Chap. XVIII.

SUPTLY OF TOWN ’S WITH WATER.

1213

By this means the sediment will be carried off, and the water pass through quite cleaiagain in a few hours: the valves, S, should then be lowered, the stop-cocks opened,and the operation of filtering will again proceed as above described. The cost of thisfilter was 600 pounds, and the quantity of pure water produced regularly every 24 hoursis on an average 106,632 cubic feet.

We have already described other methods which have been adopted by the several watircompanies for the purification of water, to which we must refer.

Cost of raising Water, as given to the Commissioners of Inquiry into the State of LargeTowns by Thomas Wicksteed, the engineer to the East London Waterworks.

1st. A single pumping engine, made by Boulton and Watt in 1809, working 10} hoursper day, 6 days per week, mean power 29.} horses : quantity of water raised per day equal to612,360 gallons 100 feet high : the cost of coal 12 shillings per ton; in the estimate, allcharges, working the engine, coals, labour, and stores, are included, but none for interestupon outlay, or repairs of machinery and buildings.

s- d.

Cost of raising 1000 gallons 100 feet high 0 0\543

Or 22,099 gallons 100 feet high • - 1 0

This estimate is upon an average of two years’ working.

2nd. Two single pumping engines, by Boulton and Watt in 1809, working 24 hoursper day, 7 days per week, mean power of each engine 30} horses ; quantity of waterraised per day, 2,922,480 gallons 90 feet high; the cost of coals 12s. per ton. Labour,horses, See., taken as before. The estimate upon an average of 10 years’ working.

s. d.

Cost of raising 1000 gallons 100 feet high - - 0 0*358

Or of raising 33,519 gallons 100 feet high - - - 1 0

3rd. Two single pumping engines made by Boulton and Watt, one in the year 1816,and the other in 1828, working 12 hours per day, 7 days per week, mean power of eachengine 76 horses, quantity of water raised per day 3,601,116 gallons 100 feet high; costof coals 12s. per ton. Labour, horses, &c. as before. The estimate upon an average of 10years’ working.

s. d.

Cost of raising 1000 gallons 100 feet high - - - 0 0*333

Or of raising 36,036 gallons 100 feet high - - - 1 0

4th. One single pumping engine made by Harvey and Co., upon the expansive principle,in the year 1837, working 24 hours per day, and 7 days per week, mean power 95} horses;quantity of water raised per day 4,107,816 gallons 110 feet high; cost of coals, 12s. perton ; labour and stores as before ; the estimate upon an average of four years’ working.

s. d.

Cost of raising 1000 gallons 100 feet high - - - 0 0150

Or, of raising 80,000 gallons 100 feet high - - - 1 0

The foregoing statements show a great variation in the cost of raising water withdifferent engines. The comparison, however, is favourable to those on the old plan, and ofthe best make. The following table expresses the variation more clearly : —

£.

To raise 160,000,000 gallons of water 100 feet high, it would cost,according to the first statement, -

second ditto -

third ditto -

fourth ditto -

362

238

222

100

A very great economy in the power employed in pumping water might be effected bythe use of the expansive engine and plunger pump, the advantages of which have beenacknowledged in the mines of Cornwall for more than thirty years: this principle, Mr. T.Wicksteed observes, was first introduced into waterworks in the year 1837, when an enginewas set up at the East London 'Waterworks, and is now working most satisfactorily,having from the time of its first starting continued to raise 225 barrels of water, with thesame quantity of coals required by the best engine on the works, made upon the old con-struction, to raise 100 barrels ; since that time another large engine of the same descriptionhas been erected at the Southwark waterworks, which acts in an equally satisfactory manner.

There is also another advantage derived from the introduction of this new engine,namely, that the same quantity of water may be raised from 2} to 5 times the height, bythe consumption of a given quantity of coals ; and as the size of the pipes depends uponthe velocity of the water passing through them, and that velocity increases as the squareroot of the head of water, so by increasing that four times, the dimensions of the pipesmay be reduced to one-half; the chief item in the expenditure in new works may conse-quently be reduced one-half, and less capital be required.