40 AGRICULTURAL ENGINES. 



succeeded with your portable steam-engine, and am persuaded 

 they will be more and more adopted. I have shown your ac- 

 count of your thrashing by steam, and Sir John Sinclair and 



Mr. very highly approve it. Sir John Sinclair wished the 



communication had been made to the Board of Agriculture. 

 Sir John wished me to transmit you the enclosed on coals 



moved by steam whether you had a plan of this sort, 



as they would be very serviceable in passing the friths in Scot- 

 land. He seems to think you ought to advertise your steam- 

 engines for thrashing ; indeed, I think so too. 



" By the enclosed letter, Sir John Sinclair wishes you to send 

 him an account of your improved steam-engines. You will be 

 careful in drawing up your letter to Sir John, because it will 

 probably be read to the Board of Agriculture, and perhaps in- 

 serted in their publication. You will begin by acknowledging 

 his letter, of date respecting the American pas- 

 sage boat and your improved small steam-engine. 



You will give him an account of the saving you have effected at 

 Dolcoath, and a certificate of the same by the mining captains ; 

 the engine for thrashing you built for me, and the work it did, 

 and the coals it consumed ; the expense of the steam-engines? 

 and the uses they may be applied to. 



" I remain, dear Sir, 



" Yours most obediently, 



" C. HAWKINS." 



In 1812 Trevithick advertised the use and sale of 

 steam-engines, weighing 15 cwt., costing 63/., for 

 thrashing, grinding, sawing, or other home work ; and 

 also a more powerful engine for the steam-plough, or 

 the harrow and spade machine for 105/., to travel from 

 farm to farm. He wrote to Sir John. Sinclair i 1 



" I received from Sir Charles Hawkins a copy of Dr. Logan's 

 letter to you, also a note from you to Sir Charles Hawkins, 

 both respecting the driving boats by steam ; respecting the 



1 See Trevithick's letter, 26th March, 1812, chap. xv. 



