158 VIBRATORY STATES OF MOLECULES. 



polarized with molecules of other kinds of element- 

 ary substances, exist in a liquid state, and are hence 

 denoted " quicksilver." By artificially intensifying 

 the vibrations of the molecules of quicksilver to 

 680 Fahr., they yield to the vibration of the 

 electric ether intervening between the molecules, 

 and become expanded and diffused in invisible 

 vapor, floating in the air like steam. 



This example of the three states of existence of 

 molecules in solid crystals, in a liquid state, and 

 in an aeriform state illustrates the three different 

 conditions of existence of all other kinds of element- 

 ary matter ; not even excepting the once termed 

 "permanent gases" such as oxygen, hydrogen, 

 and nitrogen which have been recently liquefied 

 and solidified by extreme cold and pressure. The 

 boiling point of substances, or their evaporable 

 temperature, appears to indicate the commence- 

 ment of the extreme molecular vibration, which 

 separates the component parts of substances be- 

 yond the range of their reciprocal electro-magnetic 

 attraction. 



As previously described, the vibration of the 

 molecules of quicksilver increases uniformly from 

 the freezing to the boiling points ; as is evidenced 

 by a uniform expansion in the tubes of thermom- 

 eters. The increase of vibration of water, de- 

 veloped (as that of all other bodies) by friction 

 and percussion, has been adopted as a useful test 

 of the degree of heat producible by a definite 



