358 TRANSACTIONS OF THE CANADIAN INSTITUTE. [VoL. VI. 
Ptolemaic system, when, in Milton’s phrase, the heavens were “with 
cycles and epicycles plastered o’er.” Yet, to one who traces them 
time and again, there comes a conviction that there is some rhythm 
underlying the seeming confusion. As the movements of the heavenly 
bodies were seen to be subject to simple laws so soon as they were helio- 
centrically regarded and the mathematical astronomer learned to look 
out upon the cosmos from its local ruliag body, so a beginning having 
been made to refer magnetic motions to the pivot of the needle instead 
of merely noting those of its extremities, we may hope that their com- 
plexity will vanish. When such motions are expressed in measurements 
of angles, and a mean adopted like the thermometrical zero, simplicity 
may replace apparent confusion. Diurnal movements may perhaps be 
eliminated, as being the effect of heat or solar distance, neutralising each 
other as the earth rotates. Seasonal changes may in like manner bal-_ 
ance each other, hemisphere against hemisphere, and be removable too. 
Abstracting these and local elements, should we not be left with a curve 
depending upon solar activity alone? Then we should have, by means 
of wireless telegraphy between Sun and Earth, the exact measure and 
period of solar excitation, which, as now measured by sun-spot area and 
position is uncertain and irregular, for these are not an accurate index 
to the violence of sun-spot phenomena. Then, although we may not, in 
Mr. Preece’s language, hear on this earth the thunderstorms in the sun, 
solar weather will be found to be governed by the intensity of solar out- 
breaks, the maxima and minima of sun-spots will likely coincide with 
those of prominences, and regularity will resume its sway. Possibly 
we may then hope to derive practical human advantages from under- 
standing the connection between solar weather and our own.* 
*Since the date of this paper Prof. Kreutz, of Kiel, Germany, has been so obliging as to send me 
several ‘comet notes.”. Some are remarkable, but especially the following:—‘‘ Comet, 1888, I,, on the 20-21st 
May, suddenly changed its appearance.” On May 2oth the greatest magnetic storm of the half year occurred, 
the lowest dip being at 23 o'clock of the 2oth, There were many magnificent auroral displays on the earth, 
while the changes in the appearance of the comet were proceeding. Mr, A. Elvins has given me the date or 
changes in Swift’s comet, 1892, I., viz.:—April 6th and 7th, which were the dates of sharp vibrations of 
the magnetic needle. Herr Leo Brenner, of the Manola Observatory, Lussinpiccolo, Austria, only once 
observed a brilliant aureole round the dark side of Mercury; it was on May 18th, 1896, which was the 
crisis of a magnetic storm on earth, The aureolar phenomena of Venus are now under investigation, to 
ascertain if they are so co-incident with magnetic storms here as to prove a connection, —THE AUTHOR, 
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