20 PHENOMENA OF THE MIXTURE OF TWO 



liquids goes on through the substance of the blad- 

 der ; in the first experiment colourless water passes 

 from the tube c to the coloured brine in the tube 

 a b ; in the second, colourless brine passes from the 

 tube a b to the coloured water in the tube c. 



It is obvious, that the brine in the tube a b, 

 which is in contact with the bladder, becomes 

 diluted by the addition of water from the tube c ; 

 but this diluted brine is specifically lighter than 

 the original brine which is below it, and remains 

 therefore floating at its surface. 



On the other hand, the water in the tube c, when 

 mixed with brine from the tube a b, becomes 

 heavier than the pure water, and rests therefore on 

 the upper surface of the bladder, or that which is 

 turned towards the water. 



Hence it follows, that from the moment when 

 these two strata have been formed above and below 

 the bladder, neither concentrated brine nor pure 

 water comes any longer in contact with the bladder. 



From the bladder downwards in the tube a b are 

 strata of liquid, containing successively more salt ; 

 from the bladder upwards in the tube c are strata 

 containing successively more water. 



In the beginning of this experiment we observe, 

 that the volume of the water and of the brine 

 changes in both tubes ; the liquid in the limb b 

 rises from 1 to 2 lines ; but as soon as the strata 

 above mentioned have been distinctly formed above 

 and below the bladder, hardly any further rise is 



