Sharp was not only a most careful and indefatigable calculator, he was what was even more essential for Flamsteed--a most skilful instrument-maker; and he divided for him a new mural arc of 140° and seven feet radius, with which he commenced operations on December 12, 1689. Above all, Sharp became his faithful and devoted friend and adherent, and no doubt his sympathy strengthened Flamsteed to endure the trouble which was at hand. That trouble began in 1694, when Newton visited the Royal Observatory. At that time Flamsteed, though he had done so much, had published nothing, and Newton, who had made his discovery of the laws of gravitation some few years before, was then employed in deducing from them a complete theory of the moon's motion. This work was one of absolutely first importance. In the first place and chiefly, upon the success with which it could be carried out, depended undoubtedly the acceptance of the greatest discovery which has yet been made in physical science. Secondarily--and this should, and no doubt did, appeal to Flamsteed--the perfecting of our knowledge of the movements of the moon was a primary part of the very work which he was commissioned to do as Astronomer Royal. Newton was, therefore, anxious beyond everything to receive the best possible observations of the moon's places, and he came to Flamsteed, as to the man from whom he had a right to expect to receive a supply of them. At first Flamsteed seems to have given these as fully as he was able; but it is evident that Newton chafed at the necessity for these frequent applications to Flamsteed, and to the constant need of putting pressure upon him. Flamsteed, on the other hand, as clearly evidently resented this continual demand. Feeling, as he keenly did, that, though he had been named Astronomer Royal, he had been left practically entirely without support; his instruments were entirely his own, either made or purchased by himself; his nominal salary of £100 was difficult to get, and did not nearly cover the actual current expenses of his position, he not unnaturally regarded his observations as his own exclusive property. He had a most natural dislike for his observations to be published, except after such reduction as he himself had carried through, and in the manner which he himself had chosen. The idea which was ever before him was that of carrying out a single great work that should not only be a monument to his own industry and skill, but should also raise the name of England amongst scientific nations. He complained of it, therefore, both as a personal wrong and an injury to the country when some observations of Cassini's were combined with some observations of his own in order to deduce a better orbit for a comet.