, are being pulled for the moment towards one another by
the elasticity of the skin of the waist; and, as they are free in the
air to move as they will, this will cause the hinder one to hurry on,
and the more forward one to lag behind, so that unless they are all
exactly alike both in size and distance apart they will many of them
bounce together before long. You would expect when they hit one another
afterwards that they would join, but I shall be able to show you in a
moment that they do not; they act like two india-rubber balls, and
bounce away again. Now it is not difficult to see that if you have a
series of drops of different sizes and at irregular distances bouncing
against one another frequently, they will tend to separate and to fall,
as we have seen, on all parts of the paper down below. What did the
sealing-wax or the smoky flame do? and what can the musical sound do to
stop this from happening? Let me first take the sealing-wax. A piece of
sealing-wax rubbed on your coat is electrified, and will attract light
bits of paper up to it. The sealing-wax acts electrically on the
different water-drops, causing them to attract one another, feebly, it
is true, but with sufficient power where they meet to make them break
through the air-film between them and join. To show that this is no
fancy, I have now in front of the lantern two fountains of clean water
coming from separate bottles, and you can see that they bounce apart
perfectly (Fig. 44). To show that they do really bounce, I have coloured
the water in the two bottles differently. The sealing-wax is now in my
pocket; I shall retire to the other side of the room, and the instant it
appears the jets of water coalesce (Fig. 45). This may be repeated as
often as you like, and it never fails. These two bouncing jets are in
fact one of the most delicate tests for the presence of electricity that
exist. You are now able to understand the first experiment. The
separate drops which bounced away from one another, and scattered in all
directions, are unable to bounce when the sealing-wax is held up,
because of its electrical action. They therefore unite, and the result
is, that instead of a great number of little drops falling all over the
paper, the stream pours in a single line, and great drops, such as you
see in a thunder-storm, fall on the top of one another. There can be no
doubt that it is for this reason that the drops of rain in a
thunder-storm are so large. This