Steam:
Its Generation and Use

rejected, in which the thermometer scale was seen to move by bringing the hose too near the instrument. The results were calculated from the records of the remaining sixteen experi- ments, on the following basis : Let W = original weight of water in calorimeter. Let w = weight of water added by heating with steam. Let T = total heat in water due to the temperature of steam at observed pressure. Let H — total heat of steam at observed pressure. Let I - latent heat of steam at observed pressure. Let t ” total heat of water corresponding to temperature of water in calorimeter. Let t" ■ total heat in water corresponding to final tempera- ture of water in calorimeter. Let E — heating efficiency of the steam furnished, compared with saturated steam between the same limits of temperature. Let Q ■=■ quality of steam explained hereafter. Then E When Q > i, the number of degrees steam is superheated — 2.0833 ( Q — 1 )• In the present case Q = .98955. Per centage of moisture in steam — 1.045. This is practically dry steam, and equal in quality to that furnished by boilers of any type not provided with superheating surface. The ex- periments show, in a gratifying manner, that you have succeeded in overcoming a great difficulty often experienced with boilers constructed of a combination of small chambers to reduce the danger of explosion. The deficiency of ordinary boilers in furnishing dry steam is little known, though the economy is materially affected. Engine Trials. The preliminary trial of engines gave the fol- lowing results : W (/' — /) w ( H — /') Babcock & Wilcox Boilers at Yngenio, Central Ysabel, Manzanillo, Cuba, 1,000 H, P The value of E was ascertained by the formula separately for each experiment. The average value was .9916, showing that the steam lacked but °f 1 Per cent-of the quantity of heat re' quired for producing perfectly dry or saturated steam between the same limits of temperature. The value of Q may be found directly from the following equation : Q-f ...........')(T-'))........(») or, from the average of the heating efficiencies, by the following : Then when Q < 1, the per centage of moisture in steam — 100 (1 — Q). Duration of experiment, . . . .4.1 hours. Average steam pressure in boilers, . . 93.94 pounds. Average vacuum in condenser, . . . 21.5 inches. Average revolution of engine per minute . 64.492 Water evaporated per hour, . ‘ 8830.244 pounds. Average initial pressure in steam cylinders, 84.425 Mean effective pressure in cylinders, . 30.1275 Average point of cut-off, .... .129 stroke. Average indicated H. P. (both engines), . 292.613 Maximum H. P. shown by a complete set of diagrams,...................315-580 Water per indicated horse-power per hour, 30.177 pounds. The steam pipe was 131 feet long and other conditions were unfavorable for the economical development of power in the engines. It is, in fact, popularly supposed that this class of engines develops a horse-power for % the quantity of steam required in this case. The duration of the boiler experiment was 12 hours and 37 minutes, of which full}’ 13 minutes 83