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THE POSSIBILITIES OF THE TELESCOPE. 

 By A. B. Biggs. 



Up to about the end of the 15th century mankind was in 

 a condition of helpless ignorance with regard to the nature, 

 the distances, and the dimensions or (except two) the form 

 of the various bodies which constitute the visible universe. 

 No human eye had ever beheld either stars or planets as 

 other than dimensionless points. Their motions and posi- 

 tions had been carefully observed, systematised and theorised 

 upon ; but they were unapproachable. What a wonderful 

 revelation then must that have been which Galileo's telescope 

 opened up ! practically diminishing the distance some 20 or 

 30 times. True, his was a very simple affair, and feeble in its 

 infancy; but it revealed some most important facts. It 

 served to show that the planets at least were globes, some of 

 them of vast bulk : it opened up to human vision for the 

 first time the wonderful mountainous scenery of the Moon. 

 But perhaps its most important service was to establish 

 beyond question the Copernican theory of astronomy by 

 revealing the phases of the inner planets — also the moons of 

 Jupiter — a Copernican system in miniature. 



The Rings of Saturn constituted an inscrutable riddle, 

 reserved for further development of this new power of vision. 



Since Galileo's time, the effort has been constant and 

 unwearying to develop to the utmost the power of the 

 instrument. There were difficulties inseparable from the 

 principle on which the instrument is constructed, which it 

 was long thought never could be overcome, the chief of which 

 was (briefly stated) that a ray of light, when bent out of its 

 course, as by a prism, or a lens, is separated into its different 

 component colours, each having a different focus. The dis- 

 covery and utilisation of the fact that different kinds of 

 glass have different separating or prismatic effect, led to the 

 construction of the achromatic object glass. This gave a new 

 start to the powers of the instrument, so that we have 

 reached from Galileo's power of 30, and imperfect at that, to 

 a power o± about 3,000 in the Lick Telescope. 



Well, now the question arises : — If we have from the time 

 of Galileo been enabled by the gradual improvement of the 

 telescope to stretch our gaze farther and farther into space, 

 why should we not still go on enlarging its scope. As we 

 now see clearly the configuration of the lunar mountains, 

 why should we not, in time, come to see the trees growing 

 upon there sides, if there be any ? Why not discover signs of 

 organised existence, if such exist? Is there any limit to 



