AMERICAN INSTITUTE. 413 



great Architect of the skies to permit him to place his telescope on his 

 namesake, additional revelations would be impressed upon his telescopic 

 sphere, garnished with suns and starry configurations, marvellous as those 

 we now behold to-night. 



Watson followed, and his telescopes, in composition, polish, and figure, 

 were truly exquisite. His largest did not exceed nine inches aperture, but 

 they were never equalled before him. 



Tully was contemporary to Watson, though his telescopes were superior 

 to Short's, they were inferior to Watson's. 



Kamage, in 1820, constructed a telescope 15 inches in diameter and 25 

 feet focal length, which remained for many years in the Royal Observatory 

 at Greenwich, where its performances were ridiculed. It is now in the 

 Observatory of Glasgow. 



Lord Oxmantown's telescope has overcome many of Herschel's difficul- 

 ties, and carried to an extent he did not dare contemplate the illuminating 

 power, together with a sharpness of definition, little, if at all, inferior to 

 that of the achromatic. The moon's appearance, through his instrument, 

 was magnificent beyond expression. 



In 1853, an immense telescope was constructed in England, under the 

 supervision of M. Gavatt. The tube was 76 feet long, slung at the side of 

 a brick tower 64 feet high, and 15 feet in diameter. It resembles a cigar, 

 with the eye-piece at the narrow end, and a dew cap at the other; making 

 the total length, when in use, 85 feet. The design of the dew cap is to 

 prevent obscuration by the condensation of moisture, which takes place 

 during night when the instrument is in use. The exterior is of bright 

 metal, while the interior is black. The tube, at its greatest circumference, 

 measures 13 feet, and this part is 24 feet from the object glass. The opti- 

 cal works and the object glasses were executed by Slater. Two glasses 

 are used, one of flint and the other plate. The plate glass lens has a posi- 

 tive focal length of 30 feet IJ- inches ; the flint glass lens has a negative 

 focal length of 49 feet lO., inches. These two lenses placed in contact, are 

 used in combination, and constitute the achromatic object of glass. The 

 magnifying powers of this instrument range from five hundred to three 

 .thousand. A letter a quarter of an inch high can be read at a distance of 

 half a mile ; still its performances in that year were confused and un- 

 satisfactory. 



But of all the telescopes ever invented, the world-renowned Lord Rosse's 

 possesses peculiar qualities of superiority, which enable those having ac- 

 cess to it to collect light, and penetrate into regions of previously unknown 

 space. It enters into indefinite nebulous forms, which can only be ob- 

 served generally by other instruments, and exhibits wonderful configura- 

 tions altogether unimagined before — actually converting what we consider 

 nebulous fields of light, into superb clusters of stars. And it promises to 

 be of immense importance in reference to the dynamical principles on which 

 remote suns are sustained, while whirling about within their respective 



