92 



REPORT 1844. 



The engine made 8 strokes in 63 seconds. 



The various elements of the motion of the piston of the engine are arranged 

 below in a tabular form. 



In column B. are stated certain periods of time from the commencement 

 of the stroke, after which periods of time the positions of the piston indicated 

 in column A. are respectively attained. 



Column C. represents the approximate velocity of the piston in each cor- 

 responding position. 



It will be evident that the numbers in column A. are equivalent to the 

 abscissae of the curves in Plates XXVI. and XXVII., while the column B. re- 

 presents the ordinates in Plate XXVII., and column C. those in Plate XXVI. 



The times are given in these tables only as far as the hundredths of a se- 

 cond, and the velocities to the twentieth part of a foot per second ; but the 

 delicacy of the machine enables them to be calculated, when necessary, to a 

 much greater nicety. 



Tables of the Elements of the Motion of the Piston of the Cornish Pumping 



Engine at the East London Water Works, Old Ford. 



Table I. Table 11. 



A slight oscillation of the calculated velocity is found to occur on either 



equilibrium valve is opened by the plug-rod at the end of the in-door stroke, and the engine 

 immediately returns. Buc in the Old Ford engine this valve is worked by a second cataract, 

 and therefore a short pause is often allowed. 



