482 THE POPULAR SCIENCE MONTHLY. 



spars are swayed up and sails bent, and the ship is again " all a taunto," 

 and all are anxious once more to feel the long roll of the ocean. The 

 open water is seen to the southward from the crow's-nest, but it is 

 some distance off, and the ship is held fast in the wintry grasp of the 

 ice. The month of June has come and gone, July is nearly at an end ; 

 if they are not shortly released, they will perhaps be doomed to spend 

 another winter in that inhospitable and inclement region. During the 

 preceding months those on board have not been idle, as a long line of 

 ashes, sand, and rubbish of all descriptions, thinly sprinkled from the 

 ship's bows in a long straight line to the southward, will testify. This 

 has been done with the object of penetrating and rotting the ice, the 

 dark color attracting the heat of the sun, so as to make a passage for 

 the ship to pass through. This dcA'ice has failed, and others must be 

 resorted to to effect their liberation. 



Blasting has been determined upon. Chai*ges of three pounds, five 

 pounds, and ten pounds of ordinary gunpowder will be prepared for 

 use, in tin canistei'S, with Bickford's fuse. If, howevei-, the new ex- 

 plosive " cotton gunpowder" should be the substance selected to carry 

 oiit this object, a small charge of about two pounds is prepared, primed 

 with its detonator, to which is attached a short length of Bickford's 

 fuse. Operations are commenced from the open water and carried on 

 toward the ship. A hole is made in the ice by means of a drill some 

 distance from its edge, and the charge is lowered down through this 

 until it reaches the water and is placed immediately under the ice. 

 The fuse is ignited, a sharp explosion takes place, and the ice is shat- 

 tered and rent in all directions. Men in boats, and others armed with 

 boat-hooks and long poles, at once assail the fragments, removing them 

 from the channel into the open water. These operations are repeated 

 until a clear channel has been made, through which the ship is able to 

 steam and thus effect her escape. The advantages which the " cotton 

 gunpowder " has over ordinary black gunpowder are numerous. It is 

 a much more powerful explosive, its proportionate strength to common 

 powder being as eight to one, but its great merit is said to consist in 

 its perfect safety. If put into the fi.re it will burn quietly, without any 

 explosion, nor will it explode on concussion. 



The practice of ice-blasting is not a new invention, and had been 

 much resorted to by the various search expeditions. Their plan was 

 simply to lower a glass bottle, or preserved meat tin, containing from 

 two to four pounds of ordinary gunpowder below the ice, and explode 

 it. The results were most satisfactory. Lieutenant Mecham tells us 

 that during Captain Austin's expedition, in 1851, a blasting-party was 

 employed for twelve days in detaching a floe from the eastern shore 

 of Griffith Island. With 216 pounds of powder they cleared away a 

 space 20,000 yards in length, and averaging 400 yards in breadth ; 

 this ice varied from three to five feet in thickness. The estimated 

 weight of the ice removed was about 216,168 tons. The heaviest 



