233 
HYDEOaENIUM. 
13Y EGBERT [HUNT, F.E.S. 
HE attention of experimental philosophers has, for some 
time past, been gradually drawn to the phenomena pre- 
sented by the operation of some obscure force, or forces, ever 
active in the molecular interstices of matter. Under a variety of 
terms they have been explaining, or rather endeavouring to 
explain, peculiar attractions manifested by the surfaces of bodies, 
and assuming different conditions, according to the peculiarities 
belonging to the surfaces under examination. The force known 
as capillary attraction — whether exhibited in tubes or between 
plates of glass — is tolerably familiar to all, and the mechanical 
power shown by the fibre-tubes of cotton will have been tested 
by almost every intelligent schoolboy. The absorption of water 
by a lump of sugar or of chalk, and the sucking up ” of water 
by a sponge, is so common, that few stop to ask by what power 
the phenomenon is brought about. We are now, however, 
beginning to discover that, in these, apparently, simple things, 
we may observe the opening of a door, disclosing a way, which 
promises to lead us to a knowledge of nature’s most secret 
operations. The simple adhesion of water to a perfectly 
clean plate of glass, informs us, that a power resides on that 
surface ; and, if we bring two such surfaces near together 
with a fluid between them, we see that the fluid is lifted 
against the gravitating influence of the whole Earth. In this 
we have hitherto detected a simple mechanical force only. Of 
late, however, M. E. Becquerel has informed us that this surface 
force has a power equal to the breaking up of strong chemical 
affinities. That, metallic solutions being employed, the metal is 
gradually separated from the solution and deposited in thin 
films upon the glass plates. In the fine fissures of green-stone 
rocks we often find films of native copper; and the films of gold 
in the cracks of the gold-bearing quartz are well known to the 
miner. These are doubtless due to the force resident on the 
surfaces of the rocks, in the same way as it is shown in action 
in M. E. Becquerel’s experiment. 
