Scientific Serials

Abstract

THE article in the Quarterly Journal of Science for July which will be most read, is by the editor, Mr. Crookes, “Experimental Investigation of a New Force,” on which we have already commented. “The Dawn of Light Printing” gives a sketch of the early discoveries in photography of Niepce, Fox Talbot, and Daguerre. Mr. F. C. Danvers gives an account of the present condition of inventions for Pneumatic Transmission, with mathematical formulae for the power obtained. Under the title “Where are the bones of the Men who made the unpolished Flint Implements?” Mr. Pengelly argues that we know so little about the effect of various climatic and atmospheric conditions on the bones of man and the lower, animals, that it is rash to conclude, because human remains are not, as a rule, found associated with flint implements and animal remains in the bone caves, that therefore they cannot have been originally deposited along with them. He also cites a number of unquestioned instances in which the bones of man have been found in such situations, to all appearance contemporaneous with the animal remains. Even were such evidence entirely wanting. Mr. Pengelly considers the flint implements themselves absolutely conclusive proof of the contemporaneity of man with the mammoth and the extinct cave-animals. One of the most valuable and interesting articles in the number, though a short one, is entitled “A New Mechanical Agent: A Jet of Sand.” Mr. B. C. Tilghman, of Philadelphia, appears to have solved the problem of cutting or carving, mechanically, hard substances, such as stone, glass, or hard metals, in an expeditious, accurate, and economical manner. He has shown that a jet of quartz and thrown against a block of solid corundun will bore a hole through it one and a half inches in diameter and one and a half inches deep in twenty-five minutes and this with a velocity obtainable by the use of steam as a propelling power at a pressure of 300lbs. per square inch. The apparatus used for grinding or cutting glass or stone is described in detail. By covering parts of the glass surface by a stencil or pattern of any tough or elastic material, such as paper, lace, caoutchouc, or oil paint, designs of any kind may be engraved upon in. In his abstracts of the Progress of Science, the editor now confines himself entirely to the physical branches.