132 Proceedings of the Royal Society of Edinburgh. [Sess. 
Another feature clearly shown by contrasting curves A and B is that while 
in the dry condition represented by the former, a temperature over 100° C. 
brought about the most marked diminution in efficiency of absorption, such 
a temperature in the second series was not so deleterious. In the latter 
series, in the circumstances admitting of maximum extraction, the granules 
on being taken from the test cartridge were found to have considerably 
increased in size and to contain relatively little unused caustic soda. 
III. Gaseous Mixture before entering the Caustic Compartment 
was saturated at 37° C. 
The temperature and hygrometric state of the stream of air and carbon 
dioxide were kept under observation. In this series the lower compartment 
of the case contained no water. On the results being recorded in graphical 
form (curve C, fig. 2), the curve was found considerably to resemble that 
of the last series ; at the optimum temperature extraction was again between 
70° and 90 c C. The maximum extraction was 72 per cent, of the carbon 
dioxide. The remarks as to the condition of the caustic soda in the last 
series equally apply to this. 
IV. Gaseous Mixture saturated at the Temperature at which the 
Caustic Soda was maintained. 
In each of these experiments the lower compartment E (fig. 1) was half 
filled with water, which was then kept at a definite temperature. The 
ingoing gaseous mixture flowed over the surface of the water before 
entering the caustic compartment. The results of the series are shown in 
curve D (fig. 2). The maximum extraction was 65 per cent., and the best 
