were then postponed till 1620, and in 1630 entirely given up.[1] Now (August, 1636,) as he heard that the Dutch merchants had even offered a premium of thirty thousand scudi to any one who should invent a sure method of taking longitudes at sea, he ventured, without the knowledge of the Inquisition, to offer his invention to the Protestant States-General. Diodati at Paris was the mediator in these secret and ceremonious negotiations. On 11th November, Galileo's offer was entertained in the most flattering manner in the Assembly of the States-General, and a commission was appointed, consisting of the four savans, Realius, Hortensius, Blavius, and Golius, to examine into the subject and report upon it.[2]
While Galileo was impatiently waiting for the decision that was never come to, he made his last great telescopic discovery, although suffering much in his eyes, that of the libration and titubation of the moon, about which he wrote his remarkable letter to Alfonso Antonini, bearing the signal date: "Delia mia carcere di Arcetri li 10 febbrajo 1637."[3]
The complaint in Galileo's eyes grew rapidly worse. By the end of June the sight of the right eye was gone, and that of the other diminished with frightful rapidity from a constant discharge.[4] But in spite of this heavy calamity, combined with his other sufferings, his interest in science did not diminish for a moment. Even at this sad time we find him carrying on a brisk correspondence with the learned men of Germany, Holland, France, and Italy, continuing his negotiations with the States-General with great zest,[5] as well as occupying himself perpetually with astro-
