May 9, 1913] 



SCIENCE 



693 



individuals or even of single nations. A 

 few examples may illustrate what has al- 

 ready been accomplished. First, and fore- 

 most, we have the great star catalogue, 

 initiated at an international congress 

 twenty-five years ago, when eighteen ob- 

 servatories combined to divide the work, 

 each taking a number of zones in the heav- 

 ens. 



The importance of this work will be 

 plain to every one, and we must regret that 

 it is still so far from being completed. 



As it is not my intention simply to point 

 out the merits of international work, but 

 also to point out its difficulties, a few words 

 may be said which are not intended as 

 criticism, but which may serve to point out 

 the weakness which arises when there is no 

 central authority which lives longer than 

 the single individual can expect to live. 



Pioneers will always be found to initiate 

 a work, but in time they die or retire from 

 office ; others take their places, and if these 

 become more interested in fresh problems, 

 the work suffers unless it is effectively im- 

 pressed on their attention by some perma- 

 nent body. Where to find such a central 

 body, whose main functions would be to 

 endow an undertaking with sufficient in- 

 ertia to carry it over periods in which the 

 work may seem to be a drudgery, is a 

 matter which deserves careful considera- 

 tion. 



The completion of the "Star Cata- 

 logue," which has given rise to these re- 

 marks, is only the beginning of an even 

 greater piece of work. When we have 

 determined the positions and magnitude of 

 stars at any one time, we have only taken 

 the first step towards solving the main 

 problem, and must proceed to measure the 

 proper motions, the parallaxes, and also 

 map the spectra. This work is so vast that 

 aU hope to accomplish it within reasonable 

 limits is difficult and has to be abandoned 



unless our statistical ambitions are low- 

 ered, and instead of taking the complete 

 sphere of the heavens we select restricted 

 but typical areas for detailed examination. 

 This has been done on the initiative of 

 Professor Kapteyn, who has secured a suffi- 

 cient number of voluntary associates who 

 are now carrying out a combined under- 

 taking which has already yielded results 

 of the greatest importance, and you will 

 hear something more of this work from his 

 own lips. 



Now the essence of work of this kind 

 consists in shortening the time required to 

 accomplish an extensive task by dividing 

 it among a number of persons. If the 

 work is purely statistical it may be com- 

 plete in itself, and the published records 

 become then available to any one who re- 

 quires them. In other cases, the observa- 

 tions may have to be collected by a central 

 authority and treated by recognized meth- 

 ods of statistics or analysis before they 

 become useful to the scientific public. 

 While it is generally the observational por- 

 tion of the work that is subdivided and the 

 discussion that is centralized, the reverse is 

 the case in the proposal made by Professor 

 Pickering — that one central observatory in 

 a favorable position should furnish photo- 

 graphs in sufficient numbers and distribute 

 them among astronomers all over the 

 world, to be measured and discussed. 



Finally, a great undertaking of quite 

 a different character — the "International 

 CatalogTie of Scientific Literature" — must 

 be classed in the same category. This 

 catalogue has arisen out of a desire to 

 classify the scientific literature of the 

 world, so as to enable any one who desires 

 to study a certain subject to find out 

 quickly all previous researches relating to 

 it. Practically all nations in which scien- 

 tific work is carried out have united, each 



