1508 
TABLE 9, 
EE AE EN MEET EARN SEN ER EEEN A ETE OT NN ENE 
t _ P (observed) P (calculated) Error 
184.5 0 0:42600 IN o.4a6h |) 0.426 a Mie | = 
256 51 | 57 37 22 0 | — 20 | —35 
284 156 274 156 | 80 | +198 SOS 
332 5402880 1340 | 540 | +2340 | +800 | 0 
from table 9, in which the three observations with dry NH,Cl have 
been given. But at the same time the heat of conversion is much 
too great. Then the angle between the lines thus traced and the 
line through the partial pressure (fig. 5) corresponds with 11.1, 8.2, 
and 4.8 kilogram calories, though it must be 1.03 kilogram calories. 
The line that corresponds with the last heat has been indicated 
dotted at the transition point in fig. 5. These calculations and 
fig. 5 will in my opinion make it sufficiently clear that the expla- 
nation which Prof. Wrescuriprr considered the most probable, is 
untenable; the only objection that can be made against the executed 
calculations is that experimental errors in the quantities used, and 
also the way of extrapolating may perhaps appreciably change the 
result. To obviate this objection I will add the following conside- 
rations. 
12. Possible errors in the calculations of § 14. 
To detect all possible sources of error in the calculations we 
should know in the first place the accuracy of the data used. The 
determinations of the vapour pressure carried out by Prof. Smrra, are 
without doubt very accurate; the observations lie very well on a 
curve with a regular course, as is also clear from figure 4. The 
errors in these observations (table 8, column 2) can have only little 
influence. Much more weight is to be attached to the errors of 
observation in the rate of dissociation (table 8, columm 3). To 
examine the influence of this the values found for log K have been 
drawn as function of 7’! in fig. 6, and besides the curve has been 
given which Smrrn considers the most probable. That the observed 
points deviate comparatively much from the curve, is easy to under- 
stand, when we consider that the experimental errors in « appear 
greatly enlarged in A. This is clear, as: 
de 
KZ 
la’ RT 
