ANNIVERSARY ADDRESS. 1 1 



that a conference of Astronomers of various nations should be 

 invited to be held in Paris in the spring of this year with a view- 

 to taking concerted action for obtaining on a uniform plan a 

 complete map of the whole starry heavens. To attend this 

 Conference Mr. Russell left these shores early in March last. His 

 temporary absence from our meetings during the present session, 

 whilst the interesting papers he was wont to submit to the society 

 will be much missed, will, we may expect, be amply compensated 

 for by the abundance of new matter which he will acquire and be 

 able to afford us on his return. 



The application of photography to the delineation of celestial 

 objects has made such rapid strides of late years, that the question 

 is now seriously entertained whether it may not be trusted for the 

 formation of star maps and catalogues. It has been found that 

 by the power of photography objects altogether invisible to the 

 •eye through the most powerful telescopes have been revealed. It 

 was mentioned, as an instance at the meeting of the Royal Society 

 in November last, that one of the stars of the Pleiades was found 

 to be surrounded by a nebula, which could not be seen with 

 telescopes, the reason given being that with the eye an object is 

 either seen or not seen at once, whilst with the photographic plate 

 feebleness of intensity is made up for by length of exposure. Dr. 

 Gill, a Fellow of the Royal Society, is contemplating, if not 

 engaged at the present time at the Cape Observatory, in taking 

 photographs — so Professor Stokes tells us — of the whole starry 

 heavens of the Southern Hemisphere. The success of the Messrs. 

 Henry in their photograph of the Pleiades, suggested to them 

 that it was possible, to survey the entire heavens in the same 

 manner. Such a survey could not be carried out by any 

 single observatory, but by live or six acting in unison, it is believed 

 to be quite possible, before the close of the present century to 

 survey the entire heavens on a scale, which will give us the 

 positions and magnitudes of probably not fewer than twenty 

 millions of stars. Such a record of the heavens seemed a few 

 years ago to be entirely beyond our reach, but the discoveries by 



