302 METEOROLOGY AND ALLIED SUBJECTS. 



quadrants — the greater the inequality the faster the movement. In the 

 North Atlantic Ocean this evaporation is largely dependent upon the 

 presence of open water or a covering of ice, whence he is led to con- 

 clude that the storm paths of this region may be classified in two 

 periods. The first is that of the frozen East Polar Sea, with floating 

 ice in the West Polar Sea, which period is marked by great frequency of 

 depressions over the Atlantic and their movement southward into the 

 interior of Eussia. The second period is that of the frozen West Polar 

 Sea, with less ice in the East Polar Sea, which period is marked by 

 fewer Atlantic cyclones, which all pass from the Gulf Stream into the 

 East Polar Sea. There is no regularity in the duration of these periods, 

 although there is some appearance as if the first belonged to the winter 

 and the second to the summer season. {Z. 0. G. 3L, XV, 1880, p. 217.) 



J. Elliott has published an elaborate report of the Madras cyclone. 

 May, 1877, in which he contributes much to the knowledge of the circum- 

 stances attending the inception of the cyclones of the Bay of Bengal. 

 He says that it is doubtful whether there is in all cases a single calm 

 center which continues unbroken during the continuance of the cyclonic 

 disturbance in its more intense form and the path of which marks the 

 line of advance of the cyclone. It is quite probable that, with the inter- 

 mittent actions of the winds, one of the commonest features of cyclones 

 being rapid variations in their intensity, which give rise to the well known 

 phenomena of squalls, there may be a continuous disappearance of one 

 storm center and the formation of another in its neighborhood. 



The only entirely new and adequate factor in the meteorological con- 

 ditions present during the origin and existence of this cyclone was rain- 

 fall; the cyclone gradually developed after the rainfall, and its intensity, 

 bears the most direct and marked relation to the intensity of the rainfall. 

 It followed the line of heavy rainfiill throughout its existence. 



The energy of the latent heat given out produces an ascensional or 

 expansional movement in the atmospheric condensing region, and this 

 disturbance is followed by an attempt towards equilibrium, which in 

 this case is the converging motion of the lower atmospheric strata to 

 the area of rainfall. {Z. 0. G. M., Vol. XV, 1880, p. 308.) 



Eagona has published a work on the general movement of the at- 

 mosphere, and the prediction of the weather in especial reference to 

 Italy. He states that the barometric depressions approaching Italy from 

 the northwest and south jiass around the peninsula rather than over it. 

 About the same number of depressions approach from all directions. 

 {Z. 0. G. M., XVI, 1881, p. 452.) 



Dr. Van Bebber has strdied the daily and monthly course of the 

 barometric minima in Europe, 1876-1880, and endeavored to contribute 

 toward bridging over the gap between climatological studies based on 

 monthly and annual means, and those based on daily weather maps. 

 In studying the statistical distribution of minima, he constructs a map, 

 showing the average number of minima passing through each square of 



