Anomalies of Mean Annual Temperature Variation. 487 



in groups, in which the especial values are proportional to 

 the atomic number. Thus the relation between the different 

 groups, on the other hand, appears slightly more complicated. 

 3 The elements H-N, O-P, S-Or, Mn and Fe, Co and Ni, 

 Cu-Pd seem to form fairly well-marked groups. A new 

 group seems to begin at Ag; the elements Pt-Pb seem to 

 belong to a special group, which also seems to be the case 

 with the element U. In order to try to determine whether 

 the atomic absorption coefficient even under other experi- 

 mental conditions, may be arranged into the same groups, 

 especially at a radiation more homogeneous than that used 

 here, and also with rays of differing hardness, the experiments 

 will be continued. 



Stockholm, Nobel Institution 

 for Physical Chemistry. 



XLYI. Normal Anomalies of the Mean Annual Temperature 

 Variation. By Henrys: Arctowski*. 



r|^HB curves representing annual variations of atmospheric 

 JL temperature are generally derived from monthly means. 

 For many stations, belonging to different climates, these 

 curves convey the impression of representing a cyclic va- 

 riation, reflecting, with different amplitudes and more or 

 less retardation, the seasonal changes of solar declination. 



If, in the case of long series of observations, instead of 

 monthly means, the averages for each day of the year are 

 taken into consideration, the diagrams thus obtained display 

 most remarkable anomalies. As typical examples I would 

 refer to the curves of Koenigsberg, Munich, Catania, and 

 Valentia, published by Van Rijckevorsel f, and to the curve 

 derived from observations made in Melbourne, published by 

 R. J. A. Barnard %. Because of its simplicity, the Melbourne 

 curve may be taken as a demonstrative example of the pro- 

 blem in view. 



From the highest mean temperature, observed in January, 

 the means decrease more or less regularly till the middle of 

 March ; then, suddenly, temperature increases about 2° F. 

 Another characteristic break occurs between June 15th and 

 20th. After the minimum of July the increase of tempe- 

 rature is again interrupted in September and also at the end 

 of November. 



* Communicated by the Author. 



t Phil. Mag. ser. 5, vol. xlv. p. 459 (1898). 



% Phil. Mag. ser. 5, vol. 1. p. 408 (1900). 



