CUTTING ICE 



3. Cutting Ice without Severing the Parts. 



This depends on the principle illustrated in 

 the last section, and the experiment a par- 

 ticularly pretty one requires little and simple 

 apparatus. First, we want a bar of ice, A B 

 (Fig. 28), the most 

 convenient way of ob- 

 taining which will be 

 to make it ourselves. 

 Get a large test-tube, 

 about one inch in dia- 

 meter ; or, where that 

 is not readily obtain- 

 able, a six-inch section 

 of hollow brass curtain- 

 rod from which all in- 

 ternal roughness and 

 burrs at the cut edges 

 have been removed, 

 and fitted with a cork 

 at one end. Fill this 

 vessel with water 

 within an inch of the 

 upper end, and close with a cork. Bury it 

 in a freezing mixture, such as that referred to 

 in the last section but one about eight 

 pounds of ice, crushed up to the size of peas 

 and beans (or of snow), mixed well with four 

 pounds of crushed salt. 



In less than half an hour the water will be 

 123 



FlG. 28.-ICE RE-FROZEN ON 



RELAXATION OF MELTING 



PRESSURE. 



