SUN-SPOTS AND FAMINES. 



133 



am'med the temperature-observations recorded 

 during thirty years at the Cape under his prede- 

 cessor, Sir T. Maclear. He stated that the tem- 

 perature and sun-spot curves presented an agree- 

 ment so close as to compel him to believe that 

 tire same cause which leads to an access of mean 

 annual temperature leads equally to a dissipation 

 of solar spots. Here, also, we find the maximum 

 heat slightly lagging behind the minimum spots. 

 In 1S73 Signor Celoria, from a comparison of the 

 sun-spot periods with the rainfall at Milan from 

 1763 to 1S72, came to the result that the coinci- 

 dence was marked, but not very decidedly. Dr. 

 W. Koppen's papers in the Ztitschrift dcr oster- 

 reichischen Gesellschaft fur Meteorohgie for Au- 

 gust and September, 1873, form the most im- 

 portant contribution upon the question. He en- 

 deavored, with an elaboration and completeness 

 not previously attempted, to present the earth's 

 temperature in connection with sun-spots for the 

 hundred years preceding 1S70. He divided the 

 thermometric returns into two great classes — 

 those taken within the tropics, and those be- 

 longing to the extra-tropical zones. The barest 

 summary of his researches would occupy several 

 pages. In a carefully-prepared chart he exhibited 

 the rainfall and sun-spot curves from 1768. Dur- 

 ing the earlier part of this period he had thermo- 

 metric returns only from the northern temperate 

 zone. The curves do not show a coincidence ; 

 whether from the local character of the tempera- 

 ture returns, or from the uncertain value of the 

 sun-spot curve, we need not here inquire. After 

 the year 1826, when the sun-spot data become more 

 trustworthy, the case is entirely different. The 

 curves follow each other in a most striking man- 

 ner; and, indeed, he states that, from 1816 to 1S54, 

 the coincidence of temperature-changes with the 

 sun-spots does not merely extend over the aver- 

 age length of the cycles, but reflects all the lead- 

 ing disturbances and peculiarities of the sun-spot 

 periods. Dr. Koppen further points out that, as 

 the period of increase from the minimum to the 

 maximum year in ihe sun-spot cycle is almost al- 

 ways shorter than the period of decrease from 

 the maximum to the minimum, so, on the whole, 

 is that feature reflected in the temperature- 

 changes. The parallelism in this series of re- 

 turns, he says, with reference to his table dealing 

 with the period from 1820 to 1854, is so great, 

 that there can be no question of accidental coin- 

 cidence of variations independent of each other. 

 On the other hand, his figures disclose many 

 anomalies. Thus, in the tropics, the maximum 

 of warmth occurs a full year before the year of 



minimum sun-spots ; while in the zones beyond 

 the tropics it falls two years after the minimum. 

 The regularity and magnitude of the undulation 

 of the temperature-curve are most strongly marked 

 in the tropics, and decrease toward the poles. 



With regard to the third class of phenomena, 

 wind-disturbances, the evidence, although less 

 abundant, is more uniform. The frequency of 

 such disturbances at times of maxima sun-spots 

 has been observed independently by two me- 

 teorologists on the opposite sides of the globe. 

 In both cases their observations were made in 

 the tropics, where wind-disturbances have so vio- 

 lent and so well-marked a character as to admit 

 of more easy enumeration than in the extra-trop- 

 ical zones. To our countryman Dr. Meldrum, 

 government-astronomer at Mauritius, belongs the 

 honor of originating, with the chief credit of 

 prosecuting, this research. By a series of care- 

 ful observations he had, more than five years ago, 

 established the existence of a coincidence be- 

 tween the frequency of cyclones and sun-spots. 

 In 1872 one of the writers of this article thus 

 summarized the results : " Mr. Meldrum teHs us 

 that the whole question of cyclones is a question 

 of solar activity, and that, if we write down in 

 one column the number of cyclones in any given 

 year, there will be a strict relation between them 

 — many sun-spots, many hurricanes ; few sun- 

 spots, few hurricanes. Mr. Meldrum points out 

 that, in those years in which we have been quietly 

 mapping out the sun-spot maxima, the harbors 

 were filled with wrecks and vessels coming in 

 disabled from tvery part of the great Indian 

 Ocean." Next year, 1873, M. Poey, who had 

 conducted a similar research into the hurricanes 

 of the West Indies, communicated his results to 

 the Aeademie des Sciences at Paris. He enu- 

 merated 357 hurricanes between 1750 and 1873, 

 and stated that, out of twelve maxima, ten agreed. 

 A careful reexamination of his materials discloses 

 striking coincidences, but at the same time, we 

 ought to add, very serious discrepancies. The 

 discrepancies, however, chiefly belong to the last 

 century and the earlier part of the present one. 

 Since the commencement of Schwabe's continu- 

 ous sun-spot observations in 1826, the common 

 periodicity is more strongly marked, as Table 

 III., on page 139, will show. 



During the present summer, 1877, an effort 

 has been made to ascertain whether the periodici- 

 ty thus observed in the wind-disturbances of the 

 tropics produces any well-marked results upon 

 the shipping of the world. Mr. Henry Jeula, 



