66 REPORT—1885. 
The Committee are of opinion that these are steps which might at 
once be taken, so as to push on this part of the subject. 
The Committee would call attention to the completeness of the mag- 
netical information which is given by the present method of publication 
adopted by the Astronomer Royal. He now gives, in addition to the 
mean values of the magnetic elements for each day and the mean diurnal 
curves for each month, the amplitude of the diurnal curve for each day, 
and particulars of all disturbances, small as well as large. (See Appendix, 
No. IX.) 
Until a method is generally accepted for determining the normal solar- 
diurnal variation, it seems premature to raise any discussion on the best 
way of estimating disturbances, since these cannot well be measured 
except from the basis of such a normal. 
The Committee would, however, allude to various investigations, 
chiefly connected with disturbance, which are being undertaken by some 
of its members. The thought seems generally to have occurred that dis- 
turbances may denote the method by which the earth rights itself with 
respect to the magnetic forces acting upon it (see Appendix, No. II., para- 
graphs 11 and 12), and this idea underlies the various researches about 
to be named.! 
The first of these is that already mentioned as having been taken up by 
Sir J. H. Lefroy, with the concurrence of the Astronomer Royal—namely, 
a comparison of magnetic movements photographically recorded at 
Toronto and Greenwich in the years 1849-53. Stations so far asunder 
(3,100 miles), and on different continents, appear calculated to throw 
light on many questions which are not much advanced by comparison of 
stations in geographical proximity. 
The following are primd facie conclusions which may require modifica- 
tion when the work has been gone through, but which already seem to 
have a bearing on the physical explanation of the phenomena :— 
a. A similar state of magnetic weather, so to speak, prevails generally 
at both stations, so that where numerous or extensive deviations from 
normal regularity occur at the one, there is generally something corre- 
sponding at the other. 
b. The correspondence very seldom amounts to similarity of movement 
or identity of time. 
c. The changes of declination at Toronto are more rapid than at 
Greenwich. This is especially observable about the time of the morning 
easterly extreme. Bold sweeping curves with a long time measure are 
much less common at Toronto than at Greenwich, and can seldom be 
identified. 
d. On the other hand, shocks of small angular amount breaking a 
uniform line are often capable of identification, and are simultaneous, 
or nearly so, at both stations. 
e. Although the declination was westerly at both stations, the move- 
ments of disturbance are very frequently, probably usually, in opposite 
directions at any given time—easterly at Greenwich, or decreasing the 
absolute declination, when they are westerly, or increasing it, at Toronto. 
f. The same days would generally be selected to form normal curves 
at both stations. 
1 A similar idea seems to have occurred to Dr. Wild (see foot-note to his communi- 
cation, Appendix, No. VII.). 
