PARADOXICAL CONTRACTION. 



< A 



< B 



fall again, and the water will re-contract. The 

 colder the water gets the more it contracts, so 

 that the water in the column, which was arranged 

 to stand at the level A when we began cooling 

 the flask, will keep sinking till it 

 gets down to the level B, when 

 the water in the flask is at about 

 4 C. or 39 F. a few degrees, 

 that is, above freezing and melting 

 point. Before we have cooled it 

 to this point it would be very 

 natural for us to think that as 

 some cooling had caused some 

 contraction, further cooling would 

 cause further contraction indefi- 

 nitely. This, however, would be 

 a mistake. It would be pushing a 

 principle too far, as did the man 

 whose wife on Saturday night 

 brought home a new kind of stove, 

 which she had been assured would 

 save half the coal. " Let's have 

 another next week/' he said, "and 

 save it all." 



As in everyday affairs, so in 

 scientific matters, it is possible 

 to push a principle too far. It is often found 

 that a law or principle which is almost ex- 

 actly true in ordinary circumstances, requires 

 much modification in extreme cases, and is 

 suspended altogether when the case is so 



J 129 



FIG. 30. EXPAN- 

 SION AND CON- 

 TRACTION OF 

 WATER WITH 

 HEAT AND COLD. 



