Blasting of Rocks— Danger and Remedies. l-3'7 



?used, it is still much less than is required to charge in the okl method, 

 as described by Mr. Catlin, Should this method, on further tria!, 

 be found to be sure and effectual, it will afford as full a remedy, as 

 can perhaps be expected, for the hitherto hazardous nature of the 

 employment. With the most respectful consideration, 



I am. Sir, your friend and servant, 



Eli W. Blake. 



III. Letter of the Editor to Dr, Catlin, 



Dear Sir — ^It is perhaps hardly necessary to add any thing, after 

 the able and clear instructions, given by Mr. Blake. But as people 

 are more prone to go on as they have been accustomed to do, than 

 to adopt new modes, although improved ones, it may not be amiss 

 to say, that Mr. Blake's method appears to me, to embrace all the 

 desiderata, both theoretical and practical, which the case requires. 



1 . You are aware that the explosion of gunpoioder, arises from 

 ike instantaneous production of a vast quantity of gases, which be- 

 ing also expanded by the red heat, cannot be confined, and of course, 

 when not permitted to escape, rend their enclosure. With a given 

 quantity of powder the tendency of the gases to rend the enclosure, 

 is increased, in proportion as we increase the resistance which we 

 present, tending to prevent their escape ; and we modify this re- 

 sistance, to suit our views, in different cases. In a gun, we add 

 a wad, not only to retain the powder, but to cause its more instanta- 

 neous combustion, and to confine the action of the gases in that di- 

 rection, to the bullet ; it is not our object to do more, and if our charge 

 is too great ; or the wadding is rammed down too hard ; or there is 

 upon it, too great a load of metal, the reaction is so violent, as to burst 

 the piece. This is a rare accident, considering how many discharges 

 are made by careless people : and we are scarcely aware how much 

 the force of an explosion is increased by even slight resistance. — ■ 

 A train oF gunpowder laid on a board, burns, as we know, with so 

 little rapidity, that w^e easily v/alk or run faster than it goes ; but, if 

 another board be laid over the train, and w^eights placed upon it, al- 

 though still open at the sides, the powder then burns with amazing 

 rapidity. Powder merely flashes in the pan of a musket, but the 

 same powder placed in a quill, burns vehemently ; still more, fulmi- 

 nating mercury, virhich also flashes, (although with intense brightness,) 

 when fired in a heap, explodes with great -vaolence, in a quill. 



Vol. XVIL— No. 1. 18 



