Newton had issued a pamphlet with diagrams showing how to study light, and the apparatus was so simple and cheap that the "Newton experiments" were tried everywhere in schoolrooms.
People always combat a new idea when first presented, and so Newton found himself overwhelmed with correspondence.
Cheap arguments were fired into Cambridge in volleys. These were backed up by quibbling men—Pro Bono Publico, Veritas and Old Subscriber—men incapable of following Newton's scientific mind. In his great good-nature and patience Newton replied to his opponents at length.
His explanations were construed into proof that he was not sure of his ground. One man challenged him to debate the matter publicly, and we hear of his going up to London, king that he was, to argue with a commoner.
Such terms as "falsifier," "upstart," "pretender," were freely used, and poor Newton for a time was almost in despair.
He had thought that the world was anxious for truth! Some of his fellow-professors now touched their foreheads and shook their heads ominously as he passed. He had gone so far beyond them that the cries of "whoa!" were unnoticed.
It is here worth noting that the universal fame of Sir Isaac Newton was brought about by his rancorous enemies, and not by his loving friends. Gentle, honest, simple and direct as was his nature, he experienced notoriety before he knew fame.
To the world at large he was a "wizard" and a "juggler" before he was acknowledged a teacher of truth—a man of science.
When the dust of conflict concerning Newton's announcement of the qualities of light had somewhat subsided, he turned to his former discovery, the Law of Gravitation, and bent his mighty mind upon it. The influence of the moon upon the Earth, the tilt of the Earth, the flattening of the poles, the recurring tides, the size, weight and distance of the planets, now occupied Newton's attention. And to study these phenomena properly, he had to construct special and peculiar apparatus.
In Sixteen Hundred Eighty-seven the results of his discoveries were brought together in one great book, the "Principia." Newton was forty-five years old then.