[BOYLE] TEMPERATURE AND VELOCITY OF GAS CURRENT 101 
an absorbing substance of the same actual volume, all the experimental 
conditions being the same in both cases. 
Then, since these currents are proportioned to the amount of emana- 
tion in the testing vessel, the per cent absorption must be given by 
(CS =) (MONO eee: mac dt SR (5). 
1 
4 2W 
From (1), ù KNesïll—es 

) 
TZ s7 AW 
Wea ING e net a eet 
eS SP 
Hence ; Ce UT sy hOU tele vena El 
Al 
Therefore the per cent absorption for any speed of air current 
q, and actual volume of absorbing substance V, is given by — 
and from (3), a 



—$ Le 
% absorption = 100 {1 —e a) TR Eee (5 a). 
Again, from (1) and (3), we have 
; -sV, 
— = € q es eee er nes ss enesee ss susssssssess (6) 
1 
Hence, if we should plot a curve with values of iz as ordinates and 
1 : 
of oR us abscissae, the curve would be exponential. 
‘en 1 —$ Fi 
Since ais es 
li 
dy sy ie 1 
Mog EN SN Mu (7) 
4 q 4 
ep . à, . e 
Then, if we plot a curve with logs — as ordinates and the reciprocals 
i 
1 
of corresponding values of g as abscissæ, we should get a straight line 
with slope equal to —sV,. From this we have a method of finding the 
relative absorptive power of different solid materials, for V, can be 
made the same in all cases, and therefore the slopes of the logarithmic 
straight lines will be proportional to the corresponding values of s, the 
coefficient of absorption, which is a measure of the absorptive power. 
The method may also be used to find how different temperatures effect 
the absorptive power of any material. 
