connected with its Surface Tension. 155 
| Table III contains values of A at different temperatures for 
two liquids. The inferior limit of the radius of the sphere of 
action of a molecule obtained, which is equal to = is of the 
same order of magnitude as the usually accepted radius of a 
_ molecule. 
TABLE III. 
Ether. 
iio ay | | | 
1 te Ena A ne 
BEES EOGN NL T5°36 | Qe 10a’ can. | 1G 
333 BG-60 i) TOs als Tine 1-7 
353 | 37-43 | 65:85 | 42 - , 1-8 
Ba 3787 | 60:36 149... 1-8 
Carbon tetrachloride 
363 | 40:3 | 40-62 | 32x10 em.) 1-6 
383 | 41:39 | 38640 03-618 (aie sel rl 
403 49-33 | 3658 | 40 _,, ee | 
423 BO; GON DA AO NAC re, 1-9 
| | 
| 
| | : | 
The table also contains the values of the number of layers of 
molecules n, in a film of thickness A, which is given by 
a 
en (*) syle 
Mm 
The values are all less than 2, and a film therefore consists of 
a single layer of molecules when stretched out till its area is 
equal to A. Now the surface tension must obviously decrease 
before this stage is reached. Since », is calculated on the 
supposition that 7 oe 
follows therefore that the ratio 
dx 
ToT r 
on the average increases with a decrease of the thickness of film 
when it is less than that of twice the radius of the sphere of 
action of a molecule. 
is independent of the thickness of film, it 
