382 
furthermore special precautions had to be taken in filling the appa- 
ratus. Therefore the filling of the instrument was executed in the 
following way: The volatile liquid is contained in a sealed vessel 
A (fig. 1), which is placed in a Drwar-glass, in a mixture of solid 
carbondioxide and alcool. On continuous cooling the vessel is rapidly 
sealed to the further glass-apparatus, after the capillary glass-tube 
is broken off. While the fat-free stopcocks 7, and 7, are closed, a 
current of dry air, freed from water and carbondioxide by means 
of quick lime and sodium hydroxide, is introduced by 7. Then the 
tube 7’, is sealed off, and now the volumeter is sealed to the appa- 
Fig. 1. 
ratus, during which operation the air can escape through 7’,. This being 
finished, also 7’, is sealed off; then the stopcocks r, and r, are 
opened, and the whole apparatus is evacuated. Now the volumeter 
is placed into the cold bath, and the stopcock 7, is opened again; 
after the desired quantity of liquid is distilled from A into J’, during 
which the vapour in passing again the tube 5 filled with dry and 
pure BaO, gives off its last traces of humidity, the stem of V is 
sealed-off at a point lying considerably higher than the highest division 
of the capillary tube. 
Then the whole apparatus is accurately weighed. Now the volume- 
trical measurements are made at the desired temperatures; and 
finally the volumeter is carefully opened by removing the end of 
the. capillary tube, and after cleaning and completely drying, the 
empty apparatus is weighed again, together with the removed piece 
of glass. The difference of the two weights gives the weight of the 
liquid used, whose volumina now are determined at different tem- 
peratures, because the volumeter has been accurately calibrated 
previously. After the necessary corrections the specific. gravity at the 
said temperatures can be easily caleulated from these data. The 
capillary tube has to be completely cylindrical; they were thick- 
walled, and accurately calibrated by means of liquids, whose speci- 
fie eravities at a whole series of temperatures were exactly known. 
