e in reality the
legs are moving backwards and forwards 128 times a second. By looking at
the fork or its shadow, you will therefore be able to tell whether the
light is keeping exact time with the vibrations, and therefore with the
water-drops.

Now the water is running, and you see all the separate drops apparently
stationary, strung like pearls or beads of silver upon an invisible wire
(_see_ Frontispiece). If I make the card turn ever so little more
slowly, then all the drops will appear to slowly march onwards, and what
is so beautiful,--but I am afraid few will see this,--each little drop
may be seen to gradually break off, pulling out a waist which becomes a
little drop, and then when the main drop is free it slowly oscillates,
becoming wide and long, or turning over and over, as it goes on its way.
If it so happens that a double or multiple jet is being produced, then
you can see the little drops moving up to one another, squeezing each
other where they meet and bouncing away again. Now the card is turning a
little too fast and the drops appear to be moving backwards, so that it
seems as if the water is coming up out of the tank on the floor, quietly
going over my head, down into the nozzle, and so back to the
water-supply of the place. Of course this is not happening at all, as
you know very well, and as you will see if I simply try and place my
finger between two of these drops. The splashing of the water in all
directions shows that it is not moving quite so quietly as it appears.
There is one more thing that I would mention about this experiment.
Every time that the flashing light gains or loses one complete flash,
upon the motion of the tuning-fork, it will appear to make one complete
oscillation, and the water-drops will appear to move back or on one
place.

I must now come to one of the most beautiful applications of these
musical jets to practical purposes which it is possible to imagine, and
what I shall now show are a few out of a great number of the experiments
of Mr. Chichester Bell, cousin of Mr. Graham Bell, the inventor of the
telephone.

To begin with I have a very small jet of water forced through the nozzle
at a great pressure, as you can see if I point it towards the ceiling,
as the water rises eight or ten feet. If I allow this stream of water to
fall upon an india-rubber sheet, stretched over the end of a tube as big
as my little finger, then the little sheet will be depressed by the
wat