REPORT—1854. 
364 
the atmosphere or of the earth. Until this connexion was observed, do 
correspondence whatsoever, though carefully sought, had been found between 
any other known phenomena, either cosmical or terrestrial, and the affections 
which we perceive to take place with so much regularity and to so great an 
extent in the solar disc. On this subject, therefore, 1 am now especially 
desirous to put before you the precise amount of the correspondence»iih 
the magnetic variations which has been discovered; since, if it should be 
continued by farther experience, it may not unreasonably be expected to 
throw an important light on many matters of high scientific imporlance,- 
such as the nature of the solar spots themselves, the mode of action by 
which magnetic effects are produced by the sun upon the earth, and possibly 
even upon the nature of magnetism itself. 
The observations employed in the investigation were the hourly observa¬ 
tions made at two observatories, Toronto and Hobarton, the stationsbeiiij 
in opposite hemispheres and nearly in opposite points of the globe. Tie 
observations commenced in the latter part of 1842, and were maintained for 
five years, terminating consequently in the latter part of 1848. Every ob¬ 
servation occurring in these five years which exceeded a certain amount o' 
difference from the mean value in the same month and at the same hour, was 
considered a disturbed observation, and being separated from the rest, these 
constituted the body of disturbed observations, which were made the subject 
of examination at each station. By assuming an arbitrary and somewhat 
large magnitude as the standard of disturbance, the observations separated 
wiiro doubtless less in number than would have been the case had it been 
possible to have adopted an absolute criterion; but one and the same mas* 
nitude having been preserved as the standard in each of the years, the re/a- 
tur frequency and relative aggregate values in the different, years were 
obtained, very approximative))* at least, in their just proportions. At esc 
station the disturbances were found to increase, both in frequency and in 
aggregate values, progressively from 1843 to 1848; the aggregate value o 
the disturbances in 1848 being, both at Toronto and Hobarton, about tine 
tunes greater than in 1843.' It happened that at the very time WPM* 
somewhat laborious investigation had conducted me to this result, I had 
^ejne, in the third volume of M. de Humboldt’s ‘ Kosmos/ the results o' 
.1. Schwa be s observations of the solar spots from the year 1826 to b- 1 
then first made public: for the portion subsequent to 1844, and I wasimmi- 
tl lately and most forcibly struck by the coincidence both in period and fp 
w-ith the variation announced by him in the frequency and amount of w 
spots of which a minimum was also in 1843 and a maximum in 1846. o 
hourly series of observations at Toronto having been preceded by a ^ 
houriy senes in 1841 and 1842, a similar examination was made of tin* 
years when it was found that the magnetic disturbances as well as the ^ 
? 13 j lltreased 1 ,n , S 0,n g backwards from 1843. A similar examination^ 
wTch aTl\ '"i, *7 Caj,tain Younghusband, recently my assistant at V^ 
the ; s ° b i e at St* Helena and at the t&pe of Good Hope, a 
he series 0 f Z?** . COm " lunicat * d by bin, to the lloVal Society. Tk- 
s vc tlmn It T ? ,,0n8 , from which "suits are derived was less «*■ 
X H ° baPtto » ceasing at the Capem«f " 
stations is 1813 ^nn I . f , hc J C£tr of minimum disturbance at both the la! ■ 
Having thiish?ki. le - ,n r rea - e * P r °g re « s ' v e to the close of the sera* 
magnetic variation® '5 , ,ndrc 5* lon a connexion between certain of 
by the termination a !! d ^ l e solar spots, limited unfortunately in respect 
nmrkably'accordant 0 * **u* e ° u bser ^ ti P"« at the Colonial Observatories burn; 
w ithm those limits, it was natural to examine whether . 
