each.

All the back numbers of the Supplement, from the commencement, January 1, 1876, can be had. Price 10 cents each.

NOW READY.—The Scientific American Supplement for 1876, Complete in two large volumes. Over 800 quarto pages; over 2,000 engravings. Embracing History of the Centennial Exhibition. New Illustrated. Instructions in Mechanical Drawing. Many valuable papers, etc. Price five dollars for the two volumes, stitched in paper; or six dollars and fifty cents, handsomely bound in stiff covers.

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