NATURAL PHILOSOPHY. 179 



He first exposed a number of capillary tubes, of diameters varying from 

 0'0074 inch to - 1 inch, and containing columns of water about 12 inches 

 long, to the air. The exposure lasted seven days, during which the temper- 

 ature never rose above 28' -5 Fah., and went down every night below 23 

 Fah. Upon withdrawing the tubes, all those whose diameter was greater 

 than 0'3G inch, had frozen; and all those whose diameter was less than 

 0'27-j inch, had remained liquid, nor did a sudden blow cause them to freeze. 

 By arranging the tubes in an inclined position, so as to plunge them in a 

 vessel of water, it was found that the formation of the ice externally, favored 

 their freezing. The two tubes of least diameter (0'013 and 0'0074 inch) alone 

 remained liquid. 



The sheet of water between two plates of glass, pressed together by 

 screws, will not freeze; but, if they be simply laid on each other, the sheet 

 which is then thicker, will freeze. 



Blocks of ice, from 3 to 4'5 inches cube, were placed in a hydraulic press, 

 and reduced to sheets of a few hundredths of an inch in thickness. Although 

 the temperature of the air was only a few degrees above the freezing-point, 

 the water trickled from the blocks on all sides. 



In order to prevent the expansion of the water during freezing, a quantity 

 was introduced into a cylindrical cavity of about 0'24 inch in diameter, in a 

 heavy prism of wrought iron. The water in the cavity was compressed by a 

 powerful screw, and then exposed to cold. The water remained liquid" at 

 2G'G Fah. In an attempt to reduce the temperature to 23 Fah., the appara- 

 tus began to leak. 



A quantity of water was then introduced into a cavity in a similar prism, 

 of steel, and, after being frozen, the ice was compressed by means of a pow- 

 erful screw moving a copper cone. The apparatus was surrounded by a 

 freezing mixture, the temperature of which varied from 0-4 to G'7 

 Fah. ; the temperature of the air was below 32, and the movement of the 

 screw was performed so slowly as to make but two turns (or forward mo- 

 tion) of - 36 inch in four hours. The ice was liquefied by the pressure, as 

 was indicated by the position of a small wire index which had been frozen 

 into the mass. 



The pressure to which it had been exposed Avas 13,070 atmospheres, by 

 which the freezing-point was reduced below Fah. 



ICE PHENOMENA. 



A recent number of the Canadian Journal of Industry and Science contains 

 some interesting information regarding the expansion and contraction of 

 ice, as observed on Rice Lake, C. W., by J. H. Durable, C. E. A bridge of the 

 Cobourg and Peterborough Railway runs through this lake, and in the South- 

 ern States, or in a mild climate, it would have answered every purpose; but, 

 with the expansion of the ice on this lake, in such a cold climate, it has 

 become a complete wreck. Glare ice is that which is smooth on the surface; 

 it has been found that such ice, when acted on by the mid-day sun, is im- 

 mediately set in motion by expansion, and it generally sets in towards the 

 shore. Sometimes this movement is very gradual, and accompanied with a 

 slight crackling noise; sometimes it is rapid and violent, and accompanied 

 by a succession of vigorous jerks, and a hollow, rumbling sound, seemingly 

 from under the ice, while at intervals there occur loud and sharp reports, 

 like those of cannon. 



