Presidknt's Address — 8ect. A. 23 



Sflunit and Fcteis were sulwcribecl to variable .star research, it was 

 understood that this was on their part an act of condescension. Witli 

 all these great astronomers variable star work was a side issue. 



In 1870 an American expedition was sent to Cordova, in the 

 Argentine Republic, to carry out a detailed survey of the s(juthern 

 sky. Fortunately for science the instruments and other accessories 

 of this expedition were delayed for over two years, and Dr. Gould, the 

 leader of the expedition, instead of spending the time in vain regrets, 

 straightway set about a naked eye examination of the visible southern 

 sky. He and his assistants had no other instruments than their eyes, 

 and they used them well. The magnitude or brightness of every star 

 visible in the southern sky was estimated with an accuracy which makes 

 the Uranometria Arfjendna, as the survey of the Cordova observers is 

 called, one of the epoch-making books in the history of astronoui}'. In 

 going over the stars one by one, variable after varialile was discovered, 

 for the southern sky was virgin field. 



The publication of the Uranometria Aryenthia in 1880 created a 

 new interest in \ariable star astronomy, and in Europe and America 

 the study was taken up with an earnestness which to this day has 

 suffered no ebb. Especially in America was this interest most evident. 

 Over all the States a body of amateurs, men whose names are now 

 commonplace in the histor}- of astronomj', entered upon the search 

 for new variable stars, while at Harvard Observatory variable star 

 work was made a special enterprise. The Harvard Observatory^ also 

 some ten years ago sent out an expedition to Areciuipa, Peru, to follow 

 up by photography the survey work begun by Dr. Gould. 



Finding in 1890 that the variable stars discovered by Dr. Gould 

 were left unwatched, 1 entered that year upon the pursuit that has 

 kept my few spare hours from being a tedious leisure. I was the sole 

 southern observer of variable stars until the arrival at the Cape, some 

 fourteen years ago, of Mr. R. T. A. Innes, now Transvaal Government 

 observer. His work on variable stars, a work also carried on in his 

 spare hours, has gained for this indefatigable and able observer an 

 honoured place among astronomers. 



It may indicate how the science has grown during the past twenty 

 years if I mention that when I began observing in 1890 only twenty 

 southern variable stars were known ; now, chiefly through the work 

 at the Cape, Arequipa and Harvard, the number is nearer five 

 hundred. 



The number of known variables all over the sky cannot at this 

 present date be far short of 2000 ; as many are being discovered now on 

 the average each week as were discovered in the whole lapse of time 

 prior to the nineteenth centurj'. 



We now approach the second section of our address, viz :^ 



Methods of Research. 



It would be entirely out of place ft)r me to seek in an address of 

 this character to deal exhaustively, or evgn fully, with the methods 



