### Compound and non-compound engines, steam-jackets, etc

Charles E. Emery
1875 Journal of the Franklin Institute
Civil and Mec]tanical Engineering. smaller pulley, as the numbers of revolutions are in an inverse ratio to the radii of the pulleys. That is, R nl Hence Rn ~ Rln 1. R~ n If the belt is made up of two layers or thicknesses, so that such a belt of the same width as a single one contains the double cross section, we still may apply the upper formula, if we multiply it by ~}, owing to the greater stiffness of the belt. ;Example. In order to transmit 4 horse powers, we have a pulley 1 ft. 8 in. by
more » ... ley 1 ft. 8 in. by 120 revolutions per minute. What should be the width of the belt'.~ N:4; R:l~ft.; n=120. 250N For the single belt we should have received: w : 3-2 X 3½ = 5 inches. (4 C.) It should be here observed that in the above comparison of the results of experiments with the steamer Bache and of the revenue steamers, the former shows more inferiority than can be attributed simply to the difference in size, and we are of the opinion that it was due somewhat to the quality of the steam furnished by the boilers. The boiler of the Baehe was constructed to give a high evaporation, and the combustion was so slow that the steam in the steam-chimney received practically little heat from the escaping gases. On the revenue steamers, the boilers were made to develop the maximum power for a given space--the tubes were shorter, the draft freer, and the experiments being tried at maximum power, the gases passed through the steam chimney at a higher temperature than on the Baehe, so that