SOLID, LIQUID, AND AERIFORM STATES. 157 



CHAPTER XVIII. 



' THE SOLID, LIQUID, AND AERIFORM CONDITIONS OF 

 MATTER DETERMINED BY THE EXTENT OF ITS MO- 

 LECULAR VIBRATION. 



HPHE component particles of the air and waters 

 are the only substances that are commonly in 

 a fluid state. Every kind of elementary matter has 

 been found to be reducible to solid, or crystalline, 

 formations, by bringing the particles together by 

 extreme pressure, while their vibrations are reduced 

 to an extreme degree by frigorific mixtures, as by 

 contact with frozen carbonic-acid gas, at a temper- 

 ature of 1 39 below zero of Fahr. The changes of 

 the seasons produce the various changes of water, 

 from crystals to liquid and aeriform states. At the 

 ordinary temperature of the atmosphere mercury 

 remains liquid, but becomes crystallized, or frozen, 

 at 39 below zero of Fahr. 



All other solid crystalline metals may be deemed 

 frozen, if they are considered relatively to the 

 temperature at which their component molecules 

 become liquefied by heat. As the temperature on 

 the earth's surface is rarely reduced to 39 below 

 the zero of Fahr., molecules of mercury, when not 



