POLYMORPHIC TRANSFORMATIONS OF SOLIDS. 



79 



explode; this will be described in detail later. Since the transition 

 line of KCIO3 does not cross the axis of atmospheric pressure, one 

 filling of the apparatus and one series of runs was sufficient to deter- 

 mine all the data of the transition curve. A run with a second filling, 

 pressure transmitted by mercury, was made to more carefully de- 

 termine the velocity effects at 0°. 



The reaction is a slow one, and shows considerable lag on both 

 sides of the line. The pressure limits within which the equilibrium 

 values were enclosed are wider than usual, the limits being very much 

 widest at the low temperatures. The wide pressure limits at the low 

 temperatures make the AV values rather irregular at the low end of 

 the curve. The phenomena of reaction velocity are especially inter- 

 esting and easy to follow in the case of this substance, and an especial 

 study was made of them. These 

 will be given in detail in another 

 place. Attention may be called, 

 however, to an experiment at 0° 

 extending over four days. The 

 equilibrium pressure found under 

 these conditions is considerably 

 higher than that to be extrapolated 

 from the high temperature values. 



The experimental results are 

 shown in Figure 11, the computed 

 value of AH and AE in Figure 12, 

 and the numerical values in Table 

 V. Within the limits of error, the 

 transition line is straight, and the 

 curve for AV is also straight, with 

 a very small slope. 



The new phase was not known 

 before, so there are no other values 



J.00> 



Pressure, kgm./cm.' x 10' 

 Potassium Chlorate 



for comparison. 



No other forms were found be- 

 tween atmospheric pressure and 

 12000 kgm. at room temperature, 

 and none between 3000 and 12000 

 at 200°. There are, however, rea- 

 sons for suspecting that there may 



possibly be another modification at 0°, and that the transition line 

 drawn should properly end in a triple point above 0°, with the line 



Figure 11. Potassium Chlorate. 

 The observed equilibrium tempera- 

 tures and pressures, and the changes 

 of volume. 



