THE PROGRESSIVE DISCLOSURE OF THE ENTIRE 

 ATMOSPHERE OF THE SUN. 1 



[With 4 plates.] 



By Dr. H. Deslandres, Membre tic Vlnstitut. 



The sun, to which this conference is devoted, is a superb subject 

 for study. Everyone realizes more or less clearly that the destinies 

 of our earth are closely bound with those of the sun, and so we ought 

 to know its real nature, its total radiation, its variations — in a word, 

 its precise and complete action upon our globe. Face to face with 

 the sun, our dependence upon it is absolute, and was recently sum- 

 marized tersely by one of our French statesmen, now minister of 

 finance, from whom I had asked a special appropriation for solar 

 researches at the Observatory of Meudon, where I am director. At 

 first he refused, alleging the continuous increase in the public dis- 

 bursements. Then, as I insisted, he said, " Yes ; you are right ; the 

 sun is master of us all; we must do something." And so the Ob- 

 servatory at Meudon was enabled to add to its ordinary means an 

 amount, truly very small, but which came opportunely and aided 

 greatly in the prosecution of researches the results of which I now 

 present to you. 



The study of the sun to-day requires a costly installation, compli- 

 cated apparatus, and a personnel specially apt in physical as well as 

 in astronomical observations. Since the sun lights the entire globe 

 and ripens all our crops, it seems but natural that every man should 

 direct his energies to the study of the sun. And with this in mind I 

 proposed, some years since, to the Astronomical Society of France, 

 that there be enacted a special and universal tax, only one cent per 

 capita, for the study of the sun. This would have assured a continu- 

 ous record of the sun and its changes not yet realized and, accord- 

 ingly, a more profound knowledge of this star. But as our taxes are 



1 Discourse delivered in French at the Royal Institution of Great Britain on Friday, 

 .Tune 10, 1910. Translated by permission from the author's separate, printed by Royal 

 Institution of Great Britain, London. Published also in Nature, London, Vol. 85, Jan. 2G 

 and Feb. 2, 1911. 



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