298 THE SCIENTIFIC PAPERS OP 



In the discussion of the Paper 



"ON THE PROGRESSIVE APPLICATION OF 

 MACHINERY TO MINING PURPOSES," 



By T. J. TAYLOR, 



MR. C. W. SIEMENS * remarked that, in reference to the com- 

 parison between the beam pumping engines and direct acting 

 engines, there seemed to be some ambiguity as to the power 

 required to put the weight of the heavy beam in motion ; the 

 only loss of power arising from the weight of the beam would be 

 the extra friction caused by the increased pressure on the rubbing 

 surface of the beam gudgeons, for all the extra power required for 

 putting the heavier mass into motion in the first portion of the 

 stroke was returned again by dragging the beam forward in the 

 latter portion of the stroke whilst the propelling power of the 

 steam was diminishing. 



A force proportionate to the inertia of the beam would be 

 required to set it first in motion ; but if it were supposed to be 

 placed between two springs resisting its motion equally on each 

 side of the central position, then the force originally imparted to 

 the beam in starting it into motion would be spent in the com- 

 pression of the opposite spring, and would be all returned again 

 by the recoil of the spring if of perfect elasticity ; and the beam 

 would be propelled back to its first position with the same velocity 

 as before, causing the similar compression and recoil of the other 

 spring. The beam would thus continue to oscillate backwards 

 and forwards like a pendulum, however heavy it might be, without 

 any further power being required beyond what was necessary to 

 overcome the friction of the bearings. 



* Excerpt Minutes of Proceedings of the Institution of Mechanical Engineers. 

 1859, p. 40. 



