104 lftature'0 /HMraclea. 



water and gradually introduce it into a freez- 

 ing mixture made of broken ice and salt. 

 Immediately the water will begin to fall in 

 the tube, showing that it is contracting under 

 the cold, and it will continue to contract until 

 it reaches a temperature of 39 degrees Fah- 

 renheit, when it will come to a standstill and 

 then proceed to expand as the temperature of 

 the water lowers. When it reaches the freez- 

 ing point the fluid can no longer rise in the 

 neck of the flask, which is broken by the sud- 

 den expansion that takes place at this point. 



To show what an irresistible power resides 

 in the atoms of which the body is made, let us 

 take an iron flask with walls one-half inch or 

 more in thickness; fill it with water and seal 

 it up by screwing on the neck an iron cap ; now 

 plunge it into the freezing mixture, and the 

 first effect will be to contract the water unless 

 it is already below 39 degrees Fahrenheit, but 

 when it reaches that point expansion sets in, 

 which continues to the freezing point, when a 

 greatly increased expansion takes place sud- 

 denly. The walls of the iron flask, although 

 a half-inch in thickness, are no longer able to 

 resist the combined efforts of the billions upon 

 billions of the atoms of which the water is 

 made up, in their individual clamor for more 

 room, hence the flask is shivered into pieces. 



There are one or two other substances which 

 are exceptions to the general rule, but we will 



