1880.] 



in Itf'hition io tlie i^iin-spot Cycle. 



71 



from eleven, and, in that of Nancowry, from six years' registers. On the 

 mean of the whole period and of the two stations, the excess amounted 

 to ■0327". 



The single exceptional station, which shews a greater average excess 

 than the Bay islands, is the hill station of Darjiling iu the Sikkim Hima- 

 laya, at an elevation of nearly 7000 feet above the sea. At this station, 

 ■where the barometer has been registered steadily for upwards of 12 years, 

 the mean excess of the same period of 28 months was not less than -0332" ; 

 or, since the first rise took place in August 1876, the mean of the whole 

 unbroken period of 25 months' excess was •0379". On the plains of Bengal, 

 the mean excess (average of six stations) was only -0298 on the 28 months 

 and •0351i on the 25 months, a reduction, as compared with Darjiling, which 

 is probably explained by the fact that, in Bengal, as indeed generally in 

 India, the mean temperature of the air was also on the whole considerably 

 in excess of tlie average ; so that the stratum of air resting on the plains 

 had less tlian the average density. This fact is of pregnant importance ; 

 for it shews that the excessive pressure in question was due to the condition 

 of the higher atmosphere ; of those strata, at all events, that lay above the 

 elevation of 7000 feet ; and that, in fact, the prevailing excess, instead of 

 being caused by the conditions recorded at observatories on the plains, was 

 to some extent counteracted by a deficiency in the mass and static pressure 

 of the lower strata. 



In his report on the Meteorology of India in 1877, Mr. Eliot drew 

 attention to the persistently high barometric pressure of that year, and 

 pointed out that the barometric registers of Sydney and Melbourne in 

 Australia also " indicated, on the whole, a marked tendency to excessive 

 pressure ; and that, therefore, there is a slight probability that this is a 

 feature of the whole area, from India southwards to Australia, including 

 the sea area of the Indian Ocean." Furthermore, that it appeared, from 

 the register of Hongkong, " that the pressure in that part of China was as 

 markedly and persistently in defect as it was in excess in India." 



A re-examination of the data shews, however, that this latter conclu- 

 sion is extremely doubtful, and indeed probably mistaken. I find that the 

 Hongkong barometric registers of past years have been so variously treat- 

 ed that no trustworthy comparison can be instituted on them ; and, on the 

 other hand, I find that the excellent registers of Zi-ka-wei near Shanghai 

 point to an opposite conclusion, and shew that here also, on the east coast 

 of China, the pressure was excessive during the greater part of the period 

 in question, though to a much less degree than in the Indian region. 



In the case of Australia, Mr. Eliot com^^ared the registers of Sydney 

 and Melbourne only. I have examined that of Adelaide in addition, and 

 find that not only does it confirm the general conclusion drawn from the 

 two former registers, but, further, shews that in South Australia the excess 



