Curiosities of Science. 99 



closes, the satellites and belts and rings of Saturn, the old and new 

 ring, which is advancing with its crest of waters to the body of the 

 planet, the rocks, and mountains, and valleys, and extinct volcanoes 

 of the moon, the crescent of Venus, with its mountainous outline, 

 the systems of double and triple stars, the nebulae and starry clusters 

 of every variety of shape, and those spiral nebular formations which 

 baffle human compi-ehension, and constitute the greatest achievement 

 in modern discovery. 



The Astronomer Royal, Mr. Airy, alludes to the impression 

 made by the enormous light of the telescope, partly by the 

 modifications produced in the appearance of nebulae already 

 figured, partly by the great number of stars seen at a distance 

 from the Milky Way, and partly from the prodigious brilliancy 

 of Saturn. The account given by another astronomer of the 

 appearance of Jupiter was that it resembled a coach-lamp in 

 the telescope ; and this well expresses the blaze of light which 

 is seen in the instrument. 



The Rev. Dr. Scoresby thus records the results of his visits : 

 The range opened to us by the great telescope at Birr Castle is best, 

 perhaps, apprehended by the now usual measurement not of distances 

 in miles, or millions of miles, or diameters of the earth's orbit, but 

 of the progress of light in free space. The determination within, no 

 doubt, a small proportion of error of the parallax of a considerable 

 number of the fixed stars yields, according to Mr. Peters, a space be- 

 twixt us and the fixed stars of the smallest magnitude, the sixth, ordi- 

 narily visible to the naked eye, of 130 years in the flight of light. This 

 information enables us, on the principles of sounding the heavens, sug- 

 gested by Sir W. Herschel, with the photometrical researches on the 

 stars of Dr. Wollaston and others, to carry the estimation of distances, 

 and that by no means on vague assumption, to the limits of space 

 opened out by the most effective telescopes. And from the guidance 

 thus afforded us as to the comparative power of the six feet speculum 

 in the penetration of space as already elucidated, we might fairly as- 

 sume the fact, that if any other telescope now in use could follow the 

 sun if removed to the remotest visible position, or till its light would 

 require 10,000 years to reach us, the grand instrument at Parsonstown 

 would follow it so far that from 20,000 to 25,000 years would be spent in 

 the transmission of its light to the earth. But in the cases of clusters 

 of stars, and of nebulae exhibiting a mere speck of misty luminosity, 

 from the combined light of perhaps hundreds of thousands of suns, the 

 penetration into space, compared with the results of ordinary vision, 

 must be enormous ; so that it would not be difficult to show the proba- 

 bility that a million of years, in flight of light, would be requisite, in 

 regard to the most distant, to trace the enormous interval. 



GIGANTIC TELESCOPES PROPOSED. 



Hooke is said to have proposed the use of Telescopes having 

 a length of upwards of 10,000 feet (or nearly two miles), in 

 order to see animals in the moon ! an extravagant expectation 

 which Auzout considered it necessary to refute. The Capuchin 

 monk Schyrle von Rheita, who was well versed in optics, had 

 already spoken of the speedy practicability of constructing te- 



