Journal of the Franklin Institute, No. 700, April.—Prof. Coleman Sellers, mechanics: introductory. Abstract report of a public lecture exposing various fallacies.—W. Dennis Marks, initial condensation of steam cylinders.—W. E. H. Jobbins, an investigation locating the strongest of the bronzes. The tests were made with Thurston's recording testing-machine, and gave for the two strongest bronzes the following:—Cu57, Zn42, Sn1, and Cu56, Zn42, Sn2.—J. C. Hoadley, a tilting water-meter.—S. Lloyd Wiegand, cast-iron in steam-boilers.—G. M. Bond, standards of length and their subdivision. W. Dennis Marks, economy of compound engines. Final agreement cannot be reached until “a more complete and rational set of experiments are made on the compound engine than now exist.”—Dr. P. Frazer, reply to T. D. Rand's paper on the geology of Chester Valley, &c.