Use of the Galvanic Battery in Blasting. 33 



Art, IY. — On the use of the Galvanic Battery in Blasting ; by 

 Hamilton K. G. Morgan. 



To the Editors of the Philosophical Magazine and Journal. (Lond ) 



Johnstone Castle, Wexford, May 24, 1839. 



Gentlemen — I beg to trespass on your time by this letter on 

 the use of the galvanic battery, instead of the fuze in blasting. 



The papers have given short desmptions of the experiments 

 made at Chatham, bat all the details were not given. I com- 

 menced my experiments on blocks of the old trees that were 

 blown down by the late storm. I first prepared an igniting car- 

 tridge by joining two pieces of clean copper wire to the extremi- 

 ties of a steel wire taken from the scratch brush, such as is made 

 use of by gun-makers ; this steel wire is fastened to the copper 

 wires by waxed silk ; the length of steel wire to be deflagrated is 

 one-fourth of an inch; a piece of very slight wood is spliced to 

 both copper wires to protect the steel wire from any accident — it 

 makes the whole strong and more convenient to be introduced 

 into the small cartridge, which is either a quill or a small paper 

 tube. They are filled with fine powder, and made air and water- 

 tight, to prevent the powder from getting damp and rusting the 

 steel wire ; a second small piece of wood is then fastened to this 

 small cartridge and the copper wires ; one of the wires is bent 

 over this piece of wood and brought up at an angle with the 

 other upright wire. This is my exploding cartridge: it cannot 

 be easily put out of order. The wires of the cartridge have only 

 to be made bright before they are fastened, by twisting them 

 round the positive and negative wires of the battery. I always 

 place the cartridge deep in the hole made to receive the powder, 

 in order that the pressure from the turnpeg may be taken off by 

 the quantity of powder above it. 



The wire I made use of is the common copper-bell wire. The 

 battery is the old Wedgwood trough, with 4-inch plates, double 

 coppers. I prevent the zinc plates from touching the copper by 

 small pegs of wood passed through the four corners. Wooden 

 troughs with movable divisions were tried, but not with any 

 good result. A wooden trough with the plates in a frame of 

 wood, with varnished paper between the copper, was tried, but 

 the porcelain trough far surpassed them. My first experiment 

 Vol. xsxviii, No. 1.— Oct.-Dec. 1839. 5 



