president's address. 175 



Rotative Atmospheric Engines. It appears that attempts were 

 made as early as 1768 to produce a rotative motion from a 

 Newcomen eng'ine ; but it was not till about 1 780 that it was 

 successfully accomplished by the use of the crank. It does not 

 appear that any attempt was made, before Watt's separate con- 

 denser was invented, to reduce the cooling effect of the injection 

 water on the cylinder by effecting the condensation in a small 

 vessel attached to the cylinder. It is however evident that, after 

 Watt's patent, Newcomen engines were made with separate con- 

 densers without air pumps, the air being discharged through a 

 sniffing valve. The condensers were known as " pickle-pots." 



I think it may be of interest to give here a copy of the 

 Table of Engine work, as now exhibited at South Kensington 

 Museum, shewing the number of lbs. raised one foot per hour 

 by the consumption of i 12 lbs. of coal. 



1718 Newcomen 4,300, 000 



1767 Newcomen, Smeaton & Beighton 7,400,000 



I 774 Smeaton 12,300,000 



1774 Watt 21,000,000 



1778 Watt with expansion 31,000,000 



1800 Watt do. 66,000,000 



1842 The Cornish Engine 100,000,000 



1883 Water- works Engine ] 20,000,000 



To the above may be added : — 



1774 *Savery, according to Smeaton's ) ., ,,„„ ,^,.„ 

 , -^n' ^. ° ;■ /, 000, 000 



calculations ) ' 



1904 The old Farme Newcomen )..„„„ „.„ 

 engine as now working j ' ' 



In order to conlirm my statement how much the world owes 

 to Cornwall for the introduction and the perfection of the steam, 

 engine, I think I must make special reference to one or two men 

 of great ingenuity who worked in Cornwall. 



Joseph Hornblower the elder came to Cornwall in 1725 to 

 erect a Newcomen engine at Wheal Rose, near Redruth, He 

 erected various other engines in Cornwall and settled in Salem, 

 Chacewater (though it is stated he died in Bristol). His son, 



* Horse power as applied to the steam engine was invented by Savery ; it is 

 33,000 lbs. raised one foot per minute or almost exactly 2,000,000 lbs. raised i ft. per 

 hour. 



