148 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 70 



Berlin, St. Petersburg, Fritsch (1854) came to the conclusion that 

 the temperature during increase of sun spots fell off yearly about 

 0.5° C. and vice versa, increased to that amount with decreasing 

 sun spot activity. R. Wolf came to similar results in the year 1859 

 by the investigation of the temperature series at Berlin, and Zim- 

 mermann also from the Hamburg observations. 



The most thorough investigations of recent times are those of 

 W. Koppen published in the year 1873. He used observations at 

 403 stations which he divided into 25 regions distributed over the 

 whole earth, and which he separated into five climatic zones. He 

 reached the conclusion that the heat maximum in the tropics is 

 from a half year to one and a half years (on the average nine- 

 tenths year) before the corresponding sun spot minimum, and more 

 retarded the further one goes from the equator. The temperature 

 minimum in the tropics occurs about the time of sun spot maximum. 

 The temperature variations show themselves most regularly and 

 distinctly in the tropics with an average amplitude of 0.73° C, fall- 

 ing off in magnitude towards the poles. The temperature amplitude 

 at the investigated stations outside the tropics had an average value 

 of 0.54° C. 



Koppen found besides that the agreement between temperature 

 variations and sun spot variations is not always the same. While 

 the temperature curve in the period from 1816 to 1859 followed 

 closely the inverted sun spot curve, before and after this time, there 

 was only a slight degree of correspondence. By later investiga- 

 tions in the year 1881 Koppen found that disagreements between the 

 two curves lasted from 1859 to 1875. 



Schuster (1885) came to the same conclusion as Koppen. R. Wolf 

 advanced the view (Astr. Mitt. XXXIV) that in the year 1859 the 

 sun spot curve quite radically changed its form, and together with 

 it also the curve of the variation of the magnetic declination. Blan- 

 ford (1891) found, however, that for the later times there is a good 

 agreement between both curves as shown by the collection of numer- 

 ous observations for India and he concluded therefrom that the 

 earlier found disagreement after i860 depended mainly on lack of 

 exact observations. 



Blanford published also (1891) a series of temperature measure- 

 ments which were taken by Prof. Hill with the solar thermometer, 

 that is, the black bulb and vacuum thermometer, for the years 1875 

 to 1885 in Allahabad. The measured mean value for the year varied 

 oppositely as the sun spot numbers and was 3.7° C. (6.6° F.) higher 

 at sun spot minimum than at maximum. 



