1888.] LH ffect of Surface Tension on Chemical Action. 265 
effect on the ultimate state of equilibrium, but if the surface tension 
affects that state it will also affect the rate at which the system 
approaches it; this is much more easily measured, and the follow- 
ing experiments were undertaken to see if any effect of the kind 
exists. The reactions on which the effects of surface tension were 
tried were the following. 
1. A solution of sugar acting upon one of permanganate of 
potash destroys the colour, and gives a reddish precipitate. 
2. <A solution of hyposulphite of soda acting upon one of 
bichromate of potash changes its colour, and gives a yellowish 
green precipitate. 
3. Peroxide of hydrogen bleaches aniline very slowly. 
4. It has the same effect upon eosine. 
5. And upon infusion of roses. 
6. Dilute nitric acid bleaches indigo solution. 
Method.—At first we attempted to form films that would hold 
the necessary salts in solution, but without success. Next ca- 
pillary tubes were tried, and lastly placing the liquid between 
sheets of glass. 
Moderately dilute solutions were mixed in a test-tube and 
surrounded with black velvet to exclude the light. By means 
of a pipette a little of the liquid was withdrawn and six drops 
placed in the centre of a sheet of perfectly clean and dry glass, 
over this another sheet was laid and the whole covered with black 
velvet. 
After a time, another equal quantity was withdrawn from the 
test-tube, and placed between sheets of glass as before, and the 
colour compared with the first. This process was continued until 
a very decided difference appeared between the first plates and 
the last. 
The surface tension was determined from time to time by 
measuring the height the liquid rose in a capillary tube. 
The changes in the density of the liquids were very small, 
less than one in four hundred, and not always of a nature to assist 
the capillary action, so that it is impossible to explain the results 
obtained by that means. 
