Mr. Collingwood stated that of a rail only a section of 3/8 square inch was pressed by the wheel of a locomotive, the effect being to cause this portion to act like a wedge, and thus to contribute to the disintegration of the rail. He also exhibited a hook which had been used to hoist stones of 10 to 12 tons, and then suddenly broke with a weight of only 61/2 tons. It had been worn from a thickness of 2 inches to 1-7/8. The pressure at the upper surface crowded the particles and caused them to act as wedges. Their fracture was crystalline, while that of the lower surface, which parted more slowly, was fibrous. Professor Egleston asserted that there was no such thing as fibrous iron; what appeared so being simply crystalline with the ends drawn out. A sharp blow would cause this to fall off and show the crystalline structure beneath. The discussion was continued by Professors Trowbridge, Egleston, and Newberry. C. F. K. * * * * * FORMATION OF IODIFORM.--All mixtures in which alcohol and iodine enter in combination with any alkali forming colorless solutions go in part to the formation of iodiform. Even chloroform and iodine, forming a colorless solution, give rise to the same product.--_L. Myers Connor._ * * * * * SANITARY SCIENCE IN THE UNITED STATES. The following is an abstract of a paper on the Present and Future of Sanitary Science in the United States, read by Professor Albert R. Leeds, of the Stevens Institute of Technology, before the New York Academy of Sciences at their meeting, November 11th, 1878: