or other Articles from Mines. 199 



even be preferred. It is certainly more reasonable to sup- 

 pose that this will be the case from the superiority -which 

 iron holds in point of strength of materials, than that ropes 

 even should have been known, (at least in the mines,) had 

 the new method of working chains been in use prior to the 

 introduction of hemp. 



By excusing the liberty which I am now taking, you will 

 oblige. Sir, your obedient servant, 



GiLBEBT Gilpin, 



Old Park Iron Works, 

 March 7, 1807. 



To C. Taylor, M.D. Sec. 



Reference to the Engraving of Mr. Gilhert Gilpin's im- 

 proved Machine for raising Coal, Ore, ^c. Plate VT. 

 Fig. 1, 2, 3, 4. 

 Fig. 1. a. A crank to which the connecting rod is fixed to 



attach the machine to the steam-engine which works it. 

 I. A wheel of 13 teeth, wedged upon the same shaft with 



the crank, and which works into the wheel d. 



c. A fly wheel 1 1 feet in diameter, wedged upon the same 

 shaft as the wheel h. 



d. A wheel of 64 teeth wedged upon the same shaft as 

 the barrel, into which the wheel h works. 



e. A wooden barrel, formed of two frustums of cones 

 united base to base, and folded spirally with wrought iron 

 tire, which keeps the links of the chains at right angles with 

 each other, and with the grooves in the pulleys. 



ff. The reeling- post and its lever, for disengaging the 

 barrel from the steam-engine, when the men are to be let 

 dovvn into the pit by means of the break. 



gg. A break wheel, break and lever, for regulating the 

 velocity of the barrel when disengaged from the steam en- 

 gine, and in the act of lowering the miners into the pit. 



Ilk. The frame on which the machine is erected. 



ii. Fig. 2. The pit-frame, for supporting the pulleys. 



k. The pit represented by a circle, part of which is shown 

 open, and part by dotted lines. 



//. Two grooved pulleys, over which the chains, extending 

 2 considerable length from the barrel a, work in parallel lines. 



N 4 in. The 



