ENGINEERING BEFORE AND AFTER 

 THE WAR 



(Address of the president of the British Asso- 

 ciation for the Advancement of Science, Bourne- 

 mouth, 1919.) 



BY 



SIR CHARLES PARSONS 

 Developments Prior to the War 



James Watt. No excuse is necessary for entering 

 upon this theme, because this year (1919) marks the 

 hundredth anniversary of the death of James Watt, and 

 in reviewing the past, it appears that England has gained 

 her present proud position by her early enterprise and 

 by the success of the Watt steam engine, which enabled 

 her to become the first country to develop her resources 

 in coal, and led to the establishment of her great manu- 

 factures and her immense mercantile marine. 



The laws of steam which James Watt discovered are 

 simply these : That the latent heat is nearly constant for 

 different pressures within the ranges used in steam en- 

 gines, and that, consequently, the greater the steam pres- 

 sure and the greater the range of expansion the greater 



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