SPECIFICATION OF THE PATENT 



GKANTED TO 



WILLIAM SYKES WAED, 



OF LEEDS, IN THE COUNTY OF YORK, GENTLEMAN. 

 FOR 



IMPROVEMENTS IN EXHAUSTING AIR FROM TUBES 

 OR VESSELS FOR THE PURPOSE OF WORKING 

 ATMOSPHERIC RAILWAYS, 

 AND FOR OTHER PURPOSES. 



SEALED JUNE 25, 1845. 



WITH AN ENGRAVING. 



To all to whom these presents shall come, &;c., &c.— 

 One part of my improvements relates to the arranging 

 and working of the valves of air-pumps for the purpose of 

 exhausting the air from the traction-tubes of atmospheric 

 railways, and also for the purpose of exhausting air from 

 any vessels or tubes upon a large scale. I will here remark 

 that, in using air-pumps as hitherto practised for working 

 atmospheric railways, power is lost in opening the inlet 

 and outlet valves, by the action of the air entering into, 

 and expelled from, the cylinder of the pump, and the 

 violence with which such valves close is objectionable. 

 Mechanical contrivances, or systems of gearing, have been 

 used to work the valves of air-pumps; yet the methods 

 hitherto employed or suggested for working the outlet 

 valves of such air-pumps are either very complicated, or 

 would fail in opening such outlet valves at the proper 

 period of the stroke of the pump. 



My method of constructing air-pumps is such, that the 



B 



