310 Sleam^ Engines at Consolidated Mines. 



have l)cen before constiuctcd, and of course every part is of a di- 

 niensioii for which tlicre is no precedent, yet each has from the 

 first performed its office aright, and the combination is so perfect 

 that the motions are equable, and free from jar or concussion. 

 The engines have worked repeatedly for days at the rate of twelve 

 and thirteen strokes a minute, and the whole has gone as smoothly 

 as if a flywheel regulated the impulse. 



The effect of the first of these engines, or, as it is called in 

 Cornwall, the duty, has been regularly calculated by the person 

 appointed for that purpose, and has been published in the monthly 

 report. 



It was found to have consumed about 3,800 bushels of coal in 

 3.1 days, or 1 11 bushels per day ; and the effect had been that of 

 raising 38,500,000 lbs. of water by each bushel of coal, which is 

 rather more than was done in the same period by any engine of 

 similar construction. 



It may be worth mentioning the weights of some of the prin- 

 cipal parts of one of these large machines. The cylinder, ex- 

 clusive of the cover and bottom, weighs about 12t tons, in one 

 piece; it is surrounded by a case of still greater dimensions. The 

 beam with its gudgeon weighs nearly 25 tons. 



The pump rods in the shaft are the largest mast timber that 

 could be procured, and are 16 inches square to a considerable 

 depth in the shaft: when the whole are attached, they will weigli, 

 with the iron plates which connect them togetiier, nearly 40 tons. 



When it is considered that to this latter weight is to be added 

 that of the column of water, and one half of the beam, we shall 

 find nearly 100 tons on one side the centre, and of course a cor- 

 responding pressure on the other side to counterpoise it ; so that 

 there is suspended on the gudgeon, and moving freely upon it, 

 nearly 200 tons. 



The piston frequently passes through 240 feet every miimte, 

 and gives a corresponding velocity of motion to this immense 

 mass of matter, which is yet regulated with a precision that is 

 astonishing, and which acts without concussion, and without dis- 

 turbance to the various parts of the machine. 



There are many most ingenious improvements in the construc- 

 tion, and the arangcment is simple and complete. The whole 

 reflects great credit on the skill and ability of Mr. Woolf, to 

 whom Cornwall has before been indebted for the introduction of 

 some of the most important improvements in steam engines that 

 have benefited the mines in later years. 



The works at the Consolidated Mines were only commenced 

 in January 1819, and it is probable that in a few weeks the wa- 

 ter will be all pumped out; so that this, with the cxteubive erec- 

 tions 



