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THE NEW CALIFORNIAN STAMPS AT DOLCOATH MINE. 

 Bt JOSIAH THOMAS, Esq., J.P. 



The ''Cornish Stamps," which is almost universally used 

 throughout the County for stamping tin stuff, is known as a 

 " gravitation stamps," the work done depending mainly on the 

 weight of the heads and the height they are lifted. Some 

 improvements have been made in this type of stamps during my 

 remembrance. Iron lifters have generally been substituted for 

 wooden ones, and the heads have been made heavier than 

 formerly, but the same cumbersome cast iron axles and the same 

 form of heads are still used. The great drawbacks to this kind 

 of stamps are the enormous dead weight of the axles and cams 

 (amounting in a large stamps to 30 or 40 tons), and the square 

 heads which, being fed from behind, wear away in the back part 

 faster than in the front, and thus become much less effective. 



The New Californian Stamps, recently erected at Dolcoath 

 Mine, is also a gravitation stamps, but is constructed on a 

 different principle. The heads and lifters are round, and are 

 made to revolve — the lifters 3 inches in diameter working in 

 teak wood guides. The heads are fitted in the bottom with cast 

 iron shoes, of about l^^-cwt. each, which take all the wear, so 

 that there is practically no wear in the heads themselves. There 

 are at present 40 heads at work, but the steam engine is of 

 sufficient power to drive an additional 40 heads. There are 8 

 iron coffers with 5 heads in each, arranged in 4 batteries of 10 

 heads each, driven off the main shaft by a separate leather belt 

 to each battery. Cams lifting the heads twice to a round are 

 fixed on a cam shaft 5 inches in diameter. There is a separate 

 finger or " jack up " provided for each lifter, so that each coffer 

 can be quickly stopped for repairs or renewals when required 

 without interfering with the working of the remaining stamps. 

 The falling weight of each head is 800-lbs., set to drop 9 inches, 

 and run at a speed of 80 drops per minute. The mesh of grate 

 used is No. 37, having 132 holes to a square inch. 



