' 
NA 
In a letter to you last week Mr. W. H. Preece called attention 
to a sudden appearance of earth-currents on the 19th between 
10.15 and 10.20 p.m. G.M.T., traces remaining until 10.50. A 
magvetic storm was in progress at the time, and had commenced 
shortly after 4 p.m. The declination magnet moved at first 
slightly towards the west; but the most rapid movement was 
towards the east, and commenced at 9.40, attaining its absolute 
minimum, or greatest E. elongation, at 10.9. It then returned 
as. rapidly westward until 11 p.m., but the absolute westerly 
maximum was only reached at 6.50 the next morning. The 
whole range of the declination maguet was 53'*o. 
The H.F. magnet was not much disturbed, but the chief 
irregularities occurred between 9.50 and 10.55. 
The V.F. magnet showed more clearly the action of the dis- 
turbing force, with a maximum at 7.45 p.m., and a minimum at 
3.40 the next morning. The V.F. magnet was tremulous 
between 10.0 and 10,40 p.m., with a slight misimum at 10.15. 
S. J. Perry 
Stonyhurst Observatory, Whalley, January 29 
THE magnetographs at this obervatory registered a small 
magnetic disturbance during the evening and night of January 
19, which lasted over an interval of tine considerably greater 
than the earth-currents observed by Mr. Preece. 
The magnets were toleraily quiescent until about 4.35 p.m. 
G.M.T., when the declinometer became disturbed, and the 
bifilar indicated a gradual diminution of horizontal force, 
vertical force at the same time increasing. The latter attained 
its maximum deviation from the average value at about 8.0 p.m., 
whilst the horizontal intensity indicated its lowest at the same 
time. The declination after slightly rismg, however, continued 
to dimini-h, and between 9,30 and 10.15 p.m. it became re- 
duced 20°7 minutes of arc. Between 10.15 and 11.0 it rapidly 
moyed in the contrary direction 190, after which it gradually 
rose to a position of maximum at 6.50 a.m. on the twentieth, 
when the needle stood about 10’ to the westward of its normal 
position at that hour. From that point it gradually fell away, 
rp after 11.45 a.m. it only oscillated slightly about its usual 
place. 
The movement between 9.30 and 11 p.m. of the bifilar indi- 
cated an augmentation of iutensity followed by an equally 
abrupt fall, whilst the vertical-force instrument showed that 
component of terrestrial magnetism to have been but slightly 
affected. 
As is usual in such cases the abrupt disturbance, or as it is 
called from the aspect of the curves, the peak, under notice was 
repeated or echoed on several ubsequent days, 
On the 20th, about half an hour after midnight very faintly, 
on the 2{st it was stronger, and vccurred between 9.20 and 9.50 
p-m. On the 22nd between 7.50 and 9.40 p.m., its extent then 
being to’, and finally on the 23rd, from 9.0 to 10,10 p.m., show- 
ing then about the same amount. 
The daily weather charts for the 20th report bright aurora 
seen on the 19th in Scotland and Norway. 
Kew Observatory, January 30 G, M. WHIPPLE 
REFERRING to Mr, Preece’s letter of the 24th inst., it may be 
interesting to note tht in the Daily Weather Chart for the 2oth 
inst. bright aurora is recorded as having appeared in North-West 
Europe on the evening of the 19th, the day when the earth- 
currents were observed. J. PARNELL 
Upper Clapton, January 30 
Variations in the Sun’s Heat 
ALL lovers of science, and more especially those devoted to 
the study of atmospheric physics, wust rejoice to learn that the 
Government of India has sanctioned Mr. Blanford’s proposal to 
send a properly qualified observer with good instruments to Leh, 
for the purpose of directly measuring the sun’s heating power 
from day to day. : 
Meanwhile, as we sball have to wait for another decade before 
it can be settled with any certainty, how much, and in what way 
the stn’s heat varies, ic miy be as well to notice the latest and 
hitherto most valuable indirect evidence, furnished with respect 
tu this question by India. 
That country bas Jong been regarded as exceptionally well 
placed for reflecting in its meteorological phenomena with com- 
paratively little complexity the secul ir changes ia solar radiation, 
Py 
URE 
and the only drawback hitherto, has been the lack of good and 
continuous observations over a large area. This has now been 
remedied by the excellent organisation introduced by Mr. Blan- — 
ford, by which the observations made at upwards of 100 regular 
observatories and more than 350 rainfall stations, are collected 
and discussed at one central office, and published in one volume. ~ 
With these it is possible to arrive at average results, in which 
local variations are eliminated, and which may be accepted with 
confidence as representing the general conditiuns over the whole 
area. Ina recent Proneer Prof. Hill gives the following table of ; 
the abnormals in the chief meteorological elements for the whole 
of India during the past few years, which, if indirect evidence is 
to be trusted, most decidedly favours the hypothesis Prof, Hill 
and myself have all along regarded as the best working hypo- 
thesis, viz. that the sun radiates most heat to the earth in the 
years of fewest spots. 
Variations of certain Meteorological Elements from their mean 
Values 
Excess 
temperature Annual Mean pressure Mean pro- Mean 
Year. of black mean air of water rtion of annual 
bulb ther- temperature. vapour. cloudy sky. rainfall. 
mometer. sd 
5 ° “ Tenths. “ 
1875 - "76 —'29 — "004 — "03 +3°66 
1876 — "33 —*o8 — "O17 — ‘20 — 4°37 
1877 +°19 areets} + OIL +°31 —2'97 
1878 +°44 + "62 +*020 + "09 + 5°66. 
1879 — “36 —"13 — ‘O14 =" +197 
Prof, Hill appends the following remarks to this table :— 
“The radiation, as measured by a thermometer with a { 
blackened bulb, rose gradually until 1878, and then fell off in 
intensity ; the temperature of the air, which seems the next : 
simplest and most direct effect of the sun’s heat among those given 
in the table, also increased until 1878, and then diminished ; the 
vapour tension and cloud—-more remote effects— show a similar, 
but not so closely coincident variation, and finally, the rainfall, 
the most distant effect of all, appears to lag just about a year 
behind ; for observations made before the comusencement of Mr, 
Blanford’s reports for all India indicate that there was a wave of 
heat in 1873-74, immediately preceding the cold period at the 
top of the table.” 
Now while there is no doubt, as Mr. Blanford has. recently 
shown in the Yournal of the Asiatic Society of Bengal, and 
elsewhere, that the temperature at the earth’s surface is veryde- 
cidedly influenced by rainfall and cloud, we see from this table _ 
that the year of highest temperature was actually that in which 
most rain fell, and Prof Hill has found that the excesses of tem- 
perature and rainfall, though not strictly contemporaneous, were 
most decided in the same regions of the country. It is scarcely : 
necessary perhaps to add that the actual sun-spot minimum 
occurred in the middle of 1878, in order to show the important 
bearing of these facts on our hypothesis. 
Tunbridge Wells, January 24 E. DouGLas ARCHIBALD, 
Solar Observations 
I INCLOSE two letters which I have recently received from 
Mr. W. A. Holland, chief officer of the ship Sarah Bell, and 
which I think will interest your readers. It is to be hoped that ~ 
other observers, whether on land or sea, may have important 
information to communicate on the subject, which they may be 
induced to give you for publication, WILLIAM THOMSON 
‘Lhe University, Glasgow, January 23 
Havre, January 10, 1882, Ship ‘* Sarah Bell” 
S1r,—Being at Sea last November 22 and 23, and our posi- 
tion at noon being lat, 18° 58’ S., long. 1° 53’ W., aud lat. 17° 
32' S., long. 3° 39' W. respectively ; and while observing the 
sun’s meridian altitude, I noticed a very remarkable dark spot 
on the sun’s dise ; it was about one-third of the sun’s diameter, 
and bearing south-east from © centre, On the following day it 
appeared one-fourth of © diameter, and of bearing west-north- 
west from centre; by putting down the proper shades of jmy, 
sextant I could see it very distinctly. 1 called the captain’s. 
attention to the fact at the time, and he says he never saw such 
a phenomenon in his life ; he is a gentleman who has spent his 
life at sea since the year 1840, Almost at the same time I read 
from the June number of Good Words for 1879 your very valu- 
able article on Terrestrial Magnetism and the Mariner’s Compass ; 
but the latter part of the article treating on sun-spots caused me 
to take this bold step of addressing you, trusting | have not been 
