618 



SCIENCE. 



[N. S. Vol. XVIII. No. 463. 



there must be others to obtain the neees- 

 saiy observations in those favored regions 

 of our planet in which the maximum of 

 sunshine can be depended upon. 



The then astronomer royal, Sir George 

 Airy, was most sympathetic, and as a re- 

 sult of this state action, the little observa- 

 toiy at South Kensington was shortly 

 afterwards enlarged; it has considerablj' 

 grown since then, but it is still in the ex- 

 perimental stage. Although, perhaps, I 

 am not the one to say it, I am prepared to 

 take the responsibility of stating that it 

 is now one of the best equipped for its 

 special work in the world. It certainly is 

 the shabbiest to look at. Irreverent com- 

 parisons have been made even in the House 

 of Commons ; the general appearance of its 

 wood and canvas huts having been likened 

 to that of a more or less disreputable look- 

 ing traveling menagerie, but, at all events, 

 it is instnunentally efficient, and that for 

 the present must be sufficient. 



During the last quarter of a century a 

 gi'eat deal of work has been going on, and 

 the colonies and dependencies of Britain 

 have also been doing yeoman service; very 

 little has been said about it, because not aU 

 departments are in the habit of advertising 

 themselves, and Blue Books are not as a 

 rule light reading. In the first place, the 

 Indian daily photographic record, which 

 was weak during a month or two during 

 the S.W. monsoon, was supplemented by 

 the erection of a duplicate instrument at 

 the Mauritius ; and I am again thankful to 

 say that the work has gone on at the Mauri- 

 tius continuouslj' since. Thus we have now 

 two tropical records, which, taken together, 

 may be described as absolutely continuous, 

 of solar changes sent to us in the most 

 imperial fashion by two observatories. An- 

 other appeal was made to Australia. For 

 a time records were sent us, but I am sorry 

 to say that after a time they ceased. 



These records are sent regularity with 



every precaution against loss, to the obser- 

 vatory at South Kensington ; and for the 

 days when no photographs have been taken 

 at Greenwich the necessary photographs 

 are transmitted there, where they are re- 

 duced in continuation of the record com- 

 menced in 1873 there, in succession to Kew. 



What has been the result of this? The 

 late astronomer royal took up this work at 

 Greenwich in 1873. In 1874, 1875, 1876, 

 1877, 1878, the average number of days on 

 which it was possible to obtain photographs 

 in each year was a little over 160, the exact 

 figures being 159, 161, 167, 171, 149. This 

 was Greenwich working alone, national 

 work. 



Next, we come to the imperial work. 

 Selecting years at random, and dealing with 

 1889 to 1893, I find that we obtained pho- 

 tographs of the sun in 1889 for every day 

 in the year except five, in 1890, for every 

 day except four, in 1891, for every day 

 except two. It is easy to understand that 

 with such a magnificentlj' complete record 

 as this the study of solar physics was enor- 

 mously improved. 



Very fortunately for science, even before 

 these steps were being taken to secure a 

 continuous record of the spotted area, Pro- 

 fessor Respighi (1869) and Professor 

 Tacchini (1872) had commenced at Rome 

 a daily record of the solar prominences and 

 of the latitudes at which thej' appeared at 

 different times. 



I pass on to some of the most important 

 work done during the last quarter of a 

 century, only referring to the results ob- 

 tained which bear upon the connection be- 

 tween solar and terrestrial changes. 



Many important advances were made in 

 1878. 



Mr. F. Chambers, in continuing his 

 studies on the Indian barometer, found* 

 a remarkable degree of resemblance in the 

 progression of barometric pressure during 



* feature, Vol. XVIII., p. 56T. 



