100 POLE STEAM-ENGINE. 



" The engine worked 9 strokes per minute, with 2 bushels 

 of coal per hour for the whole time, 10-feet stroke. There were 

 two pump-lifts of 14J-inch bucket, making 43 fathoms, and 26 

 fathoms of 6 -inch for house- water. 



The steam was from 100 to 120 Ibs. to the inch. The valve 

 open while the plunger-pole ascended 20 inches, then went the 

 remainder of the 10-feet stroke expansive. 



" It went exceedingly smooth and regular. Some time since, 

 by way of trying the power of the engine, we disengaged the 

 balance-bob. The engine worked twenty strokes per minute, with 

 17 tons of rods, &c., and drew 14^-inch. bucket 23J fathoms, 

 and a 6-inch bucket 26 fathoms, 10-feet stroke, twenty strokes 

 per minute. 



" This was about 45,000 Ibs. weight, with the speed of 200 

 feet per minute, which makes the duty performed more than 

 the power of three 72-inch cylinders, single, of Boulton and 

 Watt, say of 8-feet stroke, 10 Ibs. to the inch, nine strokes 

 per minute, which is more than these engines will perform. I 

 have all the orders for every engine now required in the 

 country, which is not to be wondered at, for one-tenth part of 

 the expense in the erection will do, and the duty is not less 

 than three times as much as other engines. This will be proved 

 before we get to the bottoms 



" The engine now works at about two-fifths of the load which 

 she will have when a"t the bottom. When the next lift is in fork 

 I will write to you again. 



" I am, Sir, your humble servant, 



" EICHAED TEEVITHICK." 



Independent examiners reported that the Herland 

 pole-engine did forty-eight millions of duty, under 

 various pressures of steam, up to 120 Ibs. to the inc 

 working five-sixths of the stroke expansively, with a 

 speed of twenty strokes a minute, or double the speed 

 of the Watt engine; and the importance of those facts 

 deserves the scrutiny and close study of youthful engi- 

 neers. A small cheap engine, of 33-inch cylinder, 



