490 



SCIENTIFIC KECORD FOR 1883. 



twenty to twenty-five days earlier than at Vienna, and at Paris nine days- 

 earlier, but at Lemsberg sixteen days later, and Zlozow twenty-one 

 days later. On the plateau of the Harz Mountains the retardation is 

 thirty-four days, and the same also at Moscow. In the Alps, at 40i° 

 north latitude, 1700 meters altitude, the retardation is forty-five days, 

 or the same as at St. Petersburg. It is, however, p roper to consider such 

 phsenologie observations as illustrations of climatic characteristics rather 

 than as defining them." 



The following table gives for Vienna some of the preceding additional 

 climatic characteristics. For want of space Hann omits the details or 

 wind direction : 



Table II. — Additional climatic elements for Vienna. 



Having, in his introduction, thus defined our general conception of 

 the range of climatology, Hann devotes 175 pages to a consideration 

 of the principal features of the earth's climate — first, as depending on 

 the solar radiation ; and, next, as modified by physical conditions, i. e., 

 moisture, altitude, distribution of land and water. This section of his 

 work constitutes a popular treatise on meteorology that is fit to form 

 a separate treatise, and is by far the best at present extant, the only 

 ones comparable for accuracy and clearness being that of Blanford in 

 The Indian Meteorologist's Vade-Mecum. 



The remaining 550 pages of Hann's treatise are devoted to the de- 

 scription of the special climatology of the zones and districts of the 

 earth, constituting a very complete climate-geography. Through the 

 whole volume are distributed occasional notes and pages dealing with 

 the causes of atmospheric phenomena, so that the work is an indis- 

 pensable and admirable preliminary to the study of, or development of, 

 a systematic treatise on philosophical, deductive, and mathematical 

 meteorology. 



