1917] 



on Soap Bubbles of Long Duration 



1!)3 



Table 4. — 25 per cent, glycerine, 4 per cent, alcohol, 5 per cent, soap ; 

 banging on glass tube. 



The corresponding rates calculated for similar bubbles 10 cm. 

 diameter would be : (I) 0-086 ; (2) 0*58 ; whereas a bubble subject 

 to water condensation, but still retaining some colour, contracted 

 from 11 cm. diameter on its 75th day to 10 cm. diameter on the 95th 

 day, being a diminution of 1 cm. in twenty days, giving an average 

 daily rate of gas transference per unit of surface equal to 0*025 cm., 

 or about one-third the calculated rate for a black bubble of the same 

 diameter. 



Table 5 may be amplified as follows, to show more completely 

 what is occuriing in bubbles of this size : — 



Table. 6. — Gas transference through 38 cm. black bubbles in air 

 (dilute glycerine-oleate solution). 



Kesults 



Diminution in diameter 



Diminution in volume 



Gas transference through each 

 sq. cm 



(i) 5 weeks l)lack* (ii) 2 weeks black f 



♦ No. (j) hanging on a glass tube. f Xo. (ii) less diluted than No. (i), and resting 

 on a steel wire ring. 



Vol. XXII. (No. Ill) o 



