[ 97 ] 



XXir. On Blasting Rocks, and Tamping. By John" 

 Taylor, Esq, 



To Mi\ TillocL 



SIR, 



A LETTER from an engineer of celebrity to Mr. Nicholson, 

 and published in the ninth volume of his Journal, introduced 

 to the public some time ago an account of the use of sand 

 in blasting rocks or other hard substances : a letter from 

 another gentleman, published in your Magazine soon after, 

 continued the subject, and mentioned other modes of con- 

 fining the gunpowder employed for this purpose ; and we 

 have been lately informed of the result of experiments made 

 in France upon what Mr. Nicholson calls Mr. Jessop*s me^ 

 thod of blasting rocks with sand, by a notice published in 

 the Philosophical Journal of July last. 



As the process has long been known, however, in this 

 neighbourhood, and the constant experience of the work- 

 men in the mines and quarries agrees pretty nearly with the 

 French report, it may not be useless to detail the instances 

 in which it may be advantageously employed, and to point 

 out the cases where it is not likely to be effectual ; and in 

 mines the latter are more numerous than the Ibrmrr. 



As another substance has been lately introduced into use 

 here, which possesses advantages occasionally overall others, 

 it will likewise give me pleasure to fnake it more generally 

 ;icnown, especially as this is an operation on the easy execu- 

 tion of which often depends the safety of the lives of 

 the persons conducting it. The new process I allude to, is 

 that of closing the hole, upon the proper charge of gunpow- 

 der, with clay wrought to rather a soft consistency, and 

 rammed- in in suOicient quantity, which, where the resis- 

 tance is not too great, possesses the following advantage^. 

 It may be applied to holes bored in all directions ; may be 

 perforated for the fuse w iilmul danger,' and is^peculiarly adapt- 

 ed for rock in which gunpowder is liable to be rapidly in- 

 jured by water. Sand can only be used where the rock is 

 bored perpendicularly or nearly so ; and in mines but few 

 holes of this description occur> the effect of a given <^uan- 



Vol. 30. No, 118. March 1808, G ti^r 



