The smallest natural Magnets generally possess the greatest proportion
of attractive power. Sir Isaac Newton wore in his ring a magnet which
weighed only three grains; yet it was able to take up 746 grains, or
nearly 250 times its own weight--whereas magnets weighing above two
pounds seldom lift more than five or six times their own weight.
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COAL GAS in BALLOONS.
Mr. Green has the merit of being the first person who made experiments
on the buoyant properties of Coal Gas. In some of his preliminary
trials, he ascertained that the ascensive force of a small balloon,
three feet in diameter, was equal to eleven ounces; but, when filled in
the old way, with hydrogen gas, not more than fifteen ounces.
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