AGRICULTUKAL ENGINES. 45 



before, the same kind of engine had been made to 

 work pumps, wind coal from shafts, drive rolling mills, 

 tilt hammers, and steamboats, and convey material from 

 place to place ; and why should not his promise to the 

 farmer be also made good with his increased know- 

 ledge derived from eight years of active experience ? 

 Eeceiving small encouragement in England, he applied 

 to sugar-cane planters to give his engines a trial in 

 the West Indies. 



[Rough draft.] 



" SIR CHARLES HAWKINS, Bart., " CAMBORNE, 1st May, 1812. 



" Sir, I have your favour of the 27th April, respecting 

 a steam-engine for your friend for the West Indies, of the 

 power of ten mules employed at one time. This power we cal- 

 culate equal to forty mules every twenty-four hours, as six hours' 

 hard labour is sufficient for one mule for one day. 



" The expense of an engine of this power complete delivered in 

 London would be 200Z. The consumption of coals about 84 Ibs., 

 or one bushel, to equal the labour of three mules, or from 13 

 to 14 bushels of coal every twenty-four hours to perform 

 the full work of forty mules (or in proportion for a lesser num- 

 ber), with a waste of about 15 gallons of water per hour, unless 

 a reservoir was made to receive the steam, and then to work 

 the same water over again. 



" Where water is scarce, nearly the whole may be saved. 



" You remarked that the rope might slip round the notch 

 in the wheel ; but to prevent any risk of that kind, I apply a 

 small chain instead of the rope, which works the same as a 

 chain on the barrel of a common thirty-hour clock. 



" The speed of the periphery of the fly-wheel is about eight 

 miles per hour, which I think is nearly double the speed of 

 the mules when at work in the mill. This would reduce the 

 size of the part which carries the chain on the cattle mill to 

 half the diameter of the present walk' of the cattle, which 

 might be done without altering or interfering with the present 

 cattle mills, and might, if required, either work separately or 



