PEOCBBDIN G S 
OF THE 
MANCHESTER 
LITERARY AND PHILOSOPHICAL SOCIETY. 
Ordinary Meeting, October 4th, 1881. 
J. P. Joule, D.C.L., LL.D., F.R.S., &c., in the Chair. 
“On Drops Floating on the Surface of Water,” by Pro- 
fessor Osborne Reynolds, F.R.S. 
It is well known that under certain circumstances drops 
of water may be seen floating on the surface for some se- 
conds before they disappear. Sometimes during a shower 
of rain these drops are seen on the surface of a pond, they 
are also often seen at the bows of a boat when travelling 
sufficiently fast to throw up a spray. Attempts have been 
made to explain this phenomenon, but I am not aware of 
any experiments to determine the circumstances under 
which these drops are suspended. Having been deeply en- 
gaged in the experimental study of the phenomena of the 
surface tension of water and the effect of the scum formed 
by oil or other substances, it occurred to me that the com- 
parative rarity of these floating drops would be explained if 
it could be shown that they required a pure surface, a sur- 
face free from scum of any kind. For, owing to the high 
surface tension of pure water, its surface is rarely free from 
scum. The surface of stagnant water is practically never 
free except when the scum is driven off by wind. But 
almost any disturbance in the water, such as the motion of 
the point of a stick round and round in the water, or water 
Proceedings — Lit. & Phil, Soc. — Vol. XXL. — No, 1. — Session 1881-2. 
