492 PROCEEDINGS OF THE AMERICAN ACADEMY. 



stage of our knowledge of the atmosphere. It cannot well be other- 

 wise. But it leaves a great gap which no one man can ever fill, because 

 meteorology has now grown to such an extent that specialization is the 

 rule, and no single mind will ever again master all of its details. 

 Hann's "Lehrbuch der Meterologie " is the one absolutely indis- 

 pensable textbook in that science. Upon his " Handbuch der Klima- 

 tologie" all studies of climatology must, for years to come, be based. 

 This extraordinary grasp of the whole wide range of his science he 

 maintained practically till the day of his death. 



Somehow, when a man like this passes away, a bare statement of the 

 essential facts of his life and a list of his contributions to science seems 

 unnecessary and futile. Yet there is something singularly significant 

 in the fact that this man, living a very simple life, with very few 

 changes of residence, extended his interests and his reading to all parts 

 of the world. He knew the geographical and climatological conditions 

 of almost every corner of the globe as intimately as if he had himself 

 lived there. Hann — for thus, and not as von Hann, he will oftenest 

 be recalled — was born March 23, 1839, near Liuz, in Austria. He 

 began his professional life as a school-teacher. At the age of twenty- 

 nine he entered the Central-Anstalt fiir IVIeteorologie in Vienna. 

 From 1874 to 1897 he was its Director, an office from which he retired 

 at the age of fifty-eight. For many years he was a professor at the 

 University of Vienna, first of Physical Geography and later of Physics. 

 His work for meteorology did not cease when he ceased to be Director. 

 He went to Graz as Professor at the University, and there, in the 

 Physical Institute, he UTote liis "Lehrbuch der Meteorologie," whose 

 three editions bear the dates 1901, 1906, 1915. A fourth edition, 

 supervised by Siiring, is now in course of preparation. In 1900, Hann 

 returned to Vienna as Professor of Cosmical Physics, a position which 

 he held until his retirement in 1910. The " Handbuch der Klimatolo- 

 gie" he wrote while in Vienna. The three editions of this book bear 

 the dates 1883, 1897, 1908-1911. These two books are Hann's 

 monumental publications. It is almost literally true that no student 

 of meteorological science can do a day's work without referring to 

 them. Throughout his long editorship and joint editorship of the 

 Meteor ologische Zeitschrift (1866-1920) he steadily contributed to the 

 pages of that journal a series of articles and notes which are invaluable, 

 for in these he revised, summarized, commented upon, and put into 



