22 



MARINE AND FISHERIES 



6-7 EDWARD VII., A. 1907 



INSTRUCTIONS. 



' Dynamite, when properly used, is perfectly safe, but like all compounds of nitro- 

 glycerine, must be handled with care and judgment. Although it will explode, if 

 j'oasted up to a high temperature, it bums quietly if set fire to. In order to cause the 

 explosion in practical use, therefore, it must be fired by. means of an ordinary 

 ' Detonator ' with fuse, or by ^ Electric Detonators ' with a battery. 



' For the former, cut ofi a piece of fuse to a proper length, straight across, shake 

 all the sawdust out of the detonator, and push the fuse into it gently, nearly as far 

 as it will go, and close the edges of the cap down on to the fuse. Then, if to be used 

 under water, cover edges of cap with soap, grease, tar, or a similar substance, to keep 

 charge inside of cap dry. 



• Now, with a small punch, like a pointed lead-pencil, make a hole through the 

 paper in the end of a cartridge of dynamite, as deep as the length of the detonator. 

 If cap has been properly fastened to the fuse, the punched-in eoges of the paper after 

 cap is inserted will prevent its being pulled out, in lowering into the drill hole. 



' CAUTIONS. 



'Dynamite freezes at 42° Fahrenheit, and when frozen it is almost impossible to 

 explode by cap, although it is more sensitive to rough handling. In cold weather, there- 

 fore, care should be taken to thaw it until it becomes soft. It is dangerous to do this 

 before a fire. The proper method is to thaw the cartridge by means of a ' Thawing 

 Box,' such as we make and sell at cost, or to keep them in a warm room for several 

 hours before using, and to carry them to the work in a sack, wrapped up in a way to 

 prevent chilling before using, as dynamite at the freezing point, is more sensitive to 

 handling than at either a higher or lower temperature.' 



All the explosions at the seaside, and half of these at Kingston, were made by 

 means of a fuse and detonator. Some difficulty was at first experienced in pro- 

 ducing explosions at depths greater than ten or fifteen fathoms, but by closing the 

 detonators very firmly round the end of the fuse, covering the joint carefully with 

 common soap, and sinking the detopator well into the dynamite, we succeeded in 

 getting explosions in water as deep as 50 fathoms. When these precautions were not 

 taken, the increased pressure at the greater depths forced water into the caps and pre- 

 vented the fulminate of mercury from exploding. The difiiculty in getting explosions 

 along the Ottawa river was due to the fact that the fuse was not water tight. 



In Wiater from 18 to 25 feet deep, no sinker were attached to the cartridges ; but in 

 30 to 50 fathoms, stones or old pieces of iron were used to sink the dynamite as quickly 

 as possible. 



LAKE ONTARIO EXPERIMENTS. 



The first experiments were made in Kingston harbour, in water about 18 feet 

 deep. Two cartridges were used, the detonation striking our boat like a huge sledge 

 hammer. It stirred up a great deal of mud, and discoloured the water to a radius 

 of 6 or 8 feet, gradually widening to 30 or 40 feet. At first we thought that no fish 

 had been killed, but after waiting for about two minutes they began coming to the 

 surface, and inside of 15 or 20 minutes, 130 perch and 1 small black bass had been 

 lifted into the boat. About three dozen more were left floating; all were not dead; 

 some appeared to be only stunned. 



Post-mortem examination of a large number of these fish all showed similar 

 effects: great capillary haemorrhage from branches of the mesenteric arteries, conges- 

 tion of the liver and spleen, and invariably rupture of the swim bladder. Portions 

 of the intestines were usually forced dorsally into the cavity of the swim bladder, 

 where, of course, there was also much blood. In rare cases, there was rupture of the 

 venous sinuses feeding the auricles. 



