EDITOR'S TABLE. 



3 6 5 



THE SUN-SPOTS AND THEIR EFFECTS. 



The phenomena of sun-spots are 

 now familiar : multitudes of people 

 have seen them, and everybody has 

 read about them. It is well known 

 that the surface of the sun is not that 

 uniform disk of light that it was for- 

 merly supposed to be, but abounds in 

 gulfs, dark chasms, up-rushing streams 

 of flaming gases, and lurid promi- 

 nences, sometimes 100,000 miles high. 

 But these striking effects are not uni- 

 form : the sea of solar fire, like our 

 own oceans, is sometimes violently agi- 

 tated and sometimes quiet. The spots 

 are variable, being now many and enor- 

 mous in size, and again few and small. 

 This periodicity, moreover, is proved 

 to be regular. Prof. Schwabe, of Des- 

 sau, discovered that, instead of being 

 uniform in number and intensity from 

 year to year, spots increase and decline 

 at definite rates for a term of years. 

 As a result of 9,000 observations, dur- 

 ing which he discovered 4,700 groups, 

 he traced three complete oscillations 

 from maximum to minimum, which he 

 estimated to take place in about ten 

 years. Prof. Wolf, of Zurich, went 

 into an exhaustive history of the sub- 

 ject, and, by collating a vast number of 

 observations and records from 1750 to 

 1860, he verified Schwabe's general re- 

 sults, but showed that the period of 

 oscillation is about eleven years. His 

 data, scattered through a course of 140 

 years, comprehended observations in 

 the seventeeth century made on 2,113 

 days ; in the eighteenth century, on 

 5,490 days; and in the nineteenth cen- 

 tury, on 14,860 days, or a total of 22,463 

 days. On this broad basis of observa- 

 tion, made with no reference to any 

 hypothesis of variation, it is established 

 that the solar energy changes in inten- 

 sity by a regular law of rise and fall 

 from a maximum to a minimum of ef- 

 fect; and that the maximum, or great- 

 est activity, coincides with the period 

 of violent perturbation when there is 



the greatest number of eruptions of 

 heated matter from below, and the 

 most conspicuous display of sun-spots 

 and prominences; while at the mini- 

 mum periods these manifestations are 

 greatly reduced, or almost entirely 



wanting. 



It is now an admitted fact of sci- 

 ence that the earth is dependent upon 

 the sun for the chief portion of the en- 

 ergy by which terrestrial effects are pro- 

 duced. With the exception of the ebb 

 and flow of the tides, all the forms 

 of earthly power are recognized as hav- 

 ing, directly or indirectly, a solar ori- 

 gin. "Wind-power, water-power, steam- 

 power, the activities of organic growth, 

 all animal energy, and the great phe- 

 nomena of changes in the crust of the 

 globe, due to the circulation of waters 

 through atmospheric agency, are caused 

 by the forces of solar radiation. But 

 if the solar energy is variable, the ques- 

 tion naturally arises, "Is that variation 

 manifested in terrestrial effects, and, if 

 so, in what manner, and to what ex- 

 tent? " The subject is vast and new, but 

 the indomitable energy of modern sci- 

 entific inquiry has rapidly accumulated 

 evidence which answers the first ques- 

 tion in the affirmative, and gives in- 

 structive replies to the others. The 

 sun-spots, for thousands of years un- 

 known, and for centuries after they 

 were known regarded as mere mat- 

 ters of curious and idle speculation, are 

 now linked indissolubly to the whole 

 scheme of activity which we observe 

 upon earth, and of which we are our- 

 selves a part. Even the famines by 

 which nations are periodically deso- 

 lated seem to be connected with this 

 intermittence of solar energy. The 

 evidence upon the subject has been 

 summed up in an able and impressive 

 paper contributed by Messrs. Lockyer 

 and Hunter to The Nineteenth Cen- 

 tury, and which will be found in full 

 in No. VIII. of The Populak Science 

 Supplement. We can here do little 

 more than indicate the remarkable con- 



