498 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



—35°. The change in reaction velocity between III and V at different 

 temperatures shows a greater and more striking change than that on 

 any of the other curves. At the upper end, in the neighborhood of 

 —20°, the velocity is explosive. It is possible to withdraw the piston 



TABLE XVIII. 

 Data for the Equilibrium Curve Ice III-Ice V. 



by an amount corresponding to nearly the entire volume change of the 

 reaction, and not be able to detect any change at all in the pressure, 

 so rapidly does the change occur. While only 15° lower, at —35° the 

 reaction runs so slowly that the attaining of complete equilibrium is a 

 matter of several hours. This is the reason that the attempt was not 

 made to prolong the equilibrium curve further. It is evident that we 



