Meanwhile the Plague broke out at Cambridge, making it necessary for him to retire into the country. It was in the garden of his country house that the fall of an apple is supposed to have suggested to Newton the theory of gravitation.
Scientists had for a long time been familiar with the fact that the earth is a colossal magnet, drawing everything upon its surface in the direction of its centre; but it was Newton who conceived the idea—and whether it was the falling apple that suggested it or no is unimportant—that the influence extended as far as the moon, and, if this could be established, to the stars throughout space. Was it not possible that the moon, trying to shoot off at a tangent, was continually pulled back by the earth, and so kept ‘falling’ round it? Newton tried experiments, applying laws already discovered, and found that the theory would not work. Undiscouraged he put the whole problem aside till more facts should have been discovered. It was not till 1682 that more accurate measurements of the earth gave Newton fresh data to go upon. Again he applied his theory, and this time he began to see that his problem was ‘coming out’—that the moon would fall just the right distance, 15 feet per minute. As he neared the end of his calculations he became so agitated that he could not go on: a friend had to finish it for him. And it was right. He had established the fact that not only is the moon subject to the law of gravitation, but that the whole universe is slung together in one stupendous system.
It is this grand discovery, and the wonderful invention of the calculus, that establish Newton’s claim to immortal honour. As says the inscription in Westminster Abbey: “The vigour of his mind was almost supernatural”.
Notes
In this précis the story should be condensed, and told as a continuous narrative, and not in scraps and jottings as in a log.
For the purpose of verifying positions, &c.—especially as the battle was fought at night—it is important to mention names of all ships.
It is also necessary to give the times of the chief events; but one can avoid monotony and scrappiness by using phrases such as “Ten minutes later.…”