20 
the apparatus to be described, will be found to answer well. 
Instead of using a capillary with a moveable and adjustable 
scale employed by Traube, I find that a piece of thick 
thermometer* tubing, with a fine round capillary, *155 mm. 
bore and about 26 cm. long, which was supplied to me by 
Mr. L. Casella, of London, served my purpose excellently. 
Along its whole length it was etched in millimetres. By a 
very simple arrangement of a mirror, usually used in such 
determinations, it is a matter of a little practice only, to be 
able to read off the scale to tenths of a millimetre with a 
pocket-magnifying glass. 
The first point to be determined before employing this 
tube was, whether a piece of thermometer tubing, *155 mm. 
bore, could be thoroughly cleaned and dried without deterio- 
rating with use. The tube was thoroughly cleaned with 
ether or alcohol, after each determination, by plunging it 
half way in pure dry ether, so that the ether rose at least 
two-thirds of the distance up the capillary. By bringing 
the lower end on to a piece of clean silk cloth, the capillary 
was rapidly emptied, and this process repeated three or four 
times, and finally dried by the following arrangement. 
The thermometer tube is placed in an outer tube of glass, 
closed at one end and constricted in two places. At the 
open end of the outer tube a plug of cotton wool is inserted 
round the thermometer tube, which serves to filter the air 
passing into it. The thermometer tube is attached by a 
piece of india-rubber tubing to a narrow glass tube con- 
taining cotton wool ; and by a longer piece of india-rubber 
to a calcium chloride tube, which may be closed by the 
pinch-cock and india-rubber tube. The glass tube, which is 
perfectly cleaned before use, is plugged with cotton wool 
when not required. In order to dry the capillary, the appa- 
ratus is fitted up as described, and the outer tube heated. 
