296 : REPORT—1858, 
tories only, without taking into consideration those deducible from observa- 
tions made under foreign auspices; and they find that, at the cost of an 
expenditure which may be reckoned at about £400 per annum (exclusive 
of the cost of instruments, outfit, and publication), for each of the several 
observatories at St. Helena, Toronto, Hobarton, and the Cape of Good 
Hope during the respective continuance of each, the accumulated observa- 
tions, so far as they have yet been discussed, have produced the following 
results, which they consider as satisfactorily established by the discussion :— 
In the first place, the mean state of the several magnetic elements for each 
of the stations, as reduced to a fixed epoch, has been obtained with a pre- 
cision of which nothing previously done has afforded any example—emula- 
ting, in this respect, the exactness of astronomical determinations, and com- 
petent to serve as a fixed point of departure, to the latest ages ; and this for 
each of the elements in question—the dip, the declination, and the intensity 
of the magnetic force. 
Secondly, that at each station, the rate of regularly progressive secular 
change in all the three elements above-mentioned has been ascertained with 
a degree of precision which contrasts strongly with the loose and inaccurate 
determinations of former times. 
Thirdly, that the laws of the diurnal, annual, and other periodic fluctua- 
tions in the values of these elements, as exhibited at each station, have been 
established in a manner and with a decision to which nothing hitherto 
executed in any branch of science, astronomy excepted, is comparable; and 
that the results embodied in the examination of these laws have laid open a 
view of magnetic action so singular, and so utterly unexpected, as to amount 
to the creation of a new department of science, and the detection of a com- 
pletely novel system of physical relations: for that, in the first place, the 
systems of diurnal and annual magnetic changes have each been separated 
into two perfectly distinct and physically independent systems,—the one, at 
any particular station, holding its course according to laws depending solely 
on the sun’s hour-angle at the moment of observation, and his meridian 
altitude at different seasons; the other comprehending all those movements 
which, under the name of magnetic storms, or “irregular disturbances,” have 
hitherto presented the perplexing aspect of phenomena purely casual, 
capricious in amount and in the particular occasions of their occurrence 
when regarded singly, has been shown, by these discussions, to be subject 
in its totality to laws equally definite with the others, though more dependent 
for their application on peculiarities of local situation. As regards the first 
of these systems of fluctuation, they find it demonstrated :— 
That the sun’s regular action on the magnetism of the globe is deter- 
mined by a law of no small complexity and intricacy, but which, nevertheless, 
has been traced with precision and certainty, and shown to be referable, in 
the first place, and for one of its arbitrary coefficients, to the geographical 
situation of the place of observation with respect to a certain line or equator 
on the earth’s surface, which cannot yet be precisely traced for want of 
sufficiently numerous stations (but which seems to approach to the line of 
least intensity and is very far from coinciding with the geographical equator), 
—and in the next, and for its other influential cause, to the fact of the 
sun’s having north or south declination ; so that the whole diurnal change 
in any one of the elements, and at any station, is made up of two portions, 
one of which retains the same sign, and a constant coefficient all the year 
round ; the other changes sign, and varies in the value of its coefficient with 
the annual movement of the sun from one side of the equator to the other. 
That, consequently, for a station on the magnetic equator (so defined), 
