According to Olbers, a concave and convex lens were first used in combination, to render objects less distant in appearance, in the year 1606. In that year the children of one Jean Lippershey, an optician of Middelburg, in Zealand, were playing with his lenses, and happened to hold one before the other to look at a distant clock. Their great surprise in seeing how near it seemed attracted their father's attention, and he made several experiments with them, at last fixing them as in the modern telescope--in draw tubes. On the 2nd of October, 1606, he made a petition to the States-General of Holland for a patent. The aldermen, however, saw no advantage in it, as you could only look with one eye instead of two. They refused the patent, and though the discovery was soon found of value, Lippershey reaped no benefit. Galileo was the first to apply the telescope to astronomical observations. He did not have it made in Holland, but constructed it himself on Lippershey's principle. This was in 1609. Its magnifying power was at first 4, and he afterwards increased it to 7, and then to 30. With this he discovered the phases of Venus, the spots on the sun, the four satellites of Jupiter, and the mountains of the moon. [Illustration: PLATE X.--THE DISCOVERY OF THE TELESCOPE.] Kepler, in 1611, made the first astronomical telescope with two concave glasses. Huyghens increased the magnifying power successively to 48, 50, and 92, and discovered Saturn's ring and his satellite No. 4. Cassini, the first director of the Paris Observatory, brought it to 150, aided by Auzout Campani of Rome, and Rives of London. He observed the rotation of Jupiter (1665), that of Venus and Mars (1666), the fifth and third satellites of Saturn (1671), and afterwards the two nearer ones (1684); the other satellites of this planet were discovered, the sixth and seventh, by Sir William Herschel (1789), and the eighth by Bond and Lasel (1848). We may add here that the satellites of Uranus were discovered, six by Herschel from 1790 to 1794, and two by Lassel in 1851, the latter also discovering Neptune's satellite in 1847. The rotation of Saturn was discovered by Herschel in 1789, and that of Mercury by Schroeter in 1800. The earliest telescopes which were reflectors were made by Gregory in 1663 and Newton in 1672. The greatest instruments of our century are that of Herschel, which magnifies 3,000 times, and Lord Rosse's, magnifying 6,000 times, the Foucault telescope at Marseilles, of 4,000, the reflector at Melbourne, of 7,000, and the Newall refractor. [Illustration: PLATE XI.--THE FOUNDATION OF PARIS OBSERVATORY.]