124 
NATURE 
[Fune 10, 1886 
rent changes for 1° of temperature being expressed in 
terms of the horizontal force and vertical force respect- 
ively :— 
For x Fahr. increase of temperature 1868 1885 1886 
Apparent decrease of horizontal force ‘ooo18 ‘00026 ‘oo02I 
1882 1885 1886 
Apparent increase of vertical force ... "09020 ‘00022 00020 
The following are the principal results for magnetic 
elements for 1885 :— 
18° 2' west. 
{ 3°9376 (in English units). 
“| 3°8156 (in metric units). 
Approximate mean declination 
Mean horizontal force... 
(67 27 28 (by 9-inch needles). 
... 467 27 32 (by 6 inch needles), 
Mean dip 
( 67 28 27 (by 3-inch needles), 
In the year 1885 there were only three days of great 
magnetic disturbance, but there were also about twenty 
days of lesser disturbance for which it may be desirable 
to publish tracings of the photographic curves. It is 
proposed to add tracings of the registers on four quiet 
days to serve as types of the ordinary diurnal movement 
at four seasons of the year, as was done for 1884. 
The automatic drop of the Greenwich time-ball failed 
on two days during the past twelve months, on one oc- 
casion through accumulation of snow on the mast, and on 
another through failure in the clock-work apparatus for 
daily reversal of the currents through the electro-magnets. 
This apparatus has since been removed, and the direction 
of the currents is now reversed by hand once a week. On 
one day the ball was not raised on account of the violence 
of the wind. 
As regards the Deal time-ball, there have been seven 
cases of failure owing to interruption of the telegraphic 
connections, and on three days the violence of the wind 
prevented the raising of the ball. There nave been 
three cases of failure of the 1 p.m. signal to the Post 
Office. 
No further action has been taken as regards the esta- 
blishment of hourly time-signals at the Lizard or Start, as 
the arrangements for preliminary trial of a collapsible cone 
at Devonport are not yet completed. One of the Transit 
of Venus clocks (Dent 2010) has been adapted by Messrs. 
E. Dent and Co. to give hourly time-signals, and to be 
synchronised bythe help ofan auxiliary seconds’ pendulum 
on the plan I proposed in the last report. 
The longitude of Gibraltar was determined last year 
under Capt. Wharton’s direction, by exchange of tele- 
graphic signals on August 8, 9, and 12 between Green- 
wich and Gibraltar, the Eastern Telegraph Co. having 
courteously given the free use of their telegraph cable for 
the purpose. The signals were transmitted by relay- 
action from the ends of the cable to the observing-stations 
at Greenwich and Gibraltar. Local time was determined 
at Gibraltar by the officers of H.M.S. Sy/véa with the 
sextant, and at Greenwich by Commander Moore and 
Lieut. Douglas by means of sextant observations, and also 
~by transits with the transit-circle. In connection with this 
determination a large number of observations of signals 
were made at Greenwich for the determination of the 
personal equations of the different observers in observing 
telegraph signals. At Greenwich the longitude signals 
were observed by five observers independently. Com- 
mander Moore and Lieut. Douglas made a series of 
observations at Greenwich last summer for comparison 
of the relative value of determinations of local time made 
with a sextant and with a small transit instrument 
respectively. 
The record of the past year shows that the work in all 
branches tends to increase. This increase could not well 
be resisted without impairing the efficiency of the Ob- 
servatory, but year by year it causes more pressure on 
our limited staff, which, in addition to scientific work, is 
charged with the ever-increasing duties of a Government 
Office. In this connection I may mention that a good 
deal of my own time, as well as that of the Chief 
Assistant, has Jately been occupied with various matters 
connected with the Navy, reference having been made 
to me on the subject of gun-directors, mirrors for electric 
search-lights, and binoculars, in all of which there are 
involved questions requiring careful consideration. 
Commencing with the year 1885, Greenwich civil time, 
reckoning from midnight to midnight and counting from 
o to 24 hours, has been adopted in the spectroscopic 
and photographic results as well as in the magnetical and 
meteorological. It is proposed to defer the introduction 
of this time-reckoning into the astronomical results till 
the year 1891, for which year the Board of Visitors have 
recommended its adoption in the Waztical Almanac. - In 
an Observatory such as this, where observations of various 
classes are carried on, there is, however, considerable 
inconvenience in the retention of the present astronomical 
day, which now involves the use of two systems of reckon- 
ing mean solar time in the same establishment. 
The construction of an object-glass of 28 inches aper- 
ture and of 28 feet focal length, with suitable tube, to be 
mounted on the south-east equatorial, has been authorised 
by the Government, and the necessary funds have been 
provided in the estimates. The work has been intrusted 
to Mr. Grubb, with whom I have arranged the details of 
the tube, which is to be of special construction, adapted 
to the conditions of the mounting, and available for 
spectroscopy and photography as well as for eye-observa- 
tions. Mr. Grubb proposes to provide means for readily 
separating the lenses of the object-glass to such a distance 
as will give the proper correction for photographic rays. 
Messrs. Chance are engaged in the manufacture of the 
glass for the lenses, and have already made a flint disk 
which promises to be very satisfactory. 
In view of the recent development of astronomical 
photography, I propose to have constructed, for use with 
the present 12}-inch refractor of the south-east equatorial, 
a combination of a convex flint and concave crown lens, 
which, when placed about 2 feet within the focus, would 
correct the chromatic aberration of the object-glass for 
the photographic rays without alteration of the focal 
length. If this plan succeeds, the instrument would then 
be well adapted for photography, thanks to the firmness 
of its mounting and the excellence of its driving-clock. 
THE PAST WINTER 
Ae the meeting of the Royal Meteorological Society 
held on May 19 a paper was read on ‘“ The Severe 
Weather of the Past Winter, 1885-86,’ by Mr. C. 
Harding, F.R.Met.Soc. The paper dealt with the six 
months from October to March in a general way, and 
with the three months from January to March more in 
detail, as the latter embraced the period during which 
the weather was most severe, and in which both frost and 
snow were exceptionally prevalent. The material used 
in the discussion was for the most part contributed by 
the kindness of the Meteorological Council. 
The greatest deficiency of temperature throughout the 
winter occurred in the weeks ending January 25, March 
1, 8, and 15, the defect on the average amounting to as 
much as 9° and 10° over the greater part of England. 
During the fortnight ending March 15 the mean tempera- 
ture was below the freezing-point in the Midland Counties 
and in the north-west of England, and, considering the 
British Islands as a whole, the temperature was lower 
during this fortnight than in any similar period of the 
winter. The means for each of the six winter months 
show that the temperature was below the average over 
the whole Kingdom in October, January, February, and 
March. In the east, south, north-west, and south-west 
of England, and the Channel Islands, as well as over the 
