EXPANSIBILITY. 269 



generated and extricated from gunpowder dur- 

 ing the process of detonation, is enabled to sap 

 and to undermine the strongest fortifications; 

 to project out of the mouth of a cannon a ball 

 to the immense distance of two or three miles ; 

 to explode the strongest shell from a mortar ; 

 to burst it into pieces, and carry death and des- 

 truction to surrounding objects.* 



In the various and multiplied discussions on 

 this subject, which I have had with numbers 

 of scientific men, and more especially with 

 many of my particular friends, who fill the 

 teacher's chair in some of our most celebrated 

 schools of science in this metropolis, I have 

 not found an individual among the whole mass, 



* Col. WILLIAMS, while serving at Quebec, filled differ- 

 ent iron bomb-shells of different sizes with water, and plugged 

 the fuEfhole close up, sometimes driving iron plugs with 

 a sledge hammer. When the water had been frozen, al- 

 though the plugs often weighed three pounds, they were 

 always forced away, by the sudden expansion of the air in the 

 act of freezing, like a ball impelled by gunpowder, to the 

 distance of 4 and 500 feet; and when the plugs were screwed 

 in the shell, the shell burst. Mr. Marian ascribes the ex- 

 pansion that takes place at the point of freezing, not to the 

 extrication of air, because he says that water deprived of air, 

 expands equally ; he, therefore, refers the effect to the new 

 arrangement of the particles of the water which takes place, 

 in the change which they undergo from a fluid to a solid state; 

 it is very probable that both causes operate to produce the 

 effects. 



