502 



MR BALFOUR STEWART ON SUN-SPOTS AND THEIR 



With respect to Jupiter, these records do not enable us to come to any con- 

 clusion ; perhaps the reason of this may be, that the diameter of the sun is very 

 insignificant compared with the great distance of this planet, and that we ought 

 rather to look for its influence in some change produced on the sun's surface, as 

 it passes from perihelion to aphelion. In the interesting volume on Sun-Spots, 

 recently published by Mr Carrington, we have a comparison of this nature, the 

 results of which are embraced in the following table : — 



Comparison of the dates of greatest and least Sun-spots, with those of the 



GREATEST AND LEAST RADIUS VECTOR OF JUPITER. (FrOM Mr CaRRINGTON's CuRVES.) 



Difference. 



Greatest 



Maximum 



Slongation. 



of Spots. 



1863-0 - 



1860-7 



1851-1 - 



1848-9 



1839-2 - 



1837-4 



1827-4 - 



1829-7 



1815-4 - 



1816-8 



1791-9 - 



1788-6 



1780-0 - 



1779-5 



1767-9 - 



1770-5 



1756-2 - 



1761-6 



1856-8 - 



1855-9 



+ 



2-3 

 2-2 

 1-8 

 2-3 

 1-4 

 3-3 

 0-5 

 2-6 

 5-4 

 0-9 



Least 



Minimum 





T\H 





nongation 



of Spots. 





Dl 



leren 



1845-1 



- 1843-2 



= 



-f 



1-9 



1833-2 



- 1833-5 



= 







0-3 



1821-4 



- 1823-0 



= 



— 



1-6 



1809-4 



- 1810-0 



= 







06 



1797-7 



- 17980 



= 



— 



0-3 



1785-9 



- 1784-4 



= 



+ 



1-5 



1773-9 



- 1775-2 



Z3 



— 



1-3 



17620 



- 1766-2 



z= 



— 



4-2 



1750-1 



- 1758-5 



zrz 



_ 



5-4 



On this subject, also, Mr Carrington makes the following remark. " It will 

 be seen that from the year 1770 there is a very fair general agreement between 

 maxima of frequency and maxima of Jupiter's Radius Vector, and between 

 minima and minima, with such an amount of loose discrepancy, as to throw 

 grave doubt on any hasty conclusion of physical connection. In the two periods 

 which precede that date, there appears to be a total disagreement ; and although 

 the data for frequency are less certain for those years, yet the general form of 

 the curve of Professor Wolf, is probably too well established to admit of any- 

 thing like reversion, by the addition of other observations which have not yet 

 come to hand." Now, every one must agree, that caution is very requisite in a 

 generalization of this nature. On the other hand, I am tempted to think that the 

 behaviour of sun-spots, to which allusion has been made in this paper, is very 

 conclusive as to the fact of planetary action, and if this be allowed, it must also 

 be admitted, that Mr Carrington' s results, on the whole, lead us to believe, that 

 the recession of Jupiter from the sun is favourable to the breaking out of spots, 

 and his approach unfavourable to their production. Coupling this with what I 

 have already endeavoured by a different process to make out regarding the action 

 of Venus, we may perhaps conclude it probable, that the approach of a planet to 

 any portion of the sun's surface, or that of the sun's surface to a planet, is un- 

 tavourable to spot production, while the recession from the sun of a heavenly 

 body is favourable to the same. 



Let us now see what support this conclusion derives from the phenomena of 



