THE APPLICATIONS OF EXPLOSIVES. 



451 



Hollow Dynamite Caut- 

 KiDGE ; Elevation. 



Avliicli is often fifteen hundred feet or more in depth. A per- 

 forated weight is then strung on the wire, and when the tor- 

 pedo is in place the weight is allowed 

 to fall, strike the cap, and explode the 

 charge. 



Dynamite has been used to knock out 

 the blocking from the ways when launch- 

 ing ships. Fired on an iron plate placed 

 on the top of a pile and covered with a 

 tamping of earth or clay, it has success- 

 fully and economically replaced the pile 

 driver. It has been found efficient in ex- 

 cavating holes in which to plant telegraph 

 and telephone poles; in driving water out 

 of quicksands in which foundations are to 

 be laid or shafts to be driven; in slaugh- 

 tering cattle; in breaking down ice dams 

 to prevent inundations; in blowing up 

 buildings to prevent the spread of confla- 

 grations ; in razing unsafe walls of burned 

 buildings; in destroying wrecks which en- 

 danger navigation, and even in freeing vessels which arc hard 

 aground on shoals. 



An especially notable instance was in the blasting out of the 

 debris in the river at Johnstown after the frightful flood that oc- 

 curred there, which formed an enormous dam above the bridge 

 and threatened its existence, and which was successfully and expe- 

 ditiously removed by blasting 

 after all other means had 

 been tried in vain. 



In fact, the amount of ex- 

 plosives consumed in the in- 

 dustries is so great that the 

 quantity employed for mili- 

 tary purposes sinks into insig- 

 nificance. Yet we have failed 

 to refer to those industries 

 — quarrying and mining, and 

 the engineering operations — 

 in which they are most ex- 

 tensively and commonly used, 

 being employed so largely in mining alone that it is an almost daily 

 occurrence for blasts containing twenty, thirty, and even fifty 

 thousand pounds of explosives to be used in a single charge; and 



Hollow DY^■AMITE Cartridge. 

 View from below. 



