24 THE HISTORY OF [SECT. i. 



He further states, that any load will do if the parts be properly proportioned ; 

 but, from a long course of very laborious experiments, he had fixed his scale 

 near upon, but somewhat under, eight pounds to the inch, including raising 

 the injection water. 



The labours of Smeaton show the imperfect state of mechanical science, as 

 applied to practice, in a remarkable degree. He actually designed an engine, to be 

 erected at Long Benton, to raise water for turning a water wheel to draw coals 

 from a pit; 1 and in 1781 proposed one of Boulton and Watt's engines to be 

 erected for raising water for driving a corn mill ; 2 using such arguments as these 

 in support of his opinion. " It is to be apprehended that no motion communicated 

 from the reciprocating beam of an engine can ever act with perfect equality and 

 steadiness in producing a circular motion like the regular efflux of water in turning 

 a water wheel ; and much of the good effect of a water mill is well known to 

 depend upon the motion communicated to the millstones being perfectly equable 

 and smooth : the least tremor or agitation takes off from the complete performance. 

 Secondly, all the engines he had seen were liable to stoppages, and so suddenly, 

 that in making a single stroke the machine is capable of passing from nearly its 

 full power and motion to rest ; for whenever the steam gets lowered in its heat 

 below a certain degree, for want of renewing of the fire in due time or otherwise, 

 the engine is then incapable of performing its functions. Jn the raising of water, 

 (a business for which the fire engine seems peculiarly adapted,) the stoppage of the 

 engine is of no other ill consequence than the loss of so much time ; but in the 

 motion of millstones grinding corn, such stoppages would have had a particularly 

 bad effect." 



It was certainly not a gratifying circumstance to Smeaton to find that his tedious 

 inquiries had been rendered nearly useless by a new mode of operation ; to find 

 that his cautious system of analysis was not in all cases the best mode of rendering 

 the powers of nature useful to man. Yet if it were his labours on the steam engine 

 alone on which his fame rested, there would be sufficient to command our esteem 

 and respect : its further improvements, its close cylinder, its double action, un- 

 doubtedly owed much of their perfection to the use of the modes of construction 

 applied by Smeaton to the air pump. 



g 1766. JOHN BLAKEY. 



25. Though there are so many circumstances in the mode of action which 

 reduce the effect of an engine of Savery's construction, these defects seem only to 



1 Smeaton's Reports, vol. ii. p. 435. * Reports, vol. ii. p. 378. 



