A modern astronomer of no mean celebrity has, even in the present day, endeavoured to rob Galileo of this staple article of his reputation. From a careless examination of the papers of our celebrated countryman, Thomas Harriot, which baron Zach had made in 1784, at Petworth, the seat of lord Egremont, this astronomer has asserted[10] that Harriot first observed the satellites of Jupiter on the 16th of January, 1610; and continued his observations till the 25th of February, 1612. Baron Zach adds the following extraordinary conclusion:--"Galileo pretends to have discovered them on the 7th of January, 1610; so that it is not improbable that Harriot was likewise the first discoverer of these attendants of Jupiter." In a communication which I received from Dr. Robertson, of Oxford, in 1822[11], he informed me that he had examined a class of Harriot's papers, entitled, "De Jovialibus Planetis;" and that it appears, from two pages of these papers, _that Harriot first observed Jupiter's satellites on the 17th of October_, 1610. These observations are accompanied with rough drawings of the positions of the satellites, and rough calculations of their periodical revolutions. My friend, professor Rigaud[12], who has very recently examined the Harriot MSS., has confirmed the accuracy of Dr. Robertson's observations, and has thus restored to Galileo the honour of being the first and the sole discoverer of these secondary planets. The great success which attended the first telescopic observations of Galileo, induced him to apply his best instruments to the other planets of our system. The attempts which had been made to deprive him of the honour of some of his discoveries, combined, probably, with a desire to repeat his observations with better telescopes, led him to announce his discoveries under the veil of an enigma; and to invite astronomers to declare, within a given time, if they had observed any new phenomena in the heavens. Before the close of 1610, Galileo excited the curiosity of astronomers, by the publication of his first enigma. Kepler and others tried in vain to decipher it; but in consequence of the emperor Rodolph requesting a solution of the puzzle, Galileo sent him the following clue:-- "Altissimam planetam tergeminam observavi." I have observed that the most remote planet is triple. In explaining more fully the nature of his observation, Galileo remarked that Saturn was not a single star, but three together, nearly touching one another: he described them as having no relative motion, and as having the form of three o's, namely, oOo, the central one being larger than those on each side of it. Although Galileo had announced that nothing new appeared in the other planets, yet he soon communicated to the world another discovery of no slight interest. The enigmatical letters in which it was concealed, formed the following sentence:-- "Cynthia figuras æmulatur mater Amorum." Venus rivals the phases of the moon.