could have a position micrometer as well. 176 She used this instrument for 

 observations of comets, planets, and double stars, and made it available to 

 the astronomy students at Vassar College (q.v.). It is now in the Maria 

 Mitchell Observatory on Nantucket, along with the Clark telescopes 

 given by Mrs. Abbey and Miss Loines (qq.v. ) . 



Another Clark instrument known only from one slight 19th-century 

 reference is a 6^4 -inch refracting telescope owned by Moore of Lynn 

 (Massachusetts ?) by 1877. 177 



The Morrison Observatory was founded in 1875 and, until 1922, 

 was affiliated with the Pritchett School Institute of Glasgow, Missouri; it 

 has since been transferred to Central College at Fayette, Missouri, 

 (qq.v.). The large equatorial refractor of this observatory was made by 

 the Clarks. 178 This instrument, with an objective of 12*4 inches aperture 

 and 17 feet focus, was provided with graduated hour and declination 

 circles read by verniers, a clock drive regulated by a conical pendulum, 

 and a filar micrometer of which either the field or the wires could be 

 illuminated. Its cost, in the shop, was $6,000 in gold. With this telescope 

 Alvan Graham discovered a close companion to the star 78 Pegasi; 179 

 in 1878 Carr Waller Pritchett and his son Henry discovered and studied 

 the great Jovian red spot. When the telescope was completed George and 

 Alvan Graham went west to mount it; and two years later George went 

 again to Glasgow to help mount their new English transit instrument. 



The Morrison Observatory has three other Clark instruments — a 

 chronograph and two 4-inch aperture portable refractors. One of the 

 small telescopes is dated 1880 and was acquired by the observatory at 

 that time. It came complete with case for "ready and safe transporta- 

 tion," and was used especially on expeditions to observe transits and 

 eclipses. It was furnished with a ring micrometer and comet and solar 

 eyepieces, as well as a battery of common ones. Its mount, held on a 

 heavy walnut tripod, could be adjusted for either equatorial or altazimuth 



176 Maria Mitchell to William C. Bond, 15 January 1859 (letter in Bond Papers, 

 Harvard University Archives). 



177 "Size of the Principal Telescopes in the World," Popular Science Monthly, vol. 10 

 (1876-1877), p. 576. 



11 * Publications, Morrison Observatory, vol. 1 (1887), pp. 5-8. 



179 Alvan Clark to Edward S. Hoi den, 8 March 1876 (letter in Lick Observatory 

 Archives) . 



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