57 1 
Bonnier and Mangin for the Analysis of Air . 
which can easily be constructed from copper wire and wood. The wire 
is bent in such a way that the handles of the tubes are readily removed or 
pressed into position. 
The tubes for the absorbing liquids should have their edges fused in 
a flame till they just will not go right down over the capillary tube, but 
stop at the base of the tapering end of it. The acid-tube, on the other 
hand, as also the air-tubes, should be wide enough 
to go right down over the capillary so that a 
thorough neutralization of the absorbing liquid 
is ensured. 
The reagent tubes are most readily filled by 
first pouring in the reagent to about a centimetre 
from the open end, and then filling up with clean 
mercury. On inverting over mercury, the slight 
escape of liquid is removed with soft tissue or 
filter paper. 
As the absorbing liquids tend to creep out of 
their respective tubes, the pyrogallate tube should 
be kept by itself in a separate dish of mercury. 
The tubes are transferred to the apparatus 
closed below by the finger, and pressed down 
over the end of the capillary tube. On now 
turning the handle A (Fig. i) in the required direction the liquid or air is 
drawn into the tube. 
Reagents. 
Washing liquid : 5 % sulphuric acid. If dilution of the concentrated 
acid results in the formation of a slight precipitate this should be allowed 
to settle before use. 
Solutions for absorption: (1) A 10 % solution of caustic potash! 
(2) a solution of potassium pyrogallate, made 1 by adding 10 grammes of 
pyrogallol to 100 c.c. of a nearly saturated solution (sp. gr. 1 • 55) of caustic 
potash (not purified by alcohol 2 ). 
Procedure. 
To clean the apparatus before an analysis a bubble of air is introduced, 
then clean acid rapidly drawn in as far as zero on the graduated tube. The 
air-bubble traps any drops of mercury which are left behind where the tube 
is dirty. The acid is slowly expelled, and again rapidly drawn in, the 
process being repeated, if necessary with a change of acid, until the mercury 
1 See Haldane : Methods of Air Analysis, 1912, p. 13; and for further details, Benedict, 1 . c., 
pp. 80 and 1 1 2. 
2 Hempel : Gas Analysis, 1911, p. 115. 
