This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1894 Excerpt: ...of section of stream in square inches. VJ W3 Then foot-lbs. per second =----X W = 0-082697--; 644 A2 W3 or foot-lbs. per mutute = 4-96172--. A2 W3 Therefore the IIP. of jet was nearly „„„--. J J 665 A2 It was only necessary therefore to catch and weigh the water which issued in 5 or 10 minutes from a suitable nozzle and estimate the rate of discharge. That and the area of the jet were all the data required. If the nozzle was properly formed, there should be no perceptible contraction after the jet left it. Where there was a vena contractu, the nozzle might be considered as not completely filled by the jet, and the formula would give too low a result unless the section of the stream was measured at its narrowest part. If desired, the constants could readily be corrected for temperature, supposing that to differ materially from 52-3 F. He was rather surprised to see no mention of the Rigg hydraulic engine, having been under the impression that it was specially adapted for hydraulic-power supply. Mr. Ellington, in reply to the Correspondence, stated that Mr. Ellington, experiments wlth the Pelton wheel and dynamo were in progress; therefore at present he was unable to give results. So far as they had gone, they indicated that an efficiency of 66 per cent. could be obtained at full load. The efficiency of the Pelton wheel varied only slightly at different loads and constant speed, and, therefore, the combined efficiency at varying loads depended principally on the construction of the dynamo. Interest and depreciation on the special capital expenditure would have to be added to the hydraulio power cost, but if the dynamo were used to supply single blocks of buildings there would be no additional cost for mains. The rate mentioned of 2s. per 1,0...