VARIOUS INYKNTlnNS. 25 



holes of 2J inches in diameter 4 feet deep per hour. Now 

 suppose the engine to stand on the top of the cliff, or on any 

 level surface, and a row of holes bored, 4 feet in from the edge 

 of the cliff, 4 feet deep, and about 12 inches from hole to hole 

 for the width of the piece to be brought down at one time, and 

 wedges driven into the holes to split the rock in the same way 

 as they cleave moorstone, only instead of holes 4 inches deep, 

 which will cleave a moorstone rock 10 feet deep when the holes 

 are 14 or 15 inches apart, the holes in limestone must go as 

 deep as you intend to cleave out each stope, otherwise the rock 

 will cleave in an oblique direction, because detached moorstone 

 rocks have nothing to hold them at the bottom, and split down 

 the whole depth of the rock. In carrying down a large piece of 

 solid ground the bottom will always be fast, therefore unless it 

 is wedged hard at the bottom of the hole the stope cannot be 

 carried down square. In a hole 2J inches 

 diameter and 4 feet deep put in two 



pieces of iron, one on each side of the fl J JL 



hole, having a rounded back, then put a 

 wedge between the two pieces, which 

 might be made thus, if required to wedge 

 tighter at the bottom of the hole than at 

 the top. 



" If this plan answers, the whole of the stones would be fit for 

 service, even for building, and would all be nearly of the same 

 size and figure. Each piece would be easily removed from the 

 spot by an engine on a carriage working a crane, which would 

 place them into the ship's hold at once. It would all stand on 

 a plain surface, and might be had in one, two, three, or four tons 

 in a stone, as might best suit the purpose, which would make 

 the work from beginning to end one uniform piece. Steam 

 machinery would accomplish more than nine-tenths of all the 

 work, besides saving the expense of all the powder. I find that 

 limestone will split much easier than moorstone, and I think 

 that a very great saving in expense and time may be made if 

 the plan is adopted. 



" Please to think of these hints and write me when and where 

 I may see you to consult on the best method of making the 



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