268 Progress in Science. (April, | 
II0,000,000 to 120,000,000 gallons of water, with pumping engines to fill 
them to a level of 12 feet above the river. When full these reservoirs will 
contain ten to-twelve days’ water supply to the distri. The water from the 
reservoirs will run by gravitation through the new conduit to the filters at 
Ditton, which are in course of extension by the conversion of the reservoirs 
there into filter beds. The Chelsea Company are proceeding rapidly with the 
construétion of new filter beds at Ditton, and are laying down a new 30-inch 
pumping main between Kingston and Putney for the constant service supply, 
besides covering in a reservoir at Putney Heath—not hitherto in use—capable 
of containing 1,000,000 gallons of filtered water, to improve the supply of the 
high service. : 
Street Pavements.—Mr. Haywood, the Engineer and Surveyor to the Com- 
missioners of Sewers of the City of London, in a recent report on the 
different kinds of pavement now in use, states that, from observations taken, 
it was found that, of “falls on knees,” wood pavement had the greatest pro- 
portion, and that asphalt has the fewest of that class of accidents. Of falls 
on haunches, the asphalt had the largest proportion, and these accidents on 
it were very largely in excess of those on either of the other pavements, while 
the wood had the smallest proportion. Of complete falls there were fewest 
on wood and most on the granite, but the difference between the asphalt and 
granite was in this respect small. - It appeared generally that horses travelling 
on the wood pavement were on the whole subjected to falls of a character less 
inconvenient to the general traffic in the street, and also less likely to be 
injurious to the horses, than those travelling on the other two pavements, and 
that in this respect the ligno-mineral was superior to the improved wood 
pavement. It was also noticed that, whatever was the nature of the accident, 
the horses recovered their feet more easily on wood than they did on either 
asphalt or granite. On the average of the observations made, the granite 
was found to be the most slippery, the asphalt the next so, and the wood the 
least. The conditions of the different pavements varied, however, in some 
respect with the state of the weather. Further observations than have yet 
_ been taken appear necessary before any final and conclusive judgment can be 
given for or against any one class of pavement. 
Steam Economy.—On the 28th of January last Mr. Spence exhibited to 
a distinguished audience, at Stafford House, a plan by which he proposes to 
employ the heat of waste’steam as a substitute for fuel. This method is 
founded upon a discovery made by the father of the inventor, that steam 
liberated at atmospheric pressure, and passed into any saline solution haying — 
a boiling temperature higher than that of water, would raise this saline 
solution to its own boiling-point. In utilising the exhaust steam from a high- 
pressure engine, Mr. Spence brings it into contacé with a solution of caustic 
soda, which it will raise to a temperature of 375 degrees, or thereabouts, and 
the heated solution is then circulated through pipes in an ordinary boiler, and 
its heat is radiated for the purpose of generating steam in the place of heat 
derived from fresh fuel. . 
Brighton and Hove Gas-Works.—A paper on this subject was recently read 
before the Institution of Civil Engineers, by Mr. John Birch Paddon. The 
site of these works is the widest, most level, and highest part of a tra& of 
shingle lying between the sea and the canal forming the eastern entrance to 
Shoreham Harbour. This shingle was formerly arrested in its eastward 
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movement by the entrance-works to the harbour, but since the construction of 
the present westerly entrance it has been greatly wasted by the sea. Between 
1865 and 1870, in front of the site of the gas-works, the high-water mark ad- 
vanced landwards too feet. To obtain a deposit of shingle along the sea- 
front, aS a protection, two groynes were first constructed, and others were 
subsequently built along the coast to be protected. The foundations of the 
walls of the buildings are laid on concrete, and so extended as to make the 
proportion of the weight of the superstructure to the bearing surface of 
15 cwts. per square foot. The concrete bed under the retort benches is 7 feet 
6 inches thick. The retort-house is 286 feet 6 inches long and 80 feet wide. 
CdD Gee 
