17 



ber, the interval being eight months ; at Catherinbourg (56° 

 49^ N., 60° 35^ K.) the first maximum occurs in the second 

 week of March and the second about the second week of 

 December, the interval being nine months ; at Tiflis (40° 42' N., 

 44° 50' E.) and at Lougan (48° 35' N., 39° 20^ E.) the inter- 

 val is also about nine months; at Stockholm, and also at 

 Milan, the first maximum occurs in the middle of February 

 and the second in the middle of December, the interval being 

 ten months; but in the British Islands there is only one 

 principal maximum, which occurs about the second week of 

 January and which appears to be formed by the union of the 

 first maximum of one year with the second maximum of the 

 year preceding, the interval between the two maxima being 

 twelve months. Jt is evident, therefore, that these maxima 

 move across the two continents in opposite directions, the 

 course of the first being from West to East and that of the 

 second from East to West. 



As the apparently compound maximum of January is not 

 greater than either of the separate maxima, the Author con- 

 siders it very probable that both maxima are produced by the 

 same disturbing cause, such disturbing cause taking its rise 

 in Eastern Asia in the month of November, and gradually 

 moving westward until it arrives in the British Islands in 

 January ; then reversing its course, it returns with a diminished 

 velocity to the region of its origin, where it arrives in the 

 month of April, and afterwards rapidly disappears under the 

 influence of an increasing temperature, to re-appear later in 

 the year on the return of a low temperature. 



As the times of first appearance and of final disappearance 

 of the disturbing cause in Eastern and Central Asia, corres- 

 pond very nearly with the times of the breaking up of the 

 monsoons in the China Sea and Indian Ocean, it is considered 

 very probable that the two systems of phenomena are directly 

 connected with and dependent upon each other. 



Attention is drawn to a very decided convexity of nearly 



