METEOROLOGY. 



44a 



noon and midnight by an interval, often considerable, and in like manner 

 that the hottest and coldest days in the year follow midsummer and 

 midwinter by an interval often of many days, Dr. Haughton saw in 

 these facts a close analogy with the diurnal tides, which follow the sun 

 or moon's meridian passage by an interval of some hours. 



Using Ferrel's temperature tables. Dr. Haughton finds the following- 

 maximum secular ranges of mean annual temperature for the respect- 

 ive zones around the whole earth : 



Maximum secular ranges. 



This table shows that the average maximum effect of the astronomical 

 causes involved in perihelion longitude can never exceed 5° F. in the 

 northern hemisphere, and barelj' exceeds 1° F. in the southern. The 

 observed great ranges of climate between the Carboniferous and the 

 Glacial epochs therefore required some other elucidation. {Nature^. 

 XXIV, p. 93.) 



At the Cincinnati meeting of the American Association for the Ad- 

 vancement of Science, held in August, 1881, Mr. W. J. McKee read a 

 paper on a contribution to Croll's theory of secular climatic changes. 



Mr. Frederick Chambers summarizes the sun-spot studies of Charles 

 Chambers, Brown, Hill, Archibald, Blanford, and Mildrum, and con- 

 cludes that the relations with terrestrial meteorology must be studied in 

 greater detail — which work he has himself undertaken. Commencing 

 with the daily abnormal barometric variations observed at several 

 stations in Western India, it was soon found that, as the time over 

 which an abnormal barometric fluctuation extended became longer and 

 longer, the range of the fluctuation became more and more uniform at 

 the various stations, thus leading to the conclusion that the abnormal 

 variations of long duration afi'ect a very wide area. To test this infer- 

 ence it became necessary to compare the observations recorded at Bom- 

 bay with those of some distant tropical station. Batavia was chosen, 

 and, on plotting the daily observations side by side with those of Bom- 

 bay, the degree of accordance between them was found to be truly 

 surprising considering how far the two stations are apart. The monthly 

 abnormal variations were then jilotted and smoothed down bj' taking 

 nine months' means. The curves obtained in this way for Bombay and 

 Batavia were then found to be almost identical in form, but with this 



