68 COSMOS. 



rounded by sJiallows or penumbrse, where the action is more 

 tumultuous." 



The black spots, which are seldom round, almost always 

 angularly broken, and characterized by entering angles, are 

 frequently surrounded by halos or penumbra, which exhibit 

 the same figure on a larger scale. There is no appearance 

 of a transition of the color of the spot into the penumbra, or 

 of the latter, which is sometimes filamentous, into that of the 

 photosphere. Capocci and Pastorff (of Buchholz, in Bran- 

 denburg) most diligent observers have both given very 

 accurate representations of the angular form of the nuclei. 

 (Schum., Astr. Nadir., No. 115, p. 316 ; No. 133, p. 291 ; 

 No. 144, p. 471.) William Herschel and Schwabe saw the 

 nucleoid spots divided by bright veins or luminous bridges 

 phenomena of a cloud-like nature generated within the second 

 stratum where the penumbrse originate. These singular con- 

 figurations, which probably owe their origin to ascending cur- 

 rents, the tumultuous formation of spots, solar faculse, furrows, 

 and projecting stripes (crests of luminous waves), indicate, 

 according to Sir William Herschel, an intense evolution of 

 light ; while, on the other hand, according to the same great 

 authority, " the absence of solar spots and their concomitant 

 phenomena seems to indicate a low degree of combustion, and, 

 consequently, a less beneficial action on the temperature of 

 our planet, and the development of vegetation." These con- 

 jectures led Sir William Herschel to institute a series of com- 

 parisons between the prices of corn and the complaints of poor 

 crops, * and the absence of solar spots, between the years 1676 

 and 1684 (according to Flamstead), from 1686 to^!688 (ac- 

 cording to Dominique Cassini), from 1695 to 1700, and from 

 1795 to 1800. Unfortunately, however, we can never attain 

 a knowledge of the numerical elements on which to found 

 even a conjectural solution of such a problem ; not only, as 

 this circumspect astronomer has himself observed, because the 

 price of corn in one part of Europe can not be taken as a cri- 

 terion of the state of vegetation over the whole Continent, but 

 more especially because a diminution of the mean annual 

 temperature, even if it affected the whole of Europe, would 

 afford no evidence that the Earth had derived a smaller 

 quantity of solar heat throughout that year. It appears from 

 Dove's investigations of the irregular variations of tempera- 

 ture, that extremes of meteorological conditions always lie 



* William Herschel, in the Philosophical Transactions of the Royal 

 Society for 1801, part ii., p. 310-316. 



