1026 
section, the observation vessel is supposed in a position that the 
windows B are horizontal (hence turned through 90° compared with 
fig. 2, the position in which the observations are made. The qua- 
drangle in the figure represents a glass window in the back wall 
of the thermostat (not to render the figure too indistinct it has been 
drawn much larger than it is in reality); of course a glass window 
in the front wall corresponds with it. The thermostat has a capa- 
city of + 40 L.; it is provided with a vigorous stirring-apparatus 
thermoregulator, and thermometer; it rests on a solid stand of LL 
shaped bar-iron. 
The coupling S, is of no importance for the experiments de- 
scribed here; it only serves to make it possible if required to 
connect the press with other conduits, and if necessary, to clean 
T the tubes. The coupling S,, on the other hand, is neces- 
[En] | sary for the filling of the apparatus, as will appear when 
(5 lun | the filling is deseribed. Fig. 4 gives a section of these 
Hach couplings. em ae oye | | 
(. H Re At the tops of the tubes C, and C two cones D, and 
<t” DD, have been serewed, which exhibit again two cones 
Fig. 4. fitting into each other at their ends. By means of the 
glands /, and ME, with hexagon, D, and D, are pressed against each other, 
and a steel-to-steel closure is again reached tight even at the highest 
pressures. It is preferable to take the serews with which D, is 
fastened to C, and PD, to C, for such couplings with left-handed 
thread, that when /2, and Z, are tightened, D, and D, are not 
unscrewed, but on the contrary, are screwed tighter. 
In connection with the method of filling another particular of the 
apparatus deserves being mentioned, which appears from fig. 5. This 
figure presents a side view of the observation vessel, a section ot 
which was given in fig. 2, with the parts in connection with it, 
