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starch solution, alcohol, &c., seem to have little or no power 
of destroying the motion ; and the extraordinaiy properties 
of gum arabic have been noticed. I think it not unlikely 
that when these phenomena are fully investigated they 
will give strong support to a theory lately put forward by 
M. Becquerel, that the movements of fluids in animals and 
plants, which have often been attributed by Graham and 
others to osmose, are really due to minute electric currents. 
Mr. Dancer, F.R.A.S., stated, that the subject which Pro- 
fessor Jevons brought before the meeting, was one to which 
he had paid attention at intervals for the last thirty years. 
He had repeated Dr. Robert Brown’s experiments with the 
majority of the substances named in his paper, and had also 
experimented with a great number of other substances and 
different solutions. 
The particles approaching a spherical form gave evidence 
of the greatest activity, with some few exceptions. The 
activity and duration of the movements vary according to 
their magnitude and also the solution in which they are 
suspended. For instance some of the metallic oxides would 
exhibit the movement for some time, and then gradually get 
aground on the glass plate, and cease to move. There was 
some difficulty in reducing metals to particles sufficiently 
small and regular in form, for the exhibition of the 
molecular movement ; even hardened steel, when rubbed on 
a very fine hone, appears fibrous, and soft metals such as 
platinum and copper, like shavings, under a high magnifying 
power. Those siliceous particles of the hone which have 
their lines of cleavage favourably situated are frequently 
detached in thin plates during the act of grinding and form 
