4 



Ward's Patent for Improvements 



inlet and one outlet valve at each end; but I prefer tliat, 

 instead of each of the valves before described, more 

 should be used ; for example, three inlet and three outlet 

 valves in the top of the cylinder, and three inlet and three 

 -outlet valves in the bottom of the cylinder. 



Another part of my improvements consists in the com- 

 bination of large vessels, or reservoirs, with air-pumps, so 

 that such vessels, having been previously exhausted, shall 

 assist the pumps in the exhaustion of the traction- tube, 

 and that the steam-engine, or other motive power used to 

 actuate the pumps, may be of much less power than would 

 be required, if unassisted by the reservoirs, or that the 

 traction tube may be exhausted with much greater 

 rapidity than by the methods which have hitherto been 

 used. 



With respect to this second part of my improvements, 

 I will remark, that reservoirs, previously exhausted, have 

 been used in working experimental models of atmospheric 

 railways, and have also been proposed as advantageous for 

 the actual working of atmospheric railways; but such 

 reservoirs were, or are, intended to be put into immediate 

 communication with the traction tubes, by doing which 

 considerable power is lost, as much more power is 

 required to exhaust the residual than the first portions of 

 air from any vessel, and such reservoirs would require to 

 be exhausted to a much higher degree of rarefaction than 

 would be by them produced in the traction-tube, and the 

 air from the mains, which might otherwise be exhausted 

 by a comparatively small power, would take the place of 

 the portion of the air which had been exhausted from the 

 reservoir by a very great expenditure of power. I com- 

 bine pumps with reservoirs, so that one of the pumps 

 which may have been used in exhausting the reservoirs 

 may, by a slight change of its communication with the 

 reservoirs, be employed as an air-engine, in order that the 

 power exerted by the air passing from the traction-tubes 

 to the reservoirs may be made effective in assisting the 

 steam-engine, or other motive power, in working another 

 pump ; and also, that when the air in any of the reservoirs 

 becomes of greater density than the air in the traction- 

 tube, the air may be pumped from the traction-tube into 

 such reservoir, with much less expenditure of power than 

 in pumping from the traction- tube into the atmosphere. 



1 do not mean to confine myself to any precise or 



