ASTRONOMY AND METEOROLOGY. 383 



ing 50 per cent, for loss of light for two reflectors in the one case, and none 

 (?) in the other) would comprehend a sphere of about 4*24 diameter the 

 outer shell of which, T12 in thickness, being the province of the great instru- 

 ment alone. But let us reduce these proportions to sections of equal spaces, 

 that we may judge more accurately of the relative powers. Now the solid 

 contents of different spheres, we know, are in the ratio of the cubes of their 

 diameters. Hence, the comparative spheres, penetrated by the two instru- 

 ments referred to, should be 4'24 3 to 2 3 ; that is, as 9'5 to 1. Deducting, then, 

 from this vast grasp of space the inner sphere, capable of being explored by 

 other instruments, we find that, out of nearly ten sections of space reached by 

 this telescope, there are nearly nine sections which the six-feet speculum 

 may embrace as peculiarly its own ! 



What its revelations yet may prove, then, we can have no idea. Several 

 thousands of nebulae have been catalogued : the great reflector might add to 

 these tens of thousands more. But this, seeing how few nights in a year are 

 favorable for the highest powers, must be the work of years of perseverance. 

 It would be a worthy undertaking for the government of a great country, to 

 afford the means of multiplying such gigantic instruments. Application is to 

 be made, in this direction, for a six-feet reflector at the Cape of Good Hope, 

 for the examination of the heavens toward the southern pole. Lord Rosse, 

 with his usnal nobleness of liberality, will yield up his laboratory, machinery, 

 and men, to the service of government, and is willing, moreover, to give the 

 direction and guidance of his mastermind. "Will the British nation be con- 

 tent with a refusal ? 



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

 haps, apprehended by the now usual measurement not of distances in miles, 

 or minions of miles, or diameters of the earth's orbit, but of the progress of 

 light hi 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 M. Peters, a space betwixt us and the fixed stars of the small- 

 est magnitude, the sixth, ordinarily visible to the naked eye, of 130 years in 

 the flight of light. This information enables us, on the principles of sounding 

 the heavens, suggested 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 assume the fact, that if any other teles- 

 cope 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 nebulas exhibiting a mere speck of misty 

 luminosity, from the combined light perhaps of 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 probability that a 



