386 HISTOEY OF ASTRONOMY. 



Walker, and by Professor Kendall, at the Philadelphia 

 High School, and elicited high approbation. In 1849, 

 Mr. Fitz completed a telescope of 6f inches aperture for 

 ihe use of the Chilian expedition, and this was the 

 first telescope composed of proper crown and flint discs, 

 all his previous telescopes having been made of French 

 mirror plate convex lenses, instead of the superior op- 

 tical crown, of which he was hitherto ignorant. Since 

 1849, Mr. Fitz has been continually increasing the size 

 of his object-glasses, until he has at last attained to the 

 dimensions of the largest instruments furnished by 

 Merz and Mahler, of Munich. We shall enumerate the 

 principal telescopes which have been furnished by Mr. 

 Fitz, commencing with those of the largest size. 



No. 1 has a clear aperture of 12| inches, and a focal 

 length of 17 feet. It has 7 negative and 6 positive eye- 

 pieces, the highest magnifying power being 1200. The 

 decimation circle is 20 inches in diameter, graduated to 

 20', and reads by four verniers to 20". The right ascen- 

 sion circle is 20 inches in diameter, graduated to 20', 

 and reads by two verniers to two seconds of time. The 

 telescope is moved by clock-work, and is furnished with 

 a micrometer. This telescope was sold to the Michigan 

 University for $6000. Dr. Briinnow, the director of the 

 Michigan observatory, pronounces this telescope to be a 

 good one, and says that it compares favorably with the 

 Munich instruments of large size. The six stars in the 

 trapezium of Orion are visible without difficulty, and 

 Enceladus appears well at all times. The discs of the 



