132 REPORT—1849. 
per week for each of its inhabitants. It has been objected to macamadized roads 
that the draught upon them is heavier than upon pavement; and with carriages 
altogether similar this is the case, and especially so with vehicles travelling slowly. 
But it must be remembered that the proportion of the draught is only one of the 
circumstances by which the labour of the horse is to be estimated. Another very 
important consideration is the surface which gives the horse the safest footing; and 
his footing on pavement is so much less secure than upon a good broken stone road, 
that he does not receive the full advantage of the smaller draught. Again, carriages 
—especially those travelling quickly—are exposed to much more violent concussions 
upon pavement than upon a smooth macadamized road: consequently, not only 
must the carriages be stronger and therefore heavier, but the increased frequency 
and violence of the concussions consume a larger portion of power, which goes far 
to counterbalance the diminished friction. There can be no doubt that the wear and 
tear of both horses and vehicles is far greater upon pavement than upon mac- 
adamized roads. In reckoning the real cost of a road, all expenses attending its 
use should be calculated; and if this were done, pavement would be perceived to be 
exceedingly expensive. Carriages roll so smoothly over a well-maintained mac- 
adamized road, ard horses are so little injured either by falls or strains, that I con- 
ceive the wear and tear upon them is not half of what it is on pavement. 
On a Method of supplying the Boilers of Steam-Engines with Water. 
By W.Syxes Warp. 
Mr. Ward’s suggestion was to use a small supplementary pumping-engine, having 
a working cylinder with valves so arranged that the piston may be put in motion by 
either steam or water passing through it, to be supplied with steam by a steam- 
pipe, the entrance to which is somewhat narrow, and inserted in the boiler to be 
supplied a little above the level at which it is desired to maintain the water therein. 
Such aperture should also be about the centre of a marine boiler. The working 
cylinder should be attached to a pump of such size as to be easily worked by the 
pressure of the steam. The exit-pipe of the steam-cylinder must communicate with 
the inlet-pipe of the pump, so that if the cylinder be actuated by steam, the steam 
will be condensed, and its heat communicated to the water to be supplied to the 
boiler ; or if the working cylinder be worked by water proceeding from the boiler,a __ 
considerable part of such hot water will be returned by the pump. The mode of — 
operation of such apparatus will be, that whenever there is a working pressure of 
steam in the boiler, the apparatus will be in action; but if the level of the water be 
below the aperture of the small steam-pipe, the action will be moderately rapid, and — 
a supply of water be pumped into the boiler; and when the water in the boiler rises 
to the aperture, this being small, will be as though choked by the water, which will — 
be forced through the working-cylinder, moving the piston and pump very slowly; 
a portion of the water thus escaping from the boiler will be returned by the pump. — 
Such last-mentioned action cannot continue long, inasmuch as the level of the water 
must be reduced ; therefore the average level of the water in the boiler will be, with — 
slight oscillations, maintained at the height of the aperture of the steam-pipe. : 
On Chain Pipes for Subaqueous Telegraphs. By ¥. Wuisnaw. 
Three links of a full-sized pipe, for enclosing the wires of electric telegraphs in — 
crossing rivers, &c., were laid before the Section. As the title implies, the pipe is 
formed by so many links connected together by sockets. Each link varies, accord- 
ing to circumstances, from 18 inches to 24 inches in length, and from 1 inch 
to 2% inches internal diameter, according to the number of wires to be enclosed. 
These pipes, being of wrought iron, are exceedingly strong, and are required merely 
as a protection to the wires, which are previously insulated by means of gutta 
percha. Pipes of somewhat similar construction are laid under the Rhine and other 
rivers in Prussia, where the under-ground system of telegraph is adopted by the 7 
Prussian government (already to the extent of 1200 miles), although many of the — 
railway companies suspend the wires between posts, as practised in Kngland, — 
America, France, &c. y 
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