( 130 ) 
illustrate that §. For that purpose however the drawing, to be found 
in the description of the eryogenic laboratory by Prof. Marutas !) 
is better adapted. Whereas the apparatus described by him was made 
for measurements in a permanent bath of oxygen with a capacity 
of from 1/, to Ys Litre, in the experiments of Dr. HASENOEHRL, 
treated of in Communication N°. 52, a cryostat (boiling-glass with 
boiling-case) was used, designed on the same principle, but which 
contained a bath with a capacity of from Ys to °/, Litre ®). 
This also offers the advantage of being more quickly and easily 
mounted, and being more certainly air-tight, thus being better able 
to keep the enclosed gas pure and dry. It was built by Mr. J. J. 
Curvers, head mechanic of the cryogenic laboratory, to whom I 
owe my best thanks for the care and ingenuity displayed in these 
works. Plate I gives an elaborate drawing (1/3 nat. size) of the 
apparatus together with the electric condenser for measurements with 
liquefied gases *®), which was fastened in it in the experiments of 
Dr. HASsENOERHL. Hence this plate may serve at the same time to. 
illustrate the description of his research. 
The gas liquefied under pressure e.g. liquefied oxygen at —140°C. 
from the ethylene boiling-flask, (Comm. N°. 14 § 5) is introduced 
by means of the tube a, which is wound in numerous turns 5 
round the piece of wood carrying the cock. When the apparatus 
has been working for a short time, part of the gas streaming out 
in drops and clouds passes along these turns and so even further 
cools the liquefied gas before it escapes. The cock-pin v having been 
opened by means of the handle A, the gas passes through a filter 
J filled with glasswool enclosed by gauze, and flows out through 
the tube ¢ against the cylindrical glass C, which fits exactly round 
the turns of the spiral 5. If we apply the eye to the observing 
tube K,*), and the light obtained by means of the illuminating 
tube Vj is sufficient, as long as liquid flows out from the tube c 
we see the jet spread out in a fan over the glass C, the jet-catcher *). 
Part of the cooled liquid escapes along the spiral b, as remarked 
1) Marnras, le laboratoire cryogène de Leiden, Revue générale des Sciences, 1896, 
p. 387 fig. 3. 
2) By placing other beakers in the boiling-glass the apparatus may be used for 
baths of almost twice that volume. 
*) For this compare the section Pl. I of Comm. N°. 52, 
*) The construction of V, is exactly like that of A,; in the drawing the front-view 
of K, or V, is given near /,. 
*) The disappearance of this fan-shaped form indicates that no ‘more liquid is 
supplied by a and that we must therefore shut the cock. 
