440 ASTROPHYSICS 



lately for that very important body of astronomers who are some- 

 times called amateurs, though the name is open to criticism, - - those 

 whose opportunities for work are restricted to a more or less limited 

 leisure. It is a body which is somewhat sensitive to the feeling that 

 astronomical work has gone beyond them, that in the presence of 

 large instruments and of the special knowledge acquired by those 

 using them, their own efforts and their own humbler instruments are 

 no longer of any value. If I am right in supposing that this feeling 

 has been called into existence lately by the rapid advances made in 

 photography, it is certainly not for the first time. At previous epochs 

 this diffidence has found expression, and has, I am glad to say, been 

 met by careful contradiction; but it is necessary to repeat the ex- 

 postulation again and again, for the anxiety is apt to crop up with 

 every new development of astronomical activity. 



The early days of photography were better ones than usual for 

 the amateur; indeed, the introduction of the photographic method 

 is largely due to the work of such men as Rutherfurd and Draper 

 in America, de la Rue and Common in England. But now that we 

 have passed beyond the stage when each new plate taken was a 

 revelation; now that we are tolerably familiar, at any rate, with 

 the main types of possible photographs which can be taken with 

 modest apparatus; more especially now that we have begun to 

 discuss in elaborate detail the measurement of star-positions or of 

 stellar spectra, the old shyness is beginning to crop up again. But 

 it is of the utmost importance that this shyness should be zealously 

 overcome. Perhaps, after all, it is not sufficient to assert that there 

 is still good work for amateurs to do, nor even to mention a few 

 instances of such work urgently required; perhaps it should be 

 made easier for them to follow what is being done. Especially do 

 we want more and better books, written by the best men in each 

 subject. The original memoir, though it may be the proper form 

 of publication for the workers themselves, does not satisfy all re- 

 quirements. There is much to be done in the way of extension and 

 collation before the work can be presented in a form attractive to 

 those who would gladly keep in touch with it if the process could be 

 made a little easier. Huxley was constantly urging upon scientific 

 men that it was not sufficient to attain results; they must also ex- 

 press them in an intelligible and attractive form. Of course it is not 

 easy 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 who, 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 yet it is 

 probably true that many more could make, at any rate, an attempt 



