The Rutherfurd Photographic Measures. 159 



Reference Books— (See Table XXIII.) 



(1.) Bessel — Astronomische Nachrichten, No. 365-6, and Vol. 

 XVII. 



(2.) Peters — Recherches sur la Parallaxe des Etoiles Fixes. 

 Recueil de Memoires presentes a V Academie des Sciences par 

 les Astronomes de Poulkova. Vol. I, page 136. 



(3.) Struve — Nouvelle Determination de la Parallaxe an- 

 nuelle des Etoiles a Lyrse et 61 Cygni. Memoires de 1' Academie 

 Imperiale des Sciences de St.-Petersbourg, VII Serie. Vol. I, 

 No. 1 , page 44. 



(4.) Auwers — TTntersuchungen iiber die Beobachtungen von 

 Bessel und Schliiter am Konigsberger Heliometer zur Bestim- 

 mnng der Parallaxe von 61 Cygni. Abhandlungen der Academie 

 zu Berlin, 1868 : page 113. 



(5.) Socoloff — Parallaxes des Etoiles observees par G-. 

 Schweizer. Annales de P Observatoire de Moscou, Vol. VIII, 2, 

 pages 89-90. 



(6.) Lamp — Neue Berechnung der Parallaxe von 61 Cygni aus 

 den Beobachtungen von Schweizer in Moskau 1 863-1 866, Kiel, 

 1883, pages 52-9. 



(1.) Johnson — Introduction to the Observations with the 

 Heliometer. Part II of Astronomical Observations made at the 

 Radcliffe Observatory in the year 1853. "Vol. XIV, page xxxix. 



(8.) Ball — On a new Determination of the Parallax of the 

 Preceding Star of 61 Cygni by the Method of Differences of 

 Declination. Astronomical Observations and Researches made 

 at Dunsink. Part III, page 27. 



(9.) Ball — Further Researches on the Parallax of 61 Cygni. 

 Astronomical Observations and Researches made at Dunsink. 

 Part V, page 166. 



(10.) Belopolsky — Astronomische Nachrichten, No. 2888. 



These values of parallax are computed from discordances in right ascension 

 between observations made six months apart on the transit instrument by 

 Wagner at Poulkova in 1862-1870. 



(11.) Hall — Observations for Stellar Parallax. Washington 

 Observations for 1883, Appendix II, pages 54 and 67. 



