892 



SCIENCE. 



[N. S. Vol. XIV. No. 362. 



cations begun by the University of Pennsylvania 

 for the new Flower Observatory, which was for- 

 mally inaugurated with a public address by 

 Professor Simon Newcomb in November, 1897. 

 The Flower Observatory is widely known among 

 astronomers as a new institution managed on a 

 solid conservative basis, by a gifted and devoted 

 staff of untiring workers. Though it has been 

 in operation but a few years, it has already 

 taken its place among the leading observatories 

 of the country. It is distinguished by the care 

 and accuracy of all its work rather than by the 

 quantity of material turned out ; and for that 

 reason it has from the start taken rank with the 

 best of modern observatories. The care and 

 painstaking accuracy which characterized Pro- 

 fessor C. L. Doolittle's work at the Sayre 

 Observatory in Bethlehem, Pa., was at once 

 recognizable in the spirit of the new institution 

 under his direction at Philadelphia ; and the 

 results are now becoming apparent in the first 

 volume of the 'Publications.' 



Part II. of this volume appeared more than 

 a year ago, and dealt in a characteristically 

 thorough manner with the variations of lati- 

 tude observed at Philadelphia, and with sev- 

 eral determinations of the constant of aber- 

 ration incidentally made in connection with the 

 latitude work. This constant came out some- 

 what larger than the value which had gener- 

 ally been used by astronomers. The value 

 found by Struve and Peters at Poulkowa was 

 20^^.44, and for many years this was accepted 

 as standard ; but recent investigations by sev- 

 eral authorities tend to increase the figure to 

 about 20^^.55, which is the value found by Pro- 

 fessor Asaph Hall, Jr., at the Detroit Observa- 

 tory of the University of Michigan. Professor 

 C. L. Doolittle's several determinations con- 

 firm this larger value ; and on account of the 

 care and precautions exercised in the work, 

 there is little doubt in the minds of conserva- 

 tive astronomers that this new figure is much 

 nearer the truth than that adopted in the 

 nautical almanacs. 



Part III. of Volume I. of the New Publica- 

 tions is devoted to the measures of 900 double 

 and multiple stars made with the 18-inch 

 Brashear refractor of the Flower Observatory, 

 by Professor Eric Doolittle, son of the director 



of the Observatory. This part consists of 146 

 large quarto pages of closely set matter, all 

 beautifully and conveniently arranged. There 

 is no defect in the conception or execution of 

 the work, and it is not too much to say that 

 this publication may be taken as a model for 

 astronomers generally. 



A concise introduction of eight pages deals 

 with the constants of the equatorial, and with 

 the micrometer employed in the measures. The 

 latter is an ordinary filar micrometer, with the 

 Burnham illumination. Its simplicity enabled 

 the observer to center his whole attention on 

 the work, and the result is a handsome volume 

 of measures on 900 double and multiple stars, 

 all made within the past four years. The stars 

 are chosen mostly from the lists of Burnham, 

 with occasional selections from the Struves and 

 Dewbowski, and such modern observers as 

 Hough and See. They represent in all cases 

 objects requiring measurements. Though no 

 special search was made for new double stars, 

 a list of 22 such objects found in the prosecu- 

 tion of the regular work is given on page 8 ; all 

 of them being close or interesting pairs which 

 should receive the attention of future observers. 

 The 900 stars measured are arranged in order 

 of right ascension, with places referred to 

 the epoch 1880.0. Their magnitudes and the 

 several designations used by astronomers are 

 clearly and accurately given in each case. The 

 measures are nicely reduced and annual means 

 are formed, according to the classic models of 

 the Struves, Dewbowski and Burnham, The 

 notes accompanying the measures are brief and 

 to the point ; no important matter is over- 

 looked, and yet nothing superfluous is ever 

 added. The total number of complete observa- 

 tions is about 3,700, representing something 

 like 44,000 settings of the micrometer. 



It should be pointed out that all these obser- 

 vations were taken and reduced by Professor 

 Eric Doolittle alone, in addition to his teaching 

 duties at the University, where he conducts ad- 

 vanced coursesof instruction in celestial mechan- 

 ics. In conclusion it may be noticed that pub- 

 lications dealing with the measurement of 

 double stars are not merely of contemporary in- 

 terest, but increase in value with time. Thus 

 the work of the Herschels, the Struves and 



