Transmission of Gases through Water. ob'5 



In order to provide in these experiments the means of 

 detecting whether or not the mechanical agitation of the 

 surface-layers of the water-columns caused a circulation of 

 the water to the bottom, a large crystal of potassium bi- 

 chromate was placed at the bottom of the tubes; but in no 

 case was the dissolved bichromate observed to rise above 

 the immediate neighbourhood of the crystal, and become 

 mixed with the water above it. 



The results of the last two experiments proved, as was 

 anticipated, that the downward streaming effect takes place 

 so rapidly when the surface of the water exposed to the air is 

 continuously agitated, that long- columns of water are com- 

 pletely saturated with atmospheric gases with comparative 

 rapidity. 



Experiments were next made in which the surfaces of 

 the water-column were kept broken by means of slow 

 currents oi air. It was thought that by their means it 

 would be easy to make comparative obseiwations on the 

 effect of agitating different thicknesses of the surface-lavers 

 of two or more columns of water by the same disturbing- 

 cause. 



Xo. 6. — Two tubes, each 1980 mm. long and 24 mm. bore, 

 were rilled with nitrogen-free sea-water. Each tube was 

 fitted with an indiarubber cork and fine glass inlet and exit 

 tubes of 3 mm. bore, and they were connected in series so 

 that the same current of air could be drawn through the 

 -urfaee-layers of each column of water. The inlet-tube 

 through which the current of air was first drawn dipped 

 100 mm. below r the surface of the first column, and the 

 second inlet-tube dipped 10 mm. below the surface of the 

 second column, of water. The current of air was not pre- 

 viously filtered. It was continued for 25 hours. At 

 conclusion temperature of room was 19°'5 C, and of the 

 jacket 15°'7 C. 



Sea-water saturated at 19 o, 50 C. contains 10*50 c.c. 2V> 

 per litre. 



Depth of Layer 



below surface. 1. 2. 



1 to 100 mm 10-57 8*01 



1500 to 1600 „ 8*91 4-08 



Before aeration 1*58 1*56 



