AND SURFACE CONDENSER. 317 



with extensive fire-sides, both to heat water and steam, and yet 

 be very light. 



" It appears that this engine, when working without the 

 heated flues round the cylinder and pipes, evaporated 20,000 

 gallons of water into steam, in twenty-four hours, more than 

 when the flues were heated, and the increase of condensing 

 water was in the same proportion. It is so unaccountable to 

 me that I shall not be satisfied until L prove the fact, the result 

 of which I will inform you, and shall be very glad to receive 

 your remarks on the foregoing statement. 



" The first engine that will be finished here for Holland will 

 be a 36-inch cylinder, and a 36-inch water-pump, to lift water 

 about 8 feet high ; on the crank-shaft there is a rag-head of 

 8 feet diameter, going 8 feet per second, with balls of 3 feet 

 diameter passing through the water-pump, which will lift about 

 100 tons of water per minute. It is in a boat of iron, 14 feet 

 wide, 25 feet long, 6 feet high, so as to be portable, and pass 

 from one spot to another, without loss of time. It will drain 

 18 inches deep of water (the annual produce on the surface of 

 each acre of land) in about twenty minutes for the drainage of 

 each acre, with one bushel or sixpennyworth of coal per year. 

 The engine is high pressure and condensing. 



" I remain, Sir, 



" Your very humble servant, 



"KicHARD TREVITHICK. 



" P.S. Woolf is making an apparatus to throw back from the 

 bottom of the cylinder on to the top of the piston a fluid metal 

 every stroke. He says he proved by an indicator that he raised 

 18,000 inches of steam from 1 inch of water, of 11 Ibs. to the 

 inch pressure on a vacuum, and that the reason why this 

 engine did not do 300 millions, was because the steam passed 

 by the sides of the piston. That an engine at the Consolidated 

 Mines working 10 feet 2 inch stroke, going |ths expansive, 

 beginning with steam of 20 Ibs. to the inch above the atmo- 

 sphere, and ending with 11 Ibs. on a vacuum. I doubt this state- 

 ment ; however, there is some hidden theory as yet, because 



