ed by a vast number of little birds. The veracious
chronicler who escaped from a cloud of mosquitoes by crawling into an
immense metal pot and then amused himself by clinching the antennae of
the insects which bored through the pot until, to his horror, they
became so numerous as to fly off with the covering, was more scientific
than he supposed. Yes, a sufficient number of humming-birds, if we
could combine their forces, would carry an aerial excursion party of
human beings through the air. If the watch-maker can make a machine
which will fly through the room with a button, then, by combining ten
thousand such machines he may be able to carry a man. But how shall the
combined forces be applied?

The difficulties I have pointed out apply only to the flying-machine
properly so-called, and not to the dirigible balloon or airship. It is
of interest to notice that the law is reversed in the case of a body
which is not supported by the resistance of a fluid in which it is
immersed, but floats in it, the ship or balloon, for example. When we
double the linear dimensions of a steamship in all its parts, we
increase not only her weight but her floating power, her carrying
capacity, and her engine capacity eightfold. But the resistance which
she meets with when passing through the water at a given speed is only
multiplied four times. Hence, the larger we build the steamship the
more economical the application of the power necessary to drive it at a
given speed. It is this law which has brought the great increase in the
size of ocean steamers in recent times. The proportionately diminishing
resistance which, in the flying-machine, represents the floating power
is, in the ship, something to be overcome. Thus there is a complete
reversal of the law in its practical application to the two cases.

The balloon is in the same class with the ship. Practical difficulties
aside, the larger it is built the more effective it will be, and the
more advantageous will be the ratio of the power which is necessary to
drive it to the resistance to be overcome.

If, therefore, we are ever to have aerial navigation with our present
knowledge of natural capabilities, it is to the airship floating in the
air, rather than the flying-machine resting on the air, to which we are
to look. In the light of the law which I have laid down, the subject,
while not at all promising, seems worthy of more attention than it has
received. It is not at all unlikely