Page:Popular Science Monthly Volume 51.djvu/139

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strong efforts now being made to develop a vehicle that shall propel itself, and the measure of success already achieved, promise the early attainment of an advance in locomotion as great as that afforded by the introduction of the safety type of bicycle. A good idea of the mechanical principles that are being employed in the solution of the problem may be gained from a translation of a recent book by a French engineer. Of the four kinds of motor that have been applied to self-propelling vehicles—steam, electric, compressed air, and naphtha—the author has by far the most hopes of the last, and gives most space to this type in his book. His early chapters are devoted to a statement of the mechanics of steam and other gases, and he gives here also the theory of the electric motor. In describing the various systems of steam traction he gives first place to the Serpollet generator—the only generator of steam allowed for traffic in the large cities of France. Other steam motors that find place here are the Le Blant, De Dion & Bouton, Bollée, Filtz, Rowan, and Francq. Compressed-air autocars are represented by the Popp-Conti tramway and the Mékarski system. M. Farman is naturally most familiar with motor wagons of European origin, but he has inserted such accounts as were accessible to him of the American types. Among petroleum motors he ranks as king the one invented by the German Daimler, which is employed in the carriages of Panhard & Levassor, Peugeot, Gautier, and other builders. He gives a full description of this and describes also the Roger car with the Benz motor, the Gladiator auto-cycles, the Duryea, Kane-Pennington, Tenting, and Delahaye cars, and several machines so far used only for agricultural or other industrial purposes. Electric carriages are represented by the Jeantaud, Morris & Salom, and Bogard. His concluding chapter deals with lubrication, tires, bearings, and other details. Over a hundred carefully drawn figures and diagrams illustrate the volume.

The notes which the reader will find in Miss Merriam's attractive volume were taken at Twin Oaks in southern California. The author is a bird enthusiast who, before going to the Pacific coast, had known only the birds of New York and Massachusetts. "Every morning right after breakfast" she has her horse brought round, and together in silent sympathy she and Canello, the faithful patient little broncho, go the rounds of the valley, getting acquainted with the birds as they come from the south. Canello liked well to "watch birds in the high alfalfa under the sycamores, but when it came to standing still where the hot sun beat down through the brush and there was nothing to eat, his interest in ornithology flagged perceptibly." Then after dinner the author strolls through the trees to get a nearer view of the nests. The white egret, the green heron, the spotted sandpiper, the valley quail, are as fascinating to Miss Merriam as are the ants to Sir John Lubbock. Her description of all the birds is marked by a charming simplicity and by a beautiful use of English. She is in touch with Nature, with an eye for color, an ear atune to melody, and intellect clear and clean. It is a pity that we have not more such books as this and more such women as the authoress. We can imagine no better mental tonic than a ride on horseback in the early morning while the dew is on the grass, with the authoress as a chaperon and teacher of bird lore, for the weary city woman who needs to be lulled back to rest and get mental and physical health on the bosom of Mother Nature.

Prof. Ramsay, who was associated with Lord Rayleigh in the remarkable discovery of argon, has written a popular historical sketch of the several investigations that have given us our present knowledge as to what air is composed of. He begins with the work of Robert Boyle, who published about 1650 his Memoirs for a General History of the Air, and proceeds with the less known labors of John Mayow and Stephen Hales.