OF LIGHT BY TURBID SOLUTIONS. 193 



Exp, XVI. — Comparison-diflFusion contains 19' 2 cub. c. 

 in 500 cub. c. 



A B O D 



1*6 i'S8 i'59 132 



Many of the above numbers are close approximations. 

 I also tried columns of the lengths given by theory in all 

 experiments, except in the ninth, where by an oversight I 

 neglected to do so. The tints so obtained were in every 

 case satisfactory until I reached Experiment XIV. In 

 this and in the succeeding experiments I thought that 

 columns of the theoretical lengths gave tints slightly lighter 

 than the standard diflPusion. On some occasions I have 

 wavered in my opinion that the theoretical column gave 

 too light a tint in the fourteenth experiment. At another 

 time I got the foUovring result : — 



Exp. XVII. — Comparison- diffusion contains 9*6 cub. c. 

 in 500 cub. c. 



A B D 



2*8 2*95 2-87 2*65 



Here again the number under C is a little greater than 

 that under D. I afterwards repeated the experiment with 

 this variation — that the standard diffusion was contained 

 in the comparison-cylinder and the comparison-diffusion 

 in the standard cylinder. 



Exp. XVIII. — Standard diffusion contains i"2cub. c. in 

 500 cub. c. ; length of column 22*6. 



Comparison-diffusion contains 9*6 cub. c. in 500 cub. c. 



A B 







D 



285 3-07 



2*96 



2-g2 



On another occasion I got :— 



- 





A B 







D 



285 315 



3-0 



282 



SER. III. VOL. VII. 









