Photography at Greenwich Observatory. 13 



reductions of all the Greenwich, observations for nearly 100 

 years by the present Astronomer Royal, Mr. Airy, who has 

 himself compiled some excellent star catalogues, who has 

 planned instruments combining engineering and optical science 

 in a way previously unknown, who has introduced the gal- 

 vanic system for registering observations, and devised an 

 instrument especially devoted to making trustworthy observa- 

 tions of the moon in parts of her orbit inaccessible by meridian 

 instruments — an addition which has resulted in bringing up 

 the tables of the moon to a pitch of excellence apparently 

 leaving nothing to be desired. 



In carrying out the determination to adhere to the im- 

 provement of the fundamental data of astronomy in preference 

 to all other objects, the directors of our national observatory 

 have evinced the greatest self-denial, and have been compelled 

 to leave to other observatories or to private amateurs the 

 brilliant pursuit of new planets and comets, the attractive 

 subjects of double and variable stars, the glorious revelations 

 of spectrum analysis applied to the heavenly bodies, and even 

 the valuable aid of photography in delineating the features of 

 the sun and moon. There is, however, one application of 

 photography so thoroughly practical in its character that it 

 has been gladly taken advantage of at the Greenwich Observa- 

 tory, and it is of this interesting process that we now propose 

 to offer some particulars, assisted as we have been by the 

 materials kindly furnished by the Astronomer Royal. 



The photographic operations to which we allude are the pro- 

 cesses carried on for the continuous self-registration by photo- 

 graphy of the indications of the magnetic and meteorological 

 phenomena at Greenwich, which, although among the most 

 valuable of all applications of the beautiful art-science referred 

 to, is yet eminently unobtrusive in character, and for thousands 

 who admire the photographic delineations of the persons they 

 love or esteem, the exquisite scenery of our own or other lands, 

 or the glories of architecture, sculpture, or painting, we can 

 count but a few individuals who comprehend and appreciate 

 the ceaseless working of the photographic records of the mag- 

 netic and meteorological instruments at the observatories of 

 Greenwich, Kew, and Oxford; the daily portraiture of the 

 solar spots at Kew, Cranford, and Ely ; and the magnificent 

 delineations of the lunar disc and the phenomena of a total 

 solar eclipse, which Mr. De La Rue has produced; as well as 

 the occasional photographic operations of a few other followers 

 of astronomical or physical science. 



In utility it is probable that not one of these valuable 

 applications of photography will compare with this automatic 

 registration of phenomena, so delicate in their nature and so 



