58 THE WONDERFUL CENTURY. CHAP. vn. 



Centigrade. Hence, beginning at zero, if a gas could be 

 cooled continuously down to 273 C., or 461 Fahr., it 

 would not only be reduced to a solid, but would cease to 

 have the power of further contraction. Hence this 

 point is termed the absolute zero of temperature, and 

 Lord Kelvin has arrived at the same result by quite dif- 

 ferent means. With the total absence of heat it is be- 

 lieved that all chemical action would cease, so that the 

 universe would consist wholly of solid and chemically 

 inert matter. Heat, therefore, seems to be the source of 

 all change in matter, and the essential condition of all 

 life; while the other vibrations of the ether, which we 

 know as light and electricity, may be also essential. 

 Ether, therefore, appears to be the active, matter the 

 passive agent in the constitution of the universe ; and the 

 recognition of the existence of the ether, together with 

 the considerable amount of knowledge we have acquired 

 of its modes of action, must be held to constitute one of 

 the most important intellectual triumphs of the nine- 

 teenth century. 



