384 



Mr. R. W. Boyle on the Absorption of 



same volume and same size grain. The wood charcoal 

 weighed 0*77 gm., animal 2*25 gms., and coconut 2 # 17 gms. 



The curves show that coconut charcoal absorbs the most, 

 iind ordinary wood charcoal the least o£ the three, and that 

 the variation in absorptive power is very marked. In fact, 

 two different samples of the same kind of charcoal can show 

 appreciably different absorbent powers. I have had samples 

 of coconut charcoal differing considerably in this respect, 

 the better absorbers being softer, less gritty, and less dense 

 than the others. 



(b) Speed of the air-current. 



An inspection of the curves mentioned above, or of any of 

 those following, will show that the amount of absorption 

 depends on the speed of the air-current which conducts the 

 emanation through the absorbent material. 



The absorbent must have time to absorb, and at quick 

 speeds it does not get as good a chance. 



The following facts, taken from fig. 5 and tabulated, 

 illustrate very well (a) and (6). Here the percentage 

 absorption for any given speed is represented by 



Difference between non-absorption and absorption ordinates 

 Non-absorption ordinate 



The table shows that the percentage absorption is increased 

 as the speed of the air-current is decreased. 



Table III. 



Absorbent. 



Speed of 

 Air-Current. 



Ionization 



Current, 



Absorption. 



Ionization 

 Current, 

 Non- 

 Absorption. 



Per cent. 

 Absorption. 



Wood 

 Charcoal. 



0-7 

 10 

 1-5 

 4-5 



8-0 



55 



94 



139 



86 

 63 



93 

 138 

 164 



92 

 665 



409 



31-9 



14-8 



6-5 



5-3 



Animal 

 Charcoal. 



0-5 

 0-7 

 1-0 

 20 



11 



31-5 



62 



98-5 



55 



93 



138 



164 



80-0 

 66 2 

 55-0 

 39-9 



Coconut 

 Charcoal. 



1-5 

 20 



4-5 

 8-0 



16 



28-5 



43 



40 



164 

 164 



92 



66-5 



90-3 



82-6 

 53-3 

 39-8 



