i6o 



THE POPULAR SCIENCE MONTHLY 



The advantage of using powder and dynamite combined is thus ex- 

 plained. If dynamite alone were used, the breakage would be carried 



too far; the fragments could not be as conveniently loaded by cranes. 

 Tlie effect of powder would be to project the fragments too far, thus 

 damaging, it might be, the neighboring works. As regards the use of 



