Any ordinary young man would not have found anything very interesting in that, but to Galileo the observation was a kind of revelation. He thought that if he could work out a machine driven by swinging weights, such a machine could be made to go quite steadily, and could be made into a clock which would show the time accurately. He did contrive a kind of counting machine by means of a pendulum which would count its own swings, but he did not succeed in making a clock that would keep going any length of time. He designed a clock which could be wound up and driven by means of a weight, but this was not done until he was very old and blind, and he could only dictate the description of the clock to his son, and the latter did not succeed in constructing the clock until ten years after his father’s death. Nevertheless Galileo must be regarded as the inventor of the pendulum clock. In the year 1609 a rumour reached Galileo which started him on an entirely new line of discovery. He had heard that a Dutch optician had presented to a German prince an instrument constructed in such a manner that objects which were distant could be seen as if they were near. A letter which he received from Paris confirmed the news, but could not give him any information as to how the instrument was constructed. Galileo thought about this discovery for a whole night, and in the morning he had found out the secret of it. He took two lenses, one of them a magnifying glass, and the other a glass which made things smaller. The magnifying glass he fixed at one end of a leaden pipe, and at the other end he fixed the other glass. This end he held to his eye, and the other end he directed towards a distant object. At first he saw nothing, but on moving the magnifying glass to and fro along the pipe, he found the position in which distant objects appeared magnified to three times the ordinary size. He straightway set to work to improve the instrument, and in a short time he succeeded in constructing a telescope which brought objects thirty times nearer and magnified their surface a thousand times. [Illustration: Fig. 26.--A modern Astronomical Telescope.] Galileo went to Venice and showed it to the chiefs of the Republic. He took them up to the highest church tower in the city, and mounted his telescope so as to look out to sea. He said, “Many noblemen and senators, although of great age, mounted the steps of the highest church towers at Venice to watch the ships, which were visible through my glass two hours before they were seen entering the harbour.” This remarkable invention made Galileo world-famous. The kings, princes, and learned men of the world all wanted telescopes, and asked Galileo to make them. Such requests even came from Holland, where the principle of the telescope had first been discovered.