and as it appeared to me that it depended upon the theory of perspective, I reflected on the manner of constructing it, in which I was at length so entirely successful that I made a spy-glass which far surpasses the report of the Flanders one. As the news had reached Venice that I had made such an instrument, six days ago I was summoned before their highnesses the signoria, and exhibited it to them, to the astonishment of the whole senate. Many noblemen and senators, although of a great age, mounted the steps of the highest church towers at Venice, in order to see sails and shipping that were so far off that it was two hours before they were seen steering full sail into the harbour without my spy-glass, for the effect of my instrument is such that it makes an object fifty miglia off appear as large and near as if it were only five."[1]
Galileo further relates in the same letter that he had presented one of his instruments to the senate, in return for which his professorship at Padua had been conferred on him for life, with an increase of salary to one thousand florins.[2]
On his return to Padua he became eagerly engrossed in telescopic observation of the heavens. The astonishing and sublime discoveries which were disclosed to him must in any case have possessed the deepest interest for the philosopher who was continually seeking to solve nature's problems, and were all the more so, since they contributed materially to confirm the Copernican theory.
His observations were first directed to the moon, and he discovered that its surface was mountainous, which showed at all events that the earth's satellite was something like the earth itself, and therefore by no means restored it to the aristocratic position in the universe from which it had been displaced by Copernicus. The milky way, as seen through the telescope, revealed an immense number of small stars. In Orion, instead of the seven heavenly bodies already known, five hundred new stars were seen; the number of the Pleiades, which had been fixed at seven, rose to thirty-six; the planets showed themselves as disks, while the fixed stars appeared as before, as mere bright specks in the firmament.
But the indefatigable observer's far most important dis-
