‘tga: Blasting of Rocks—Danger and Remedies. 
2. Our object, then, is to repress the force to such a degree as to 
accomplish our purpose ; which, in fire arms, is to give velocity to a 
ball; but, in the case before us, it is to rend asunder the surround- 
ing matter. In the old method of blasting rocks, this was most ef- 
fectually accomplished, by ramming -down pounded brick upon the 
wadding. This closed the hole so thoroughly, that commonly, the 
brick would remain undisturbed by the explosion, which of course, 
spent itself upon the rock, and tore it asunder. 
In blasting logs, also, the same object was attained, by driving a 
wooden pin into the hole above the wadding; and here again the 
pin often remained in its place, after the explosion which burst the 
log. 
3. But, in blasting rocks, painful experience has shown, that great 
danger of premature explosion is encountered, whenever firm sub- — 
stances are made use of to close the canal above the powder ; and 
multitudes have been killed outright, or dreadfully mutilated by these 
casualities. 
4. The ingenious remedy, first proposed by the French, and em- 
ployed, if I mistake not, by the Engineers of Napoleon in construct- 
ing his famous roads through the Alps, removed the danger of explo- 
sion, but was not in every case effectual.—Mr. Blake has, however, 
given us the rule, by which the desired effect may be rendered cer- 
tain, and there can be no hesitation in applying it, as is indicated by 
him, when the hole is bored to a certain depth. But, as the suc- 
cess is not universal, and the reason and remedy were unknown to 
the workmen, this method seems not to have been generally adopted 
in this country. 
5. Thé method of Mr. Blake combines all the advantages of the 
French mode, with another important one, which is peculiar to his 
contrivance.—It is equally safe with the French method, (both are 
perfectly safe,) and Mr. Blake’s supplies the only deficiency in the 
French mode. The latter was effectual, evidently, because the re- 
sistance afforded by the column of sand, when of a certain depth, 
was sufficient to produce the necessary reaction upon the rock ; per- 
haps the movement which would be given to the sand, by the first 
expansive lift, when the powder was kindled, would even facilitate its 
thorough and sudden inflammation, by giving room to the flame to 
dart at once, into, and among the grains; while the pressure would 
‘force the flame to pervade, instantaneously, the whole magazine. 
