The Sun.
London, England, 1842-01-11 00:00:00

PRICE 5d

MAGNETIC DISTURBANCE.
(From the Literary Gazette.)
SI3IULTANEOUS OBSERVATIONS AT GREENWICH, AT
TORONTO IN CANADI, AT TREVANDRUM IN THE
EAST INDIES, AT ST. HELENA, AND AT THE CAPE OF
GOOD HOPE, DURING THE REMARKABLE MAGNETIC
DISTURBANC:;: ON THE 25TH AND 26TH OF SEPT. 1811
Military organisation and military habits made avail-
able by the British Association in scientific researche,
are beginning to develope their advantages ; an'l Ce
very recent and prompt publication by that body afford,
proof that the constitution of the association, and the
system of magnetic observatories proposed and being
carried out by them, are working well, Look at the
date of the " disturbance," and see how soon the account
of it is brought together from the four quarters of the
globe, and published ! It is satisfactory, also, to find
that the disturbance has not escaped the vigilance of
any one of the observatories from which accounts have
yet been received. With observers thus trained, and
a system thus organised, it would be difficult to predict
the results.
Colonel Sabine, in the introductory remarks, refers
to the interest which Mr. Airy's circular letter on the
subject of the magnetical disturbance observed at Green
wich on the 25th September last has excited ; to the
approval of the Master-General of the Ordnance for
the immediate publication of the observations con-
ducted by the officers of the Royal Artillery at the
magnetical observatories ; and to the employment, for
that purpose, by the Committee of the British Associ-
ation (of which the Gallant Colonel is a prominent and
eminent member) appointed to conduct the co-opera-
tion of that body in the system of simultaneous mag
netical and meteorological observations, of a portion 01
the grant placed at their disposal.
The disturbances appear to have commenced at
Toronto nearly at the same absolute time as at Green-
wich, and to have been generally simultaneous at both
stations. The disturbance at Toronto was at its heicht
from 11 A.M., to 4 P.M. Gottingen mean time. Its
general effect seems to have been that of causing a
decrease of easterly variation and of total intensity.
Ttse agreement in direction of the changes of horizontal
and vet tical force deserves remark : the minimum and
maximum of each occurred simultaneously, or as
nearly so as can be learned from the observations—the
minimum of both being .observed at the second read-
ing after noon, and the maximum of both at precisely
the same interval after the following midnight. The
observations of the second disturbance show a striking
connexion between the chances of declination and in-
tensity—an increase of force corresponding to an in-
crease of easterly declination, and vice versa.
An aurora was visible at Greenwich both in the
morning and evening of the 25th. At Toronto the
morning was heavily clouded, with rain, consequently
no aurora could be seen : in the evening the aurora
was visible at intervals from seven to ten P.M. Toronto
time, or one to five A.M. Gott. time, the perind of the
second great disturbance ; the remainder of the night was
heavily clouded. A gale of wind occurred on the fol-
lowing day (26th), and in the evening another (?)
aurora was seen. The extreme changes of the declina-
tion, horizontal and vertical force, during the two dis-
turbances, were as follow :—of the declination, 1 deg.
05 min. ; of the horizontal force .02436 of its whole
value ; and of the vertical force, -01288 of its whole
value. Similar observations were made at Toronto io
1840 ; and the recurrence of so great a disturbance on
the same d sy in the following year is remarkable.
At Trevandrum, in lat. 8 deg. 30 min. 35.2 sec. N.,
and long. 5 hours 7 min. 59 sec. E., au unusual mag-
netic disturbance took place simultaneously with those
observed in England and America ; although, in con-
sequence of the easterly position of 'Trevandrum, the
commencement only of the disturbance was observed
there. Tne disturbance was indicated principally by
the horizontal-force magnetometer, because the inch-
natiOn at Trevandrum being only 2 deg. 50 min., the
horizontal intensity at that station comprises nearly the
whole magnetic intensity, the vertical component being
extremely small. During the whole day of the 25th,
the horizontal intensity was weaker than the average
of the proceeding twenty-four days of the month ;
and at the Gott. hours of noon, two, four, and six,
r.m., when great disturbances were taking place at
Greenwich and Toronto, the observations at Trevan-
drum show a decrease of intensity much exceeding the
usual fluctuations. The effect of the disturbance on
the declination-magnetometer appears to have been com-
paratively small, the north end of the magnet being, how-
ever, during the whole day to the eastward of its average
position at the same hours in the preceding part of
the month.
The element principally effected at St Helena was
also the horiz :ntal force, which underwent frequent
fluctuations of unusual amount, and sustained, on the
whole, a considerable diminu:ion of intensity. Toe
magnetic inclination there being 21 deg., the horizontal
force forms by much the larger component of the total
magnetic force. The diminution took place at 10 A.m.
(25th); the intensity continued to weaken until 7 hours
42 min. 30 sec. P.m., and the loss amounted to -0118
of the whole force ; and this, it will be remarked, was
coincident with the period when the disturbances at
Greenwich and Toronto occurred. The fluctuations
of the declination at St. Helena, as at Trevandrum,
were far less striking than those of the horizontal
intensity, or than those of the declination, at Toronto
and Greenwich. The magnetic disturbances at the tro-
pical stations have not, however, always this char •cter.
The September returns from the magnetic observa-
tory at the Cape of Gond Hope (according to posteript,
dated December 29) have just arrived, and their re-
duction would occasion " an inexpedient delay in this
publication." It is satisfactory, however, to find, that
the remarkable disturbance under consideration mani-
fested itself in that southern latitude. All the magne-
toireteis were greatly affected. The greatest dis-
turbance of the horizontal force commenced about
10 A.M. (the epochs here spoken of are Go'. mean
i time) on the 25th, and attained ts extreme limit at
7b. 45m. P.M. on the same day. The vertical-force
magnetometer was deflected out of the field of view at
Eta, 30m. P.M., on the 24th, and remained so ; the in-
strument being adjusted afresh to the needle, the latter
was again deflected out of the field at 2h. 27m. 305.,
r.m., on the 25th.
For the tabular details of the observations at To-
ronto, at Trevandrum, and at S. Helena—for the pro-
jected curves of the former—and for valuable hints to
magnetic observers, we refer our readers to the publi-
cation itself; to which, it is said, the reduced observa-
tons at the Cape may form a supplement, accompanied
by observations, probably, of the same disturbance at
S mla, in the Himalaya. The September returns from
the Van Diemen's Land observatory may be expected
in February, about which time accounts may be hoped
for of the same date from Captain li.oss, R.N., who
intended to pass the last fortnight of September at
Chatham Islands, where ho would establish his magne-
tometers on shore.*

* The official account of Captain Ross': voyage, hitherto
received, has been published among the Parliamentary papers ;
and, though we have communicated the substance to our
readers some time ago, we shall insert this document in our
next, for all future reference.—Ed. Lit. Gaz.

TILL RURAL POLICE.
We perceive with great satisfaction that a strong
feeling is gaining ground in different parts of the coun-
try, and in most respectable quarters, against the con-
tinuance of the Rural Police system. It gives us the
more pleasure to see this, because it is manifestly the
r result of practical experience, not of any public agitation
of the question ; of experience, too, acquired under
circumstances which have given no scope for the de-
velopment of the worst tendencies of the system. We
have ourselves, as our readers know, always spoken of
the Rural Police Act, when we had occasion to speak
of it, in terms of reprobation ; we have assigned it a
prominent place in the catalogue of those despotic and
unconstitutional measures which alienated from the
Whigs the affections of the middle classes in England.
But there arc few subjects of public importance on
which we have more abstained from pressing or develop-
ing our views, knowing that theoretical arguments,
even though based on the soundest reason, would have,.
little effect on the public mind against an established'
institution of this nature, till the conclesions of expe-
rience should begin to co-operate with them. We
therefore reserved ourselves upon this question, under
a continual protest, till the fitting time. That time, we
are happy to say, is now rapidly approaching.
It is now but a few weeks since an attempt was
made to introduce this system into the West Riding
of Yorkshire, which singnally failed. Later still it was
repudiated after trial by the gentlemen of Nottingham-
shire. In the 'hues of Friday we published a report
of proceedings at the last. Quarter Sessions for Glouces-
tershire, in the course of which Sir John Guise gave
notice that he should move, at the very earliest period
allowed by the Act—first, for the reduction and modi-
fication, and afterwards for the total abolition, of the
new force in that county. He objected to its " enor-
mous cost and general inefficiency."
" He stated, that it was with reluctance he adverted
to the subject, in consequence of the indifferent suc-
cess which had attended his previous efforts in the way
of inducing the Magistrates to enter upon an inquiry
as to the utility of the force. He had been induced,
however, in consequence of the numerous petitions
which were about to be presented, and in consequence
of having received letters requesting his attendance, to
direct attention once more to the subject. The rate-
payers complained, and with reason, of the enor-
mous expense of the constabulary force. It was
more than double the county-rate, and it was con-
sidered that the service rendered was not at all
equal to the cost of supporting it. It was not
possible that a foot police could be efficient in widely