It is then by the laws of gravitation, combined with those of the centrifugal force, that the real form of the earth must be shown. Newton and Gregory had such confidence in this theory that they did not hesitate to advance that experiments on weight were a surer means of knowing the form of the earth than any geographical measurement. Louis XIV. had signalized his reign by that meridian which was drawn through France: the illustrious Dominico Cassini had begun it with his son; and had, in 1701, drawn from the feet of the Pyrenees to the observatory a line as straight as it could be drawn, considering the almost insurmountable obstacles which the height of mountains, the changes of refraction in the air, and the altering of instruments were constantly opposing to the execution of so vast and delicate an undertaking; he had, in 1701, measured six degrees eighteen minutes of that meridian. But, from whatever cause the error might proceed, he had found the degrees towards Paris, that is towards the north, shorter than those towards the Pyrenees and the south. This measurement gave the lie both to the theory of Norwood and to the new theory of the earth flattened at the poles. Yet this new theory was beginning to be so generally received that the academy's secretary did not hesitate, in his history of 1701, to say that the new measurements made in France proved the earth to be a spheroid flattened at the poles. The truth was, that Dominico Cassini's measurement led to a conclusion directly opposite; but, as the figure of the earth had not yet become a question in France, no one at that time was at the trouble of combating this false conclusion. The degrees of the meridian from Collioure to Paris were believed to be exactly measured; and the pole, which from that measurement must necessarily be elongated, was believed to be flattened.