398 



Professor Sir James Dewar 



[Jan. 18, 



When the vahies were plotted with time, contraction cnrves were 

 obtained for both vohime and surface. By taking tangents to the 

 vokime and time curve at successive intervals of time, the corre- 

 sponding rates of gas transference — - were deduced. 



Fio. 85. 



Fig. 30. 



The third segment thus gave the values shown in Table III. for 

 air transference through the black lilm composed of 3^ per cent 

 ammonium oleate and 33 per cent glycerin. 



Three sets of these columns in the 200 litre globe were tried. 

 The first was the largest in volume, and took 101 days to pull apart. 

 Figs. 35 and 3G show the appearances at start and tinisb, the total 



