PHOTOGRAPHY IN ASTRONOMICAL RESEARCH. 181 



being done. Especially <1<) ^ve Avaiit more and hcttcr hooks, written 

 l>y the best men on each subject. The ori<i:inal memoii-, thoii<j^h it may 

 be the pro})er form of publication for tlie workers themselves, does 

 not satisfy all re({uirements. There is much to be done in the way of 

 extension and collation before the work can be [)resented in a form 

 attractive to those who would o^ladly keep in touch with it if the 

 process could be made a little easier. Huxley was constantly urging 

 scientific men that it Avas not sufficient to attain results; they nnist 

 also express them in an intelligible and attractive form. Of course 

 it is not eas}'^ for the same man to do both. There are few who could 

 have determined, like Schiaparelli, that the period of rotation of the 

 planet Mercury was eighty-eight days instead of one, but there are 

 fewer still Avho, after making the discovery, could have given the 

 beautiful lecture which he gave before the King of Italy, developing 

 fully in attractive detail the consequences of the discovery; and 3'et it 

 is i)robably true that many more could make, at any rate, an attempt 

 m this direction if adequate opportunity and inducement were pro- 

 \ided. Could not a part of the sums available for the endowment of 

 i-esearc-h be devoted to the endowment of text-books? It is, of course, 

 an inducement to write such a book that it is a good thing well done; 

 but in the case of a scientific worker this is scarcely sufficient, because 

 tht^ same could be said of his continuing his particular work. If we 

 ask him to pause and render the treasures he has collected accessible 

 to others there must be some additional inducement. Publishers are 

 not able to offer pecuniary encouragement, because books of the type 

 I have in mind would not api)eal to a very large public. But why 

 should they not be subsidized^ I do not think it need be a very 

 costly business, if the money were placed in the hands of a central 

 body to issue invitations for books to be written. An invitation 

 would be in itself a compliment, and the actual pecuniary value of 

 the inducement would shrink in importance, just as the actual amount 

 of gold in a medal awarded by one of our leading scientific societies 

 is not very seriously regarded. It may be objected that to ask the 

 best men to write text-books is to set them to inferior work, and so to 

 delay true scientific progress; but are we sure that the real march of 

 science is being delayed ? There are pauses in a journey which merely 

 waste time, but there are others without wdiich the whole journey 

 may be delayed or prevented, as when a man should neglect to rest 

 and feed the horse which carries him. 



But the development of photography has brought with it much 

 more than a recurrence of diffidence in some amateurs; it has fore- 

 shadowed a serious rearrangement of astronomical work generally— 

 a new division of labor and a new system of cooperation. To quote 

 one notable instance, a very small number of observatories could take 

 enough photographs to keep the whole world busy examining or meas- 



