sometimes of advantage to make a chamber in the bottom of the hole by 

 first exploding a single cartridge in the bottom. This makes it possible 

 to get more of the main charge into the bottom and break the rock or 

 subsoil better. The explosion of the single cartridge may close the 

 hole a little, but it can easily be opened again with the auger or an iron 

 rod. The main charge must never be loaded immediately after chamber- 

 ing, but a half hour or more allowed for the bottom of the borehole to 

 cool off. This plan of chambering the bottom may also be followed 

 when water fills the bore holes. 



As the movement of water into this hole tends to carry dissolved 

 clay with it, which may eventually form an impervious coating over the 

 sand or gravel at the bottom and thus stop the drainage, it is advisable 

 to guard against this by filling the hole with coarse material immediately 

 after the blast. 



Have ready, 15 or 20 feet from the proposed hole, a pile of rubbish 

 such as pieces of corn stalks, cotton stalks, small pieces of stump wood 

 and a few forkfuls of hay or straw. Dump the rubbish into the blasted 

 hole, being careful not to clog it. Poke it down with a pole, then put the 

 hay or straw on top, filling in the last few feet with heavy chunks of earth. 

 Such a filled hole should establish permanent drainage. 



See pages 119 to 126 for proper methods of priming, charging, 

 tamping and firing. 



Road Building 



Road grading and ditching always take more or less digging, but 

 by using dynamite to loosen up the hard ground or shale, and to blast 

 out the rock, roads can be built quickly and at reduced- expense. 



To blast cuts not more than five feet deep through hard earth or 

 shale a bar should be driven down to grade and two or three 1 J4 x 8-inch 

 cartridges of Red Cross Extra Dynamite 40% exploded in the hole thus 

 made. Be sure to first tamp the charge properly. Holes should be 

 spaced five to eight feet apart. In this way the material to be removed 

 is not only broken up so that it can be shoveled very easily, but a good 

 portion of it is spread over the surrounding land and does not have to 

 be handled. 



Roads can be ditched with but little shoveling, by exploding about 

 half a cartridge of the same kind of dynamite in holes along the sides a 

 foot deep and two to three feet apart. 



If it is necessary to cut through rock, the holes should be drilled 

 closer together and charged heavier. See pages 119 to 126 for proper 

 methods of priming, charging, tamping and firing. 



151 



