196 Modes of obtaining Important Results [May, 



ed, to enable them to fill it. This mode it is evident would not answer well 

 for mixed metals, nor for metals difficult to fuse. The writer caste his 

 18 pr. brass naves in this mode, each man bringing his seer of molten 

 metal and pouring it out of earthen pans into the mould, kept surround- 

 ed by fire ; and he has no doubt but a brass pillar or statue of one 

 thousand seers in weight, might be cast in the same simple mode, by a 

 series of circles of a thousand pans and a thousand bellows surrounding 

 the fire-embedded mould, — not that we would adopt the pans, having a 

 knowledge of furnaces. 



3. — Strength of powder may be too great in mining. 

 A curious instance of simplicity on the part of natives, leading to use- 

 ful results, may be mentioned relative to the operation of blasting rocks : 

 the miners represented, that the government powder was not of the pro- 

 per kind ; that it blew out the tamping, without moving- the rock, or if 

 a very small quantity were put in, no effect was produced ; whereas the 

 common country powder was excellent ; with it they could make great 

 progress, but not so with the government powder. On going to the 

 spot, this was speedily remedied by mixing one handful of saw-dust with 

 each charge or handful of powder, so as to decrease the velocity of 

 ignition, and to admit of the expansive fluid acting on greater space. It 

 is believed that in mining operations generally it would be well to 

 mix saw-dust with the powder, when a sufficient chamber can be formed, 

 or to adopt some other mode of producing gradual expansion and re- 

 iterated concussion. 



4. — Mode of boucheing iron Guns, at a siege, or on emergency, without the aid of a 



regular drill lathe. 



Should the vent of an iron gun become so much enlarged as to be 

 unserviceable, before a siege has been brought to a favorable termina- 

 tion, a new vent may be applied on the spot, thus ; let the gun be with- 

 drawn from the battery, and be thrown down close to the nearest con- 

 venient tree ; and fixed on a block at the proper angle : insert a stout 

 trunk of another tree in the ground six feet apart from the standing 

 tree; pass a stout flat lever bar from one to the other, fixing one end to 

 the standing tree, but so as to move up and down on the smoothed front 

 of the other or inserted trunk: thus we have a simple boucheing machine 

 or drill lathe. 



In the mean time, the train artificers will have bent an axletree, or 

 any other convenient piece of iron, into the shape and form of a brace, 

 whilst other smiths will have forged out a four-cornered square cutting 

 tap ; with this square tap inserted in the brace, the artillery men may 

 be set to work to enlarge the injured vent. The smiths mean time are 



