430 THIRD REPORT — 1833, 



to time been made, and many of them even recently, must have 

 upon the production of some of the most useful metals. 



The number of steam-engines used in pumping water from 

 the mines in Cornwall in December 1832 was altogether 64. 



Some of these are of immense size and power : there are five 

 in the county, of which the diameter of the cylinder is 90 inches, 

 the pistons making a stroke of 10 feet. Four of these are at 

 the Consolidated mines, and the first constructed of this size 

 was planned and erected there by Mr. Woolf. The beam of 

 such an engine weighs 27 tons ; the pump rods are of mast 

 timber, 16 inches square, connected by iron strapping plates of 

 enormous weight. The column of water lifted, the rods and 

 beam, make up a weight of more than 100 tons, and this is kept 

 in motion at the rate of from 5 to 10 strokes per minute. 



The quantity of coal consumed in drawing water in the same 

 month in all the mines of Cornwall was 84,034 bushels, and the 

 quantity of water delivered, about 19,279 gallons per minute. 

 The weight of water actually poised by all these engines to 

 produce this effect amounts to about 1137 tons. 



From calculations carefully made in Mexico as to horse power 

 employed in draining mines, and deduced from a large scale of 

 operations, it is found that the performance is equal to 19,000 

 lbs. raised one foot high per minute for each horse. 



According to this rate, the coal consumed in Cornwall in a 

 month being 84,000 bushels, or 2800 per day, and taking the 

 duty of the engines at 55,000,000 pounds lifted 1 foot by each 

 bushel, which is very nearly the fact, it will be found that the 

 sixteenth part of a bushel does as much in raising water in 

 Cornwall as a horse does in Mexico, (working 3 hours out of 

 24,) and that thus the number of horses required to drain the 

 mines of Cornwall would be 44,800. 



On Naval Architecture. By Jeremiah Owen. 



A great deal has been done by mathematicians towards at- 

 tempting to establish a general theory of resistances, and con- 

 siderable expense has been incurred in conducting experiments, 

 some of which have been made on the Continent under the su- 

 perintendence of eminently scientific men. D'Alembert, Bos- 

 sut, Romme, and several others were employed at diflTerent 

 times in experiments of this nature. Don Juan in Spain, and 

 Chapman, the great Swedish naval architect, also made several 

 experiments on the same subject ; as did also the Society for 

 the improvement of Naval Architecture, which was established 

 in England some years ago, but which has now ceased to exist. 



These experiments have always been made upon models, the 



