2fo Befcription of the different Methods 



Then place in the hole a tube of tin plate clofed at the 

 lower extremity. The exterior diameter of this tube is of 

 fuch a fize that, when introduced into the bore, it may fill 

 it ; and its length muft be fuch as that it (hall rife fome cen- 

 timetres above the furface of the water. 



Then fend down to the bottom of this tube the cartridge 

 filled with powder ; introduce the priming rod, and ram 

 round it clay or plafter according to the ufual procefs, and 

 only to the height corresponding to the fummit of the hole. 



In the laft place, draw the priming rod and introduce the 

 train, and let fire to it with all the necefiary precautions, 

 that the workmen may be dickered from danger at the time 

 of explofion. • 



Obfervation. 



6th, This method has been often employed with advan- 

 tage in feveral mines of the republic : it may ferve either for 

 deepening wells, or making other excavations, when the 

 means uied for keeping the ground and bottom of wells 

 conftantly dry are infufficient. 



II. Method propofed for blowing up Rocks fome Decimetres 

 below Water, 



7th, When the ground or rock to be blown up is covered 

 only by fome decimetres of water, the miner can fee the rock 

 which he bores, and the hole to be loaded, with as much 

 cafe as if there were no water, and can work with the fame 

 facility. In this cafe, to fave expenfe, the tube of tin plate 

 may be omitted, and a cartridge of pitched cloth, fuch as that 

 employed in ground through wdiich the water oozes in every 

 part, may be employed, adapting to it a rod of hollow wood * 

 cleftined to contain the train that conveys the fire to the 

 powder. The diameter of the aperture of this rod may be 

 only a few millimetres, and its length muft exceed the upper 

 level by fome centimetres. 



8th, If this method be adopted, firft conftrucl: a cylindric 

 cartridge of cloth or pafteboard, and fill it with gunpowder; 

 infert mto it the rod, which muft defcend to the middle of 

 the length of the cartridge without approaching the interior 

 furface of the wrapper ; pinch clofely the upper part of the 

 cartridge around the rod, and cover the cartridge and whole 

 rod uith pitch or fome kind of varnifh f. Then fend down 

 the cartridge furnifhed with its rod into the hole of the rock, 



• This rod might be made of the elder or honeyfuckle. 

 f A folution of Spanifli wax in alcohol is attended with the advantage 

 af drying ipeedily, and of remaining water- proof for a long time. 



and 



