Botany and Zoology. 405 
pairs of stars were stern alternately on different threads, the 
hose of 
zeros determined under the same circumstances as t the 
coe the position iil easured by turning the circle 
in ways. From four to six measures of p and s were made 
each’ siotit and for each pair of the brighter stars at least four 
nights observations were made, i. e., at least sixteen measures of 
pands. The reductions are complete, and the observations are 
reduced oe 1870 0. 
§ 4 deals with the accuracy re the observations ; for the brighter 
stars, the probable error of a si. ngle observation is found to 
in 8, “0"228, in p (reduced) +0":306. The probable errors for 
within less than 1” in each coérdinate, which Dr. Vogel considers 
sufficient for his purpos 
§5 treats of the determinations of the brightness of the star. 
of this cluster. ptt a stars of the cluster range between the 
6°5 and Ae ma 
ined by ave estimates of itude 5 times; the pro 
able error of the mean is +0714 eerie * the brighter stars 
were determined on several evenings e, and on two 
‘§ 6 gives the srl of the stars (in tabular <a ed wig 
Results, A difference eniehon the Spring and Aut serva 
tions, in Both Aw and Ad, of one of the stars indicates vas peaeivty a 
parallax of about 07:3. 
§7 gives the Observations of the Fundamental Stars ; and Cat- 
alogue of the 30 brightest stars. The observations are of relative 
Aa and Ad of the four sage stars, and of two of Arge- 
lander’s stars in A Perseé and also meridian observations. These 
last also iididate a nb to cand star 6. None of the stars 
appear to have a large proper motio 
8 deals in the sane ray with Oheeoattorl of the fainter stars ; 
and Catalogue of all the stars of the cluster. "This is followed by 
two charts, one of the brighter stars and the plan of triangulation, 
the other of the whole cluster. 
AM. Jour, $c1,—Tuirp — Vou. XV, No. 89.—May, 1878. 
