Page:Popular Science Monthly Volume 8.djvu/390

376 and the problems solved are precisely such as arise for solution every day in the workshop of the mechanic or the amateur handicraftsman. We cannot better indicate the character of the work than by naming a few of the heads under which the matter it contains is arranged. Thus we have the heading "Miscellaneous Tools, Instruments, and Processes," which includes hints on the microscope, hydraulic press, drills, screw-propeller, etc.; "Cements, Glues, Varnishes," "Solders," "Metals," "Steam-Engine," "Fire-arms," "Clock-work," "Glass," "House and Garden," "Drawing and Modeling," "Photography," "Musical Instruments," "Electricity and Telegraphing."

is an address to a graduating class of the Stevens Institute of Technology, by the Professor of Mechanical Engineering. Prof. Thurston, in the first place, recalls to the minds of the young engineers the rare educational advantages they have enjoyed at the Institute: very full instruction in mathematics and physics; in modern languages; the English language and literature; principles of engineering, and the practice of the arts connected therewith. So far, the students have been working at the foundation; the superstructure they must build by their own efforts. The professor exhorts them to be wide-awake, observant, conscientious, true to their clients, progressive, radical in theory but conservative in practice, and diligent in study.

this work the author well sustains the reputation he has long enjoyed of being a profound thinker. It contains the results of Mr. Reemelin's meditations during many years—meditations reduced to writing from time to time without any definite intention of publishing—upon the laws and phenomena of politics. As reading corrected his views, these detached meditations were amended, and gradually the purpose ripened to gather them together and put them in permanent form.

first of these papers is a brief description of the physical and chemical characters of a new mineral which, according to the author, is closely related to the sesquihydrates of iron. It contains about seventy-five per cent, of sesquioxide of iron, seven per cent, of silica, and thirteen per cent, of water, the remainder being alumina.

The second paper is a full account of the physical properties and chemical constitution of two new varieties of vermiculite, a mineral having a granular, scaly structure, and composed mainly of silica, alumina, magnesia, iron, and water. Its name is derived from the circumstance that, when heated, its scales open out into worm-like threads.

is a preliminary paper describing, with measurements, the external parts of a foetal manatee, a little less than three inches long; and a fœtal cetacean but a trifle longer, and supposed to be the embryo of a porpoise or dolphin. Then follow some remarks on the affinities of the sirenia, in which the author, after referring to the present state of opinion on the subject, gives reasons for viewing them as near relations of the ungulates.

analyzed some fragments of the great Iowa meteorite of 1876, and the results of his investigation are given in the pamphlet before us. He finds the spectrum of the gases contained in the meteorite to closely resemble that of several of the comets. Other facts are cited to show that a comet is simply a meteorite of considerable magnitude, or a swarm of many of lesser size.