1250 
Owing to the peculiar method 
followed by Dr. pr Leeuw to observe 
for a few minutes only whether the 
dilatometer exhibits a rise or a fall, 
one gets from his communication 
the impression as if each time, with 
the different (rising) experiment-tem- 
peratures, a similar phenomenon 
repeats itself. Now, such is by no 
means the case. Only once or twice, 
the said maximum occurs. I have 
observed repeatedly that it then 
returned no more. The slight increase, 
or decrease observed by him at the 
subsequent temperatures have no 
significance, moreover, such trifling 
Neon 
Fig. 1. 
values never have a definite meaning; 
the dilatometer is not an instrument of precision not even when 
the best acting thermostat is used. 
In order to obtain really trustworthy results the experiments 
should be so arranged that the reaction studied exhibits a suitable 
rise or fall; this should then surely exceed a few m.m. 
Below are given some of my investigations. 
As, for these experiments, glacial acetic acid is a much more 
appropriate liquid than turpentine-carbon disulphide (see communi- 
cation IV), these experiments have been carried out with that liquid. 
The thermostat has been described in communication (HD. The 
sulphur was treated exactly as directed by Dr. pr Lervw. 
Table I contains the result of a series of experiments represented 
graphically in fig. 2. We notice that, when we wish to attribute 
the great rises at 76°.2 and 88°.0 to conversions according to the 
scheme of fig. 1 it becomes inexplicable why at the temperatures 
86°.7 and 91°,9 the phenomenon does not appéar, but returns at 
Y7°.8. Moreover, the conversion at the latter temperature exhibits 
the plain character of a conversion above the transition temperature. 
From this series I already gained the impression that the maximum 
occurring at 76°.2 and 88°.0 has nothing to do with the conversion 
Simeon 
One might imagine that, during the time corresponding with the 
falling branches in A and B fig. 2, so much, S, has been regene- 
rated that at the subsequent rises of the temperature one does not 
arrive any longer above the line AC in fig. 1. True, that difficulty 
