dividuals who bore her sacred name, it was fortunate for science that it found a refuge in the minds of princes. Notwithstanding the reiterated logic of his philosophical professor at Padua, Cosmo de' Medici preferred the testimony of his senses to the syllogisms of his instructor. He observed the new planets several times, along with Galileo, at Pisa; and when he parted with him, he gave him a present worth more than 1000 florins, and concluded that liberal arrangement to which we have already referred.

As philosopher and principal mathematician to the grand duke of Tuscany, Galileo now took up his residence at Florence, with a salary of 1000 florins. No official duties, excepting that of lecturing occasionally to sovereign princes, were attached to this appointment; and it was expressly stipulated that he should enjoy the most perfect leisure to complete his treatises on the constitution of the universe, on mechanics, and on local motion. The resignation of his professorship at Padua, which necessarily followed his new appointment, created much dissatisfaction in that university: but though many of his former friends refused at first to hold any communication with him, this feeling gradually subsided; and the Venetian senate at last appreciated the views, as well as the powerful motives, which induced a stranger to accept of promotion in his native land.

While Galileo was enjoying the reward and the fame of his great discovery, a new species of enmity was roused against them. Simon Mayer, an astronomer of no character, pretended that he had discovered the satellites of Jupiter before Galileo, and that his first observation was made on the 29th of December, 1609. Other astronomers announced the discovery of new satellites : Scheiner reckoned five, Rheita nine, and others found even so many as twelve: these satellites, however, were found to be only fixed stars. The names of Vladislavian, Agrippine, Uranodavian, and Ferdinandotertian, which were hastily given to these common telescopic stars, soon disappeared from the page of science, and

even the splendid telescopes of modern times have not been able to add another gem to the diadem of Jupiter.

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 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†, 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, 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

Berlin Ephemeris, 1788.

Edin Phil. Journ. vol. vi. P. 313.

Life and Correspondence of Dr. Bradley. Oxford, 1832, p. 523.

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:

"Cynthiæ figuras æmulatur mater Amorum."

Venus rivals the phases of the moon.

Hitherto, Galileo had observed Venus when her disc was largely illuminated; but having directed his telescope to her when she was not far removed from the sun, he saw her in the form of a crescent, resembling exactly the moon at the same elongation from the sun. He continued to observe her night after night, during the whole time that she could be seen in the course of her revolution round the sun, and he found that she exhibited the very same phases which resulted from her motion round that luminary.

Galileo had long contemplated a visit to the metropolis of Italy, and he accordingly carried his intentions into effect in the early part of the year 1611. Here he was received with that distinction which was due to his

great talents and his extended reputation. Princes, cardinals, and prelates hastened to do him honour; and even those who discredited his discoveries, and dreaded their results, vied with the true friends of science in their anxiety to see the first wonder of the age.

In order to show the new celestial phenomena to his friends at Rome, Galileo took with him his best telescope; and as he had discovered the spots on the sun's surface in the month of March, 1611, he had the gratification of exhibiting this new wonder to his admiring disciples. He accordingly erected his telescope in the Quirinal garden, belonging to cardinal Bandini; and in April, 1611, he exhibited them to his friends in many of their most interesting variations. From their change of position on the sun's disc, Galileo at first inferred, either that the sun revolved about an axis; or that other planets, like Venus and Mercury, revolved so near the sun as to appear like black spots when they were opposite to his disc. Upon continuing his observations, however, he saw reason to abandon this last opinion. He found, that the spots must be in contact with the surface of the sun; that their figures were irregular; that they had different degrees of darkness; that one spot would often divide itself into three or four; that three or four spots would often unite themselves into one; and that all the spots revolved regularly with the sun, which appeared to complete its revolution in about twenty-eight days.

Previous to the invention of the telescope, spots had been more than once seen on the sun's disc with the unassisted eye. But even if these were of the same character as those which Galileo and others observed, we cannot consider them as anticipations of their discovery by the telescope. As the telescope was now in the possession of several astronomers, Galileo began to have many rivals in discovery; and it is now placed beyond the reach of doubt, that he was not the first discoverer of the solar spots. From the communication which I received from the late Dr. Robertson, of

Oxford*, it appears that Thomas Harriot had discovered the solar spots on or before the 8th of December, 1610. His manuscripts, in lord Egremont's possession, incontestably prove that his regular observations on the spots commenced on the 8th of December, 1610,―at least three months before Galileo discovered them; and that they were continued till the 18th of January, 1613. The observations which he has recorded are 199 in number; and the accounts of them are accompanied with rough drawings representing the number, position, and magnitude of the spots.T

Another candidate for the honour of discovering the spots of the sun, was John Fabricius, who undoubtedly saw them previous to June, 1611. The dedication of the work in which he has recorded his observation, bears the date of the 13th of June, 1611; and it is obvious, from the work itself, that he had seen the spots during the year 1610: but as there is no proof that he saw them before the 8th of December, 1610, and as it is probable that Harriot had seen them before that date, we are compelled to assign the priority of the discovery to our distinguished countryman.

The claim of Scheiner, professor of mathematics at Ingolstadt, is more intimately connected with the history of Galileo. This learned astronomer having, early in 1611, turned his telescope to the sun, necessarily discovered the spots which at that time covered his disc. Light flying clouds happened, at the time, to weaken the intensity of his light, so that he was able to show the spots to his pupils. These observations were not published till January, 1612; and they appeared in the form of three letters, addressed to Mark Velser, one of the magistrates of Augsburg, under the signature of Apelles post Tabulam. Scheiner, who, many years afterwards, published an elaborate work on the subject, adopted the same idea which had at first occurred to Galileo,- that

• See page 22.

Edin. Phil. Journ. 1822, vol. vi. p. 317.

Joh. Fabricii Phrysii de Maculis in Sole observatis, et apparente ea