462 



BEronT — 1884. 



such a decided sunspot period, both in the quality and in the quantity fif 

 its produce. 



Dr. Hunter has endeavoured to connect together the years of famine in 

 Southern India with the sunspot minima. The question of famines in, of 

 course, intimately connected with that of rainfall, which latter, as T have 

 pointed out, has not hitherto yielded any very decided results. T'.ie diffi- 

 culty consists in the local circumstances which at different plfices com- 

 plicate the result very much ; and while it is therefore imposfiible to deny 

 a certain value to Dr. Hunter's conclusions, we shall do wnl to suspend 

 our judgment until another sunspot cycle will have given us more ample 

 material. 



Stanley Jevons ' has pointed out a periodicity in commercial crises, 

 «,nd has endeavoured to connect it with the sunspot period. 



The regular i-ecurrence of crises at an interval of a little over ten years is 

 very striking, but the disagreement of i!ie period itself with that of the sun- 

 spots is fatal to the hypothesis of any true connection. Jevons was misled, 

 by a paper of Allan Broun, to adopt a wrong average period for the sunspot 

 activity. Sunspots were vei-y irregular at the end of last century, and there 

 seemed at one time a doubt whether we ought to count two long or three 

 short periods between the years I880 and 1804. Wolf adopted the former, 

 and Allan Broun the latter view. Accordingly they obtained different 

 values for the average sunspot period. 'J^hfi-e seems at present to be no 

 doubt that 11"1 years is the true average period, as this is the length wo 

 obtain by leaving out of account altogtsther the period of irregularity. 

 The very regularity indeed of the series of commercial crises is an argu- 

 ment against its connection with the sunspot period, which itself is rather 

 irregular in length. Wo find, indeed, that those teri-estrial phenomena, 

 which are proved to depend on the presence or absence of sunspots, imi- 

 take of the same irregularities which are shown by the sunspot curves. 



An important contribution to the discussion of the general question wiis 

 made by Professor J. H. Poynting.* His primary object was to determine 

 whether there was a general meteorological cause operating, which, during 

 certain years, influenced the yield of certain crops in the same way all over 

 the world. If this is so, the curves representing these yields ought to 

 Lave approximately the same shape in every country. We need not lierc 

 enter into the method which Professor Poynting has used to smooth down 

 his curves. The result of his investigation seems to show that the price 

 of wheat has varied approximately ra the same manner in England and in 

 Delhi. The curves representing the cotton crops in different countries 

 show a still more striking resemblance to each other, and the yielil of 

 cotton seems to vary inversely as that of the wheat crop. All tliis is (h's- 

 tinctly in favour of a common meteorological cause affecting widely 

 different parts of the earth in the same way. There seems, however, w 

 striking similarity between the crops and the variation of sunspots, except 

 in the case of the silk crop in China, as shown by the curve of imports 

 from that place. 



Cosniical Phenomena. 



Although wo are here directly only concerned with terrestrial matter.^ 

 it seems yet of importance to point out that the causes which are operat- 

 ing will very likely be found to operate all through the solar system. The 



• Nature^ xi.x. p. 588 (1879). 



Froo. Stat. Soc. vol. xlvii. p. 2\Q. 



