272 HISTORY OF ASTRONOMY. 



of the telescope. This mode lias the advantage of a 

 ready reference to the larger instrument, but is somewhat 

 inconvenient from the interference* of the stand in ob- 

 serving the space beneath the pole and near the 

 meridian. 



Three comets have been independently discovered by 

 Mr. Yan Arsdale, viz., one November 25, 1853, another 

 June 24, 1854, and a third September 13, 1854. The 

 first of these was not seen in Europe until December 2, 

 a week after it was discovered by Mr. Yan Arsdale; 

 the second was discovered in Europe June 4 ; the third 

 was discovered at Berlin, September 12. These dis- 

 coveries were made while searching for comets, although 

 the search was not thorough, as the view near the 

 horizon is obstructed by buildings, and the examination 

 was seldom continued to a late hour. 



SHELBY COLLEGE OBSERVATORY. 



A very superior telescope was ordered in 1848 from 

 the establishment of Merz and Mahler, of Munich, for 

 the use of Shelby College, Shelbyville, Kentucky. It 

 has an aperture of seven and a half inches, and a focal 

 length of ten feet. The mounting is admirably exe- 

 cuted, and differs in some respects from any other in 

 this country. It is furnished with a filar and an annular 

 micrometer. The filar micrometer has six positive eye- 

 pieces, with powers from 100 to 570. There are also 5 

 negative eye-pieces, magnifying from 102 to 550 times. 

 The hour circle is 10 inches in diameter, reading to 4 



