C. M. Warren on Organic Elementary Analysis, 395 
___is introduced into the end of the combustion tube, and broken 
_off by pressure against the side of the tube; the bulb itself is 
then allowed to drop in, and the end of the tube immediately 
closed with a perforated cork containing a glass tube, 4, connect- 
ing it with the drying apparatus, This connecting tube is con- 
structed of hard Bohemian glass; the anterior end of which is 
drawn out to a short, blunt point, and the opening nearly closed 
in the blowpipe flame, to the size of a small needle; the object 
of which is, to increase the rapidity of the flow of oxygen at 
that point, and thereby diminish the liability to loss from diffu- 
‘sion of gases or vapor backward into the drying apparatus, 
which is always too liable to occur when the posterior end of 
: the combustion tube is not sealed. 
eh aie een eas, Re 2 
connecting tube is packed wit bestus in the same m 
the combustion tube, and during the combustion is heate h 
one of Bunsen’s burners. In case vapor of the substance should 
reach this tube, notwithstanding the above precaution against it, 
it could not reach the drying apparatus as such; but would be 
the end of the combustion tube. 
In the performance of an analysis, the first step should be to 
expel the moisture from the combustion tube, while hot, by 
passing through it, for some time, a stream of dry air from the 
gasometer.’ The tube should then be filled with oxygen, before 
the substance, if volatile, is added; as otherwise particles of un- 
burnt substance might escape during the displacement of the air, 
d occasion loss. The absorbing apparatus, having n pre- 
viously weighed, is then attached, and, if the excess of oxygen 
employed is to be saved, the oxygen again admitted to expel 
Much time saved and uncertainty avoided ting the anterior end of the 
ion tube, at the close of y's operations, with a set of stationary dry 
tubes of ample capacity, which may stand back of the furnace out of the way, com- 
ication with which is establis' by s of »t ’ 
ing a tus, At the close of work, the anterior end of the combustion tube 
should Athy tightly corked, the fire extinguished, and the tube allowed to cool in 
dry air, It would thus be always ready for immediate use. 
