484 SCIENTIFIC RECORD FOR 1883. 



Royal Prussian Meteorological Institution at Torgau, where lie had 

 been professor since 1840. In 1866 he was called to Berlin, and in 1874; 

 became Dove's assistant at the institute, since which time, both as an 

 assistant and during the past three years as temporary successor to 

 Dove, he conducted most of the work of that office. (Z. 0. G. M., xvn, 

 p. 489.) 



II. — GENERAL TREATISES. 



In general climatology the publication of Hann's Handbuch der KU- 

 matologie (Stuttgart, 1883, 8vo, pp. x + 764), marks an important epoch 

 by reason of the precision of thought and the exteDt and freshness of 

 the numerical data. Many of the author's views are worthy of wide 

 attention and adoption, and are therefore here reproduced as follows: 



"By climate we understand the sum total of the meteorological phe. 

 nomena that characterize the mean condition of the atmosphere at any 

 one place on the earth's surface. That which we call the weather is only 

 one phase, a single act, or part of the succession of phenomena whose 

 complete course, more or less uniform, year after year constitutes the 

 climate of any locality. The climate is the totality of the weather for 

 a longer or shorter portion of time, as it ordinarily occurs on the 

 average at this time of the year ; but we speak of the weather of a 

 special day or month or season j e. g., the climate of England is mild 

 and damp in December, although the weather of December, 1879, was 

 very cold. We never speak of the rainy climate of the summer of 1882 

 in Germany, but the rainy weather. The theory or philosophy of the 

 weather and of climate will therefore respectively treat of the daily 

 changes and the average condition of the atmosphere. 



"Meteorology includes both weather and climate, and shows the 

 causal dependence of these upon the fundamental simple principles of 

 physics. The principal climatic factors are temperature and moisture 

 of the air, rain or snowfall, force and direction of the wind, &c. Of 

 the^e the temperature is undoubtedly the most important, and not only 

 the temperature of the air itself as given by thermometers protected 

 from radiation, but equally so the temperature, or rather heat, due to 

 direct radiation of sun, air, and earth. This latter radiation is an 

 extremely variable quantity, even at one and the same locality, while 

 the air temperature proper is comparatively uniform over a large extent 

 of territory and time. 



"I. The elements of the air temperature that are most important for 

 the correct presentation of any climate are the following: 



" 1. The monthly and annual mean temperatures of the air. 



" 2. The magnitudes for each month of the daily variation of tem- 

 perature. 



" 3. The mean temperature for at least one early morning hour and 

 afternoon hour about the time of the lowest and highest temperatures, 

 and if possible also for a later hour in the evening. 



" 4. For long series of observations, the extreme limits between which 

 lie the mean temperatures of the individual months. 



