1880.] 



in lielation to tlw Sim-sjwt Cycle 



81 



(perhaps including China) having a period which coincides with that of 

 sun-spot variation ; and that Tiflis on the one hand and Nertschinsk on the 

 other lie beyond the limits of its influence. 



Now, seeing that the Indo-Malayan barometric maximiim of 1876-78 

 coincided with a portion of the prolonged sun-spot minimum of 1876-79, 

 the facts detailed above would lead us to expect a corresponding deficiency 

 of pressure in Western Siberia. Strange to say, however, this was not the 

 case. The registers of Bogolowsk, Ekaterinenburg, Slatoust, and Barnovil 

 agree in showing a great excess of pressure in 1877, which in the 

 case of Ekaterinenburg was greater than that of any Indian stations, 

 and nearly as great as that of Adelaide. I have not yet received 

 the volume of the ' Annales' for the year 1878 ; but, on the average of the 

 20 months from May 1876 to December 1877, it amounted to -0611." The 

 great excess appears to have been restricted to the stations in Western 

 Siberia. At St. Petersburg, although the pressure was above the average 

 in 1876 and 1877, the excess was far less striking ; and that of 1877 was 

 less than that of 1876. At Tiflis, the pressure of the two years was either 

 about the average or below it ; and, at Pekin and Nertschinsk, it was 

 not greater than at Shanghai [Zi-ka-wei]. 



Hence, there prevailed in Asia generally, in 1877, an anomalous {i. e., 

 apparently non-periodic) accumulation of atmospheric pressure, culminat- 

 ing in Western Siberia, and diminishing both to East and West, and also to 

 South. And this seat of maximum lies on the prolongation to the North- 

 west of the Indo-Malayan axis of excessive pressure noticed in the earlier 

 part of this paper. It is at least probable that this anomalous accumula- 

 tion of pressure extended in a much diminished degree to the Indo-Malayan 

 region, where it was superimposed on the normal periodic excess of that 

 region, and produced a maximum which was more intense than any pre- 

 viously recorded. Also that the excessive pressure of Australia was a 

 phenomenon of the same order as that of Siberia ; indeed its southern 

 counterpart. It is at least certain that they exhibit a resemblance in 

 certain not unimportant features to which I shall draw attention in a sub- 

 sequent paper; merely remarking that, in both cases, these great oscillations 

 of pressure, both periodic and non-periodic, appear to depend mainly, perhaps, 

 indeed, entirely, on the variations of the winter season. Of this, in the case 

 of Ekaterinenburg more esj^ecially, the evidence is most striliing and con- 

 vincing, and, as far as I have yet examined the Australian registers, it 

 appears to hold good in their case also. 



11 



