34 _ TECHNOLOGY. 
Pl. 3, jig. 138, shows the engine-house of the Diisseldorf and Elberfeld 
inclined plane, jig. 14 a plan of the same, fig. 16 a view from above of the 
main drum and parts connected therewith, and fig. 15 a cross-section on 
the line, o’ pv’, of fig. 16. Here the drums do not lie in the prolongation of 
the plane, as in pl. 4, figs. 9 and 16, but perpendicular to the same; 0, is the 
main drum, driven by the steam-engine ; from this drum the cable runs over 
the two inclined intermediate wheels, p and g, and thence over the rollers, 
cr (fig. 15), to the railroad track. gs. 17, 18, and 19, are the cable-rollers, 
as already more particularly described. In jig. 14 are seen upon the left 
the two steam-engines which operate upon the crank-axle, /, upon the other 
end of which is the fly-wheel, n, and the main drum; 0bcde, are water 
and steam-pipes to and from the boiler-room and the well, a. 
5. SusPENDED Rairoaps. These were first suggested in England by 
Palmer, but have never been introduced to any extent. A road of this kind 
was used at the building of the military works at Posen, and as its con- 
struction is peculiar, we will give a short description of it. 7g. 21 is a 
side-view of the car and road; jig. 22 an end view of the car, with a section 
of the rail. At yin jig. 21 is seen the end of a second car attached to the 
first. The road consisted of a continuous wooden sleeper or beam, B, hay- 
ing an iron rail, c, upon its top, and supported upon posts, a. The cars 
were balanced upon each side of the road, and were supported upon the 
top rail, c, by a grooved roller, u. To the sides of the posts, a, were 
secured bars, a, having each an iron rail, 3, in its centre, against which 
the body of the cars rests either with or without friction-rollers. Where 
horses are the moving power, they are to travel one upon each side of the 
road. 
6. AtmospHERIC Ratrroaps. The many accidents which occurred when 
railroads were first introduced, and the great expense of running locomo- 
tives, made it very desirable that the latter should be dispensed with, and 
that a cheaper and safer motive power should be found to take their place. 
Compressed air was thought of, and experiments were made to render this 
available, but without success. Rarefied air was then thought of; and 
Vallance, an Englishman, suggested a large hollow cylinder of sufficient 
capacity to contain the whole train of cars within its interior; in advance of 
the train, and attached thereto, there was to be a piston sufficiently large to 
fill the cylinder, from one side of which the air was to be exlausted, and 
the pressure of the air upon the other was to drive it along, together with 
the train attached to it. The proposition carried upon its face entire imprac- 
ticability, and was never acted upon. 
The same idea was however afterwards carried out with considerable 
modification, and an experimental tube was laid near London, 1200 feet 
long and 9 inches in diameter; a 16-horse steam-engine was used to 
pump out the air from the tube. The result of this experiment being 
entirely satisfactory, the system was put into practical operation in Ireland 
upon a branch of the Dublin and Kingstown Railroad. This branch, with 
the Croydon and South Devon Railroads in England, and a few minor 
trials in France, are the only ones ever constructed upon this plan. The 
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