[21] Joh. Fabricii Phrysii de Maculis in Sole observatis, et apparente earum cum Sole conversione, Narratio. Wittemb. 1611. 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 _Appelles 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 the spots were the dark sides of planets revolving round and near the sun.[22] [22] It does not appear from the history of solar observations at what time, and by whom, coloured glasses were first introduced for permitting the eye to look at the sun with impunity. Fabricius was obviously quite ignorant of the use of coloured glasses. He observed the sun when he was in the horizon, and when his brilliancy was impaired by the interposition of thin clouds and floating vapours; and he advises those who may repeat his observations to admit at first to the eye a small portion of the sun's light, till it is gradually accustomed to its full splendour. When the sun's altitude became considerable, Fabricius gave up his observations, which he often continued so long that he was scarcely able, for two days together, to see objects with their usual distinctness. Fabricius speaks of observing the sun by admitting his rays through a small _hole_ into a dark room, and receiving his image on paper; but he says nothing about a lens or a telescope being applied to the hole; and he does not say that he saw the spots of the sun in this way. Harriot also viewed the solar spots when the sun was near the horizon, or was visible through "thick layer and thin cloudes," or through thin mist. On December 21, 1611, at a quarter past 2 P.M., he observed the spots when the sky was perfectly clear, but his "sight was after dim for an houre."