visit to our neighbour the moon. The poor attempts of the aeronaut have shewn the hoplessness of the enterprise. The success of his achievement depends on the buoyant power of the atmosphere, but the atmosphere extends only a few miles above the earth, and its action cannot reach beyond its own limits. The only machine, independent of the atmosphere, we can conceive of, would be one on the principle of the rocket. The rocket rises in the air, not from the resistance offered by the atmosphere to its fiery stream, but from the internal reaction. The velocity would, indeed, be greater in a vacuum than in the atmosphere, and could we dispense with the comfort of breathing air, we might, with such a machine, transcend the boundaries of our globe, and visit other orbs.
Instead, however, of torturing our imagination to conceive of a rocket device, which would eclipse the performances of all flying machines, let us take one of nature's rockets as the material aid to our imaginary flight. Let us follow the course of some comet in its wanderings across our system. A rocket, held fast, with its fiery stream directed against a strong wind, very well represents the telescopic appearance of a comet, when in the neighbourhood of the sun. The luminous particles shoot out from the nucleus of the comet, precisely as the sparks issue from the rocket-tube, and they are thrown back as a strong wind would throw back the fiery stream of the rocket.
