18 VARIOUS INVENTIONS. 



Mr. Praed helped forward the screw-propeller, or that 

 Sir John Sinclair gave direct help, though he probably 

 made known the high-pressure steam-engine to the 

 marine experimenters on the Clyde. 



[Rough draft.] 



" MR. KASTRICK, " CAMBOBNE, December 7th, 1812. 



" Sir, I have been waiting your answer to my last, and 

 especially that part respecting the West India engine, as I have 

 not nor could not answer their letter to me without first hearing 

 from you; therefore must beg you will be so good as to answer 

 me by return of post on that subject. If they get impatient 

 about the time, and refuse to take the engine, I have no doubt 

 the Plymouth people will take it and several others ; but I 

 very much wish to send one to the West Indies, as there is a 

 large field open there for engines of this kind. I have received 

 an order for a thrashing engine for Lord de Dunstanville, of 

 Tehidy; and as I wish those thrashing engines to be known 

 through the country, I intend to take one of the engines ordered 

 for Padstow and send it to Tehidy. One of the Padstow 

 farmers can wait until you make another for him. There- 

 fore I would thank you to send the first finished by ship from 

 Bristol for Portreath or Hayle. Send a drum with everything 

 complete, of which you are a better judge than I. Probably 

 about 3 feet in diameter and 3J feet long will be sufficient. 



" There must be a fly-wheel with a notch to carry the rope, 

 and also a small notch-wheel on the drum-axle. I think 6 J feet 

 diameter for the fly, and 9^ inches diameter for the small wheel, 

 will give speed enough to the drum. Mind to cast a lump, or 

 screw on a balance, of about 1 cwt., on one side of the fly-wheel. 

 There must be two stands on the boiler, and a crank-axle, or 

 otherwise a crank-pin, in the fly-wheel, whichever you please; 

 with a shaft 3 feet long with a carriage. 



"The engine is to stand in a room under the barn, about 

 7J feet high, 7 feet wide, and 14 feet long. The fly-wheel will 

 stand across the narrow way of the room. The rope will go up 

 through the floor, and the drum be shifted by a screw, hori- 



