IN THE MEAN EFFECTS OF THE LARGER MAGNETIC DISTURBANCES. 121 
yet so obscure, should not be altogether overlooked. As the sun must be recognised 
as at least the primary source of all magnetic variations which conform to a law of 
local hours, it seems not unreasonable that in the case of other variations also, whether 
of irregular occurrence or of longer period, we should look in the first instance to any 
periodical variation by which we may learn that the sun is affected, to see whetlier 
any coincidence of period or epoch is traceable. Now the facts of the solar spots, as 
they have been recently made known to us by the assiduous and systematic labours 
of ScHWABE, present us with phenomena which appear to indicate the existence of 
some periodical affection of an outer envelope, (the photosphere,) of the sun ; and it is 
certainly a most striking coincidence, that the period, and the epochs of minima and 
maxima, which M. Schwabe has assigned to the variation of the solar spots, are abso- 
lutely identical with those which have been here assigtied to the magnetic variations. 
In the third volume of Kosmos, page 402 (English translation, vol. iii. pp. 291 and 
292), Baron von Humboldt has published a tabular abstract supplied by M. Schwabe, 
of the results of that gentleman’s observations of the solar spots from 1826 to 1850; 
from which M. Schwabe has derived the conclusion, that “ the numbers in the Table 
leave no room to doubt that, at least from the years 1826 to 1850, the solar spots have 
shown a period of about ten years, with maxima in 1828, 1837 and 1848, and minima 
in 1833 and 1843.” “ In almost all the years except those of the minima,” M. Schwabe 
says, ‘‘ I have observed large spots visible to the naked eye, — I mean spots whose 
diameters are above 50":” and 1847 and 1848 are enumerated amongst the years in 
which the largest spots appeared. M. Schwabe’s Table is as follows : — 
Table XXII. 
Years. 
Groups of spots. 
Days free from 
spots. 
No. of days of 
observation. 
1826 
118 
22 
277 
1827 
161 
2 
273 
1828 
225 
0 
282 
1829 
199 
0 
244 
1830 
190 
1 
217 
1831 
149 
3 
239 
1832 
84 
49 
270 
1833 
33 
139 
267 
1834 
51 
120 
273 
1835 
173 
18 
244 
1836 
272 
0 
200 
1837 
333 
0 
168 
1838 
282 
0 
202 
1839 
162 
0 
205 
1840 
152 
3 
263 
1841 
102 
15 
283 
1842 
68 
64 
307 
1843 
34 
149 
312 
1844 
52 
111 
321 
1845 
114 
29 
332 
1846 
157 
1 
314 
1847 
257 
0 
276 
1848 
330 
0 
278 
1849 
238 
0 
285 
1850 
186 
2 
308 
MDCCCUI, 
R 
