THE CONQUEST OF NATURE 



inventor, was enabled to make the change, gradually, 

 but in the end effectively. 



HIGH-PRESSURE STEAM 



As regards the use of steam under high pressure, 

 somewhat the same remarks apply, so far as concerns 

 the conservatism of mankind, and the influence which a 

 great mind exerts upon its generation. Just why Watt 

 should have conceived an antagonism to the idea of 

 high-pressure steam is not altogether clear. It has been 

 suggested, indeed, that this might have been due to the 

 fact that a predecessor of Watt had invented a high- 

 pressure engine which did not use the principle of con- 

 densation, but exhausted the steam into open space. 

 As early as 1725, indeed, Leupold in his Theatrum 

 Machinarum, had described such a non-condensing 

 engine, which, had it been made practically useful, 

 would have required a high pressure of steam. Partly 

 through the influence of this work, perhaps, there came 

 to be an association between the words high pressure 

 and non-condensing, so that these terms are considered 

 to be virtually synonymous; and since Watt's great 

 contribution consisted of an application of the idea of 

 condensation, he was perhaps rendered antagonistic to 

 the idea of high pressure, through this psychological 

 suggestion. In any event, the antagonism unquestion- 

 ably existed in his mind; though it has often enough 

 been pointed out that this seems the more curious since 

 high-pressure steam would so much better have facili- 

 tated the application of that other famous idea of 

 Watt, the use of the expansive property of steam. 



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