XIII. — The Rutherfurd Photographic Measures of Sixty-two 



Stars about -q Gassiopeise^ 



BY HERMAN S. DAVIS, 

 Read April 1, 1895. 



As was stated in the paper on the Parallax of q Cassiopeitfi* 

 the conditions of exposnre and the methods of measurement of 

 the twenty-seven negatives of stars about q Cassiopeise made by 

 Rutherfurd between 30 July, 1870, and 21 December, 1873, are 

 exactly the same as in the case of a and Q Cassiopeitef , and, it 

 might also be added, the same as of the Pleiades plates. | In the 

 present paper I have, therefore, in the main, followed the methods 

 of reduction so fully set forth in the Pleiades publication. 



In Table I. are given the general data of exposure of the plates, 

 while in Table II. are the means of the refractions computed for 

 the Eastern and Western impressions§ with the data of Table I. 

 by the formul{e|| 



ZZl^ = X [tan-:cos-(p—q) + i] 

 s 



- — p = — ^;fCOsec i^tan-;^ sin 2 (j) — q) 



The argument for entering this table is p, which has been 

 printed in double columns to save the repetition of the numerical 

 values of the above equations in the succeeding columns since 

 they are the same whether the argument be jj or (p + 180°) ; in 

 all other respects the form of publication is similar to that used 



*Tlie Parallax of v Cassiopeite, deduced from Rutherfurd Photographic 

 Measures, by H. S. Davis. Annals N. Y. Acad, of Sci., Vol. VIII., Feb., 1895. 



fTlie Parallaxes of ,« aud H Cassiopeite, deduced from Eutherfurd Photo- 

 graphic Measures, by H. Jacohy. Annals N. Y. Acad, of Sci., Vol. VIII., 

 March 1893. 



tThe Rutherfurd Photographic Pleasures of the Group of the Pleiades, by H. 

 Jacohy. Annals N. Y. Acad, of Sci., Vol. VI., Feb. 1892. 



ilbid., p. 240. 



Illhid., pp. 253-259. 



ANJfALS N. Y. AcAD. Sci., VIII., June, 1895.— 27. 



