APPLICATIONS OF GAS ANALYSIS. 
IV. THE HALDANE GAS ANALYZER. 
By YANDELL HENDERSON. 
(From the Physiological Laboratory, Yale Medical School, New Haven.) 
(Received for publication, October 30, 1917.) 
This apparatus has such marked advantages for precise analysis 
of gas mixtures containing less than 30 per cent of oxygen, COs, 
and other absorbable or oxidizable gases that it has become the 
standard instrument. Nevertheless it has several features in 
which experience in this laboratory has shown that it may be 
simplified with advantage. The form of apparatus shown in 
Fig. 1 is the result of this experience. The advantage of this form 
is not in its use during analysis,—for this involves no significant 
change,—but chiefly in the ease with which it can be taken 
apart and cleaned (a feature in which the usual form of the 
apparatus is a source of much annoyance and waste of time), 
and in the lessened liability to ‘‘frozen’” cocks and breakage. 
It has a minimum of rubber connections and only one glass stop- 
cock. (I have also tried out an apparatus with connections of 
glass tubing of only 0.7 mm. bore, but have found this too small. 
The usual bore of 1.1 to 1.8 mm. is best.) 
The particular features of this form of the apparatus are: (1) 
a 4-way glass stop-cock shown in Fig. 2; (2) the adjustment of 
the volume of the control tube by means of a screw pinch-cock 
on a bit of rubber tubing on the lower end of the tube; (8) two 
large test-tubes in which the absorbents KOH or NaOH and 
potassium pyrogallate' are placed. The fine adjustment of 
pressure-volume is made by raising or lowering the test-tube 
containing the alkali. Tor the oxygen absorption the test-tube 
containing the pyrogallate may be raised and lowered, to avoid 
1Sodium pyrogallate (as described by Shipley, J. W., J. Am. Chem. 
Soc., 1916, xxxvili, 1687) has not proved satisfactory in this instrument. 
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