HYDEAULIC POWEE TEANSMISSION 



713 



four sections, and the section in which the abnormal flow is occurring is 

 indicated by the behaviour of the pressure gauge connected with that 

 circuit. The stop valves on this main are then shut down in succession 

 until the defect is discovered, either by the aid of an iron rod which 

 conveys the sound of the escaping water to the ear, or by applying a 

 pressure gauge. Usually the former method is adopted. 



All the pressure water is metered by Kent's high pressure rotary meters 

 before reaching the consumer, some 97 per cent of the water delivered by 

 the pumps being registered on these meters. 



The following abbreviated scale of charges, which came in-to force at 

 the end of 1907, may be of interest, as indicating the probable cost of 

 such power. 1 



Power water taken in excess of 300,000 gallons per quarter is charged 

 2s. per 1,000 gallons for the excess quantity so taken, and where the con- 

 sumer agrees to take a minimum quantity of 500,000 gallons, the price 

 attains a minimum of Is. 3d. per 1,000 gallons for a minimum of 3,000,000 

 gallons per quarter. 



Assuming an efficiency of 75 per cent for the consumers' machinery, 

 this gives a cost per B.H.P. hour varying from 1'562 shillings, in the 

 case of the smallest consumers, to *156 shillings or 1'875 pence in the 

 case of the largest. Power water for motors running on an average 6 

 hours per day is charged at Is. Qd. per 1,000 gallons. 



The following list of costs of buildings and plant of this station may be 

 of interest : 



Buildings, tanks, girders, columns, etc. . 

 Boilers, stokers, economisers, elevators, etc. 

 Engines, pipes, valves, etc. . 



Total 







16,835 



4,023 



20,614 



d. 

 

 

 6 



41,472 10 6 



In the London installation the water is taken from the river or from 



1 For these particulars the author is indebted to Mr. L. Holme Lewis, tne chief engineer to 

 the Corporation Power Supply Department. 



