April 13, 1900.] 



SCIENGil 



579 



the Storia Celeste * and it is safe to say that 

 they will number 150,000. There are in the 

 catalogue 7646 stars and in the Storia Celeste 

 216 more which had been discarded. 



At the very beginning of the work the 

 CO- operation of Professor Porro of Turin 

 was secured. Some years ago he had be- 

 gun, while assistant to Professor Schiapar- 

 elli at Milan, an investigation of the inde- 

 pendence of the observations on the transit 

 instrument. By reason of his interest in 

 that question and the work already done in 

 connection therewith, he very readily con- 

 sented to become responsible for the reduc- 

 tion of all the observations of the transit in- 

 strument while the writer assumed respon- 

 sibility for all the observations on the Me- 

 ridian Circle and the rest of the new reduc- 

 tion. 



For the reduction of these latter 120,000 

 observations the work naturally is divided 

 into parts depending on the process to be 

 perfoi'med. The computation sheets for 

 each process have been designated respect- 

 ively as Form A, Form B, etc. The num- 

 ber of pages in each Form range from 386 

 to 8000 and are 8| by 11 inches in size. 

 There are already printed and partly or 

 wholly filled 22,.500 such pages in the fol- 

 lowing Forms : 



A. Jonrnal of Notes, constants, methods, etc. ? fo 



B. Day-book and provisional reduction to 1800 10 fc 



C. Besselian Star-constants for 1800 100 % 



D. Tabulated values of the star-eoustants .... 100 % 



E. Interpolated values of the day-numbers. .100 % 



F. Eeduction from Apparent to Mean place . . .40 fc 

 H. Compilation of positions by other observers 



for deduction of proper motions 10 % 



M. Miscellaneous tables and short computations ? fo 

 The percentage at the end of each line 

 shows approximately the amount which is 

 already accomplished. By very careful 

 methods of checking endeavor is made to 

 avoid numerical incorrectness, and though 

 the work is being pushed with all energy 



■* Nine volumes published by I.ittrow at Vienna, 

 1845-49. 



possible, it is not being done in haste at the 

 expense of accuracy. 



It is a pleasure to record the zeal with 

 which co-operation has been secured along 

 several lines not strictly included in the 

 direct opei-ation of newly reducing Piazzi's 

 observations, though vitally connected there- 

 with. Are-observation of all Piazzi's stars 

 for especial use in determining their proper 

 motions has been undertaken (and is already 

 far on its way towards completion) by Pro- 

 fessor J. G. Porter of the Cincinnati Obser- 

 vatory and Professor R. H. Tucker of the 

 Lick Observatoi-y. Miss Flora E. Harp- 

 ham and Professor Susan J. Cunningham 

 are performing all the labor of compiling 

 the star positions from other catalogues 

 for deduction of proper motions. Others 

 are doing other useful parts of the reduc- 

 tions and checkings. 



So long ago as 1866, when writing the 

 preface to his own reduction of D'Agelet's 

 observations, Dr. B. A. Gould made the fol- 

 lowing statement : 



"In addition to the motives already mentioned as 

 having prompted me to undertake this reduction and 

 catalogue, an especial incentive was found in the ex- 

 perience vrhiob it would afford and make available 

 foT a much more extended work which has long been 

 a cherished project, a recomputation of Piazzi's ob- 

 servations and the formation from them of a new 

 catalogue. This is an enterprise far too extensive 

 for the powers of a private individual, hut I look for- 

 ward with much hopefulness to the possibility of ob- 

 taining the requisite means at some future time . . . 

 No astronomical labor promises richer usefulness than 

 this ; and if the great work of reducing anew the 

 observations of Bradley be carried out bj' a combina- 

 tion of the astronomers of Europe, as is now proposed, 

 nothing seems more appropriate for the astronomers 

 of the New World than to render a similar service by 

 a new reduction of the Storia Celeste." 



This statement is even more true now 

 than when first written. Not alone have 

 the observations of Bradley been newly 

 reduced by Professor Arthur Auwers and 

 published twelve years ago, but a new re- 

 duction of Mayer's catalogue was pub- 



