HYDKATJLIC KAM.

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vieles for the passage of the water into the macliine by easycurves, and not by sliarp angles, whieh produce sliocks andconsequent loss of energy. There are several hydraulic ramsnow manufaetured whieh comply with these conditions, andwhich reach an efficiency of 65 per cent., and even more.About 4 inches is the largest size tliat the injection-pipe of aram should be made for safe working.

In the Transactions of the American Society of Engineers , Mr.Weston gives the results of some useful experiments which hemade to ascertain the effeet produced by the sudden closing ofvalves against water flowing in pipes. Lines of pipes from 1inch to 6 inches in diameter were laid above ground, and an airvessel was provided which could be connected or disconnectedas required. The supply was drawn from a 24-inch rnain bya 6-inch pipe. The average static pressure in the pipe was70 lbs. per square inch. In the first series of experiments thewater flowed tlirough lengths of pipes of different diameter,tlius:—111 feet of 6-inch pipe, 58 feet of 2-ineh pipe, and99 feet of l-|-inch pipe, to a 1-inch outlet pipe, with a ^-inchorifice. In this case the velocity was OTS of a foot persecond in the 6-inch pipe, and 5'36 feet in the 1-inch pipe.Upon closing the orifice (which was effected in 0T6 of asecond) the force of the ram in lbs. per square inch was129-2 lbs. in the 1-inch pipe, 127 lbs. in the 1-^-inch pipe,and 14'5 in the 6-inch pipe. At the dead encl of a separate2-^-inch braneh-pipe (leading out of the 6-inch pipe at adistance of 300 feet), the force of the ram was 18'8 lbs.With orifices of |th, T ^-ths, Ith, and T^ths of an inch, andwith velocities of 1-06, 2-57, 5-36, and 6-75 feet per second,the rams in the 1-inch pipe exerted a force respectively of 26’9,72-8, 129-3, and 158-7 lbs. per square inch. In the 6-inchpipe, with ^--inch and ^-inch orifices, and with velocities of0T5 feet and 0'53 feet per second, the rams exerted a force of14-5 and 517 lbs.

Mr. Weston made another series of experiments on an