Sxey,—On the Movements of Camphor on Water, 483 
Now, if the conclusions stated above are in the main correct, any 
substance floating upon a clear surface of water and discharging oil thereon, 
should describe motion, and motion of the same character as that which you 
have seen camphor make, Well, this is, I find, precisely what does happen 
when the experiment is performed, 
I rub this small piece of cork with a very little turpentine oil; it has 
now absorbed this oil, and appears but little different from another piece of 
cork I have here, which has not been oiled, I place both upon water, and 
now you can see that while the clean piece of cork remains stationary 
thereon, the oiled piece moves about in a very vigorous and eccentric 
manner, imitating the motion of camphor so closely that, except for the 
difference which exists between the colour of the two (the camphor and the 
cork), one would take them as they move for the same thing, 
Like effects follow when any non-volatile oil is used in place of turpen- 
tine. These experiments are surely crucial tests as regards the correctness 
or otherwise of the theory I have proposed to you. 
I will only add to this by stating that, should further research prove 
that the several deductions I have here made to you are correct, a decisive 
blow has been given to the popular theory that vapours are directly repellent, 
as they are emitted in presence of air, from substances at the same tem- 
perature and pressure as that of their surroundings*; and also, as I believe, 
to the theory that a repulsive property is innate in our oils, and that it is, as 
it were, developed into action whenever water is placed nearly in contact 
with them. I say nearly in contact, for the contact which ensues on collision 
of bodies may also cause repulsion, but not repulsion in the sense I use it 
here, viz., that in which it is used and to which it is limited by physicists 
when they deal with this particular matter. 
In this connection I cannot refrain from stating to you my belief that 
repulsion and its correlative attraction, whether in reference to electricity, 
magnetism, or the movements of masses in relation to each other, are not 
direct results indicating the action of two properties, but are secondary ones 
brought about by and indicating modification of matter. 
Postscript. 
I have lately been successful in getting results which, in the first place, 
demonstrate that the surface of water is chemically affected by camphor, and, 
in the second place, I got results which completely explodes the current idea 
that vapours in their emission drive solids away from them, as per se. 
I. Water which has had camphor moving over its surface a long time, 
refuses to gyrate camphor; its surface acquires a somewhat 
resinous lustre, being, in fact, more refractive of light than 
* Vapours, of course, are always in a repellent condition as they rush into a vacuum, 
