## Table For Finding The Consumption Of Coal Per Hourin Steamers Either Paddle Or Screw (The Same Screw Being Used Throughout,) At Any Kate Of Speed, The Consumption For A Particular Rate Being Known. (At A Given Amount Of Coal, The Engineer May Determine The Most Prudent Rate Of Engine For Reaching Next Coaling Port.)

Engineer's and Contractor's Pocket Book, London.

 Speed. Consumption of Coal. Speed. Consumption of Coal. Explanation. 3 .216 9 5.83 The speed for the consump-tion of a unit of coal is supposed here to be5, which may| be 5 miles or knots, or5 limes any number of miles or knots; then if 5 of such number of miles require 1 unit of coal per hour, 9 of such mills will, by the table, required 5.83 units of coal, and 3 of them .216 units of coal. 3 1-2 .313 9 1-2 6.86 4 .512 10 8.00 4 1-2 .729 10 1-2 9.26 6 1.000 11 10.65 5 1-2 ] .331 11 1-2 12.15 6 1.728 12 13.82 6 1-2 2.197 12 1-2 15.61 7 2.744 13 17.58 7 1-2 3.375 13 1-2 19.68 8 4.096 14 2195 8 1.2 4.910

It will be evident that this Table is calculated on the principle that the horse power varies very nearly as the cube of the speed; the enormous increase of consumption at increased velocities is in fact a little greater than that shown by the Table.

The advantages indicated above to be obtained at low velocities are evidently independent of those obtained at those velocities by using the steam expansively.