Scientific American Supplement, No. 415, December 15, 1883 eBook

This eBook from the Gutenberg Project consists of approximately 102 pages of information about Scientific American Supplement, No. 415, December 15, 1883.

[Illustration:  FIG. 5]

The dynamometer is now more powerful in absorbing work than in the form Fig. 3.  As to the practical construction of the brake, the author thinks that simple wires for the flexible bands, lying in V grooves in the pulleys, of no great acuteness, would give the greatest resistance with the least variation of the coefficient of friction; the heat developed being in that case neutralized by a jet of water on the pulley.  It would be quite possible with a pulley of say 3 feet diameter, and running at 50 feet of surface velocity per second, to have a sufficiently flexible wire, capable of carrying 100 lb. as the greater load, Q. Now with these proportions a brake of the form in Fig. 3 would, with a probable value of the coefficient of friction, absorb 6 horse power.  With a brake in the form Fig. 4, 8.2 horse power would be absorbed; and with a brake in the form Fig. 5, 8.8 horse power would be absorbed.  But since it would be easy to have two, three, or more wires side by side, each carrying its load of 100 lb., large amounts of horsepower could be conveniently absorbed and measured.

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This stove consists of two or more superposed pipes provided with radiators.  A gas burner is placed at the entrance of either the upper or lower pipe, according to circumstances.  The products of combustion are discharged through a pipe of small diameter, which may be readily inserted into an already existing chimney or be hidden behind the wainscoting.  The heat furnished by the gas flame is so well absorbed by radiation from the radiator rings that the gases, on making their exit, have no longer a temperature of more than from 35 to 40 degrees.

[Illustration:  SEE’S GAS STOVE.]

The apparatus, which is simple, compact, and cheap, is surrounded on all sides with an ornamented sheet iron casing.  Being entirely of cast iron, it will last for a long time.  The joints, being of asbestos, are absolutely tight, so as to prevent the escape of bad odors.  The water due to the condensation of the gases is led through a small pipe out of doors or into a vessel from whence it may evaporate anew, so as not to change the hygrometric state of the air.  The consumption of gas is very small, it taking but 250 liters per hour to heat a room of 80 cubic meters to a temperature of 18 deg.  C.—­Revue Industrielle.

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The number of persons killed by wild animals and snakes in India last year was 22,125, against 21,427 in the previous year, and of cattle, 46,707, against 44,669.  Of the human beings destroyed, 2,606 were killed by wild animals, and 19,519 by snakes.  Of the deaths occasioned by the attacks of wild animals, 895 were caused by tigers, 278 by wolves, 207 by leopards, 356 by jackals, and 202 by alligators; 18,591 wild animals and 322,421 snakes were destroyed, for which the Government paid rewards amounting to 141,653 rupees.

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Scientific American Supplement, No. 415, December 15, 1883 from Project Gutenberg. Public domain.
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