EFFECTS OF PRESSURE ON NITRATES. 



5S3 



expected, because iron is known to deposit silver from solution. 

 There was, however, some slight amount of decomposition somewhere, 

 as shown by the escape of a few bubbles of gas when the apparatus 

 was opened after the measurements at high temperatures. This 

 decomposition might be either in the kerosene or the AgNOs. No 

 such decomposition could be detected, however, after the measure- 

 ments at the lower temperatures and higher pressures. Possibly 

 this slight decomposition might explain the two discordant points 

 which were discarded, although there are other possibilities, such as 

 the fact that the change of volume is so small that a very slight 

 amount of hysteresis would produce a comparatively large error. 

 On repeating the measurements the possibility of hysteresis was 

 avoided as far as possible by running the pressure back and forth 

 several times over the transition before beginning the measurements. 

 The quantity of AgNOs used in these runs varied from 61 to 103 gm. 

 The direct experimental points are shown in Figure 1, the computed 

 values of AH and AE in Figure 2, and the numerical results are col- 

 lected in Table I. The only points of either determination which 

 have been discarded are the two bad Av points already mentioned; 

 one of these was about 30% and the other 12% too high. In view of 



TABLE I. 



Silver Nitrate. 



