I 



BLASTING OF llOCiCS* 241 



threads it may be detached from the paper, and fubje6led to 

 ftny future inveftigation. 



I am. Sir, 

 ^ Tour's, &c. 



Ktnda],Jutr^t, THOIVtAS HARRI^Oltf.'; 



'' 1805. 



P. S. I cannot refrain from calling to the recolledion of Account of the 

 your readers a valuable paper in the 9lh Vol. p. 230, of yOur catbn'of'the^^"'' 

 Journal, recommending the ufe of fand in the blading of rocks, method of blaft- 

 The efFeas there related of this fimple ascent, I confefs did *"S rocks indl- 



n-n 1 I-T1 1 r cated in this 



altoniln me more than any thmg 1 ever read : ana as very le* journal by W, 

 rious and even fatal accidents have happened by the method of Jeflop* Ef^« j 

 ramming blafts with ftone in the limeftone and Hate quarries 

 in this neighbourhood, I was determined to repeat the experi- 

 ment the firft opportunity, and thus fhew its effefts to the men 

 who work in thofe places. Accordingly no long period 

 elapfed before I had occaiion to be fn the neighbourhood of 

 the fiate quarries in Longlliddale, about ten miles from Ken- 

 dal ; when I went to one of thofe quarries, taking with me 

 a bag of fmall fand, confifting of powdered freeflone ufed 

 in this country to fcour pans with, and ftrew upon the ftone 

 floors. I mentioned my bufinefs to one of the workmen who 

 was then engaged in boring a hole 24 inches deep and about 

 an inch diameter in a flate rock ; the ftratum was about 27 

 inches thick, and reclined from the perpendicular about 20 

 degrees ; and this being the firft blaft, it was confcquently 

 iirmly furrounded and fixed in on all tides by folid rock : The 

 part that he wanted to throw out by the blaft was fuppofed to 

 be five ton weight : The diredion of the hole which he was 

 boring was perpendicular to the flratum, and therefore ele- 

 vated above the horizon about 20 degrees. He fmiled at 

 my propofal, but faid he would try the experiment to fatisfy 

 me, provided I would pay for the powder if it failed ; but he 

 feemed to think that I had a very poor idea of blafting, to 

 believe that a little light fand would aniwer the purpofe of the 

 laborious and dangerous procefs of ramming which he had been 

 accuftomed to ufe. However, he charged his blaft with pow- 

 der in the manner he had been ufed to do ; i. e, into thi* hole 

 Vol. XL— August, 1803. R of' 



