( 301 ) 



aii<l roii'iilnr sImIc of lii<' wcmIIkt. \nr\ iiiLi' (trcoiirsc \\ illi its u'eon'i-npli- 

 ical posilinii aii<l llic aclnal seasons, Iml dllicrw i^c rcciin-iiiu' IVoiii 

 vcar t(» vcar willi oiilv small accidciiial xarialioiis. 



As Ihiiius ar<', iiicicorolouical coiulitioiis are llic i'cNcrsc ('roiii r('lial)le. 

 Wc alti-ihiitc llicir \arial)ililv lo llic in-ctiiilaril v of llic radialioii lieUl. 



Tlic |)tM•lllia^•iti(^s of llic siirlaccs ol' (liscoiiliimit v add llioir (|iif)hi 

 ill dctci'Miiniiiii llic localilics, where iiiiiiinia of almosplicric |>ressiii'e 

 will occur; llicv iiilliiciicc llic dcplli and iiiox'ciiiciit ot' llie dc|»rossi(ms, 

 tlic course oC tlic cvcloiics. llic dii'cclioii ot' llic wind. llic lornialioii 

 ol' clouds and dic rainfall. 



Mkldkim found that between Ihe e(|nal(H' and 'io' soudieni lalitude, 

 cvcloues are more xiolenl and moi'e f're(|neiil a( spo! iiiaxima than 

 at niiiiima. Poky estahlished the same fact for the cyclones in the 

 Antilles; and to this a^üaiji it is attributed that in years of spctt maxima 

 dnrin<2,' the sprin;Li', sontii winds are i)redominant in Western Knrope ; 

 that less frosty days occur at that .sea.son, the ice melts at an earlier 

 date than usual, the \valei'-mark stands higher for flie great rivers, 

 plants are more forward, etc. (x\RHnKMrs Lehrbuch d. kosm. Phys. 

 p. 141—146). 



Neither does it seem out of place to attribute the jieriodical alter- 

 nations of years w ith much rain and years of drought in l>ritisli 

 India ^), which react in so conspicuous a manner on the economical 

 condition of that country, to the periodicity in the varying position 

 of the Earth with respect to the surfaces of discontinuity. An excess 

 of rainfall seems there a regular occurrence \\ithin a three year 

 period around the maximum and a three year period around the 

 minimum of sun-sj)Ots. The intervening years are marked by drought, 

 the cause of famine. The regular course of these meteorological 

 phenomena was interi'u[)ted in 1899, w hen great drought aiul excessive 

 famine coincided w ith a spot minimum ; but at the same time the 

 widened lines of the spot s[)ectrum jiresented an abnormal appeai'ance. 

 Here again \ve lind a ciirumstance iji su|)|)oi't of oin- assumption, 

 that the irregularities of the meaji atmospheric circidation are caused 

 by the surfaces of discontinuity . How (wer, similar local meteorological 

 phenomejia depend on so many conditiojis, that we dare not look 

 forward to a speedy solution of the j)roblems they present. 



Summary of results. 

 Overlooking the results of this investigation we see that the prin- 



1; Sir N. LocK.ER and \V. J. S. Lock^er, "On Solar Ciianges of Temperature 

 and Variations in liainfall in the Region surrounding the Indian Ocean". Proc. 

 Roy. Soc. London 07, p. 409—431 (lliUl). 



