3 3 8 



NATURE 



\_June 7, 1883 



•Committee, so that a record of the condition of the sun on 279 

 out of the 302 days in that interval is now presented. From 

 1882 October 20, eight-inch photographs were taken in India, 

 and fur the measurement of these a special micrometer has been 

 ordered of Messrs. Troughton and Sirnms by the Solar Physics 

 Committee. 



" All the photographs received from the Solar Physics Com- 

 mittee have been measured in duplicate, and the measures have 

 been completely reduced so as to exhibit heliographic longitudes 

 and latitudes of spots, and areas of spots and faculse, from 18S1, 

 December 22, to 1882, October 19, the end of the series of four- 

 inch photograph-. 



" Magnetical Observations : — 



" The course of ob-ervation continues the same as in former 

 years, changes in the magnetic declination, horizontal force, and 

 vertical force being continuously recorded by photography with 

 the three magnetometers, whilst absolute values of magnetic 

 declination, dip, and h uizontal force are found by eye observa- 

 tion. Earth-currents in two directions nearly at right angles to 

 each other are als 1 photographically registered. 



" A great improvement lias been made in the photographic 

 registntion by the substitution in June last of Morgan and 

 Kidd's argentic-gelatino-bomide paper with ferrous oxalate 

 development for the old photographic process. 



"The large temperature correction of the vertical force 

 magnet has been reduced to less than one-fourth of its former 

 amount by some alteration- which were carried out by Mr. Simms 

 last autumn. The effect of these alterations has been to reduce 

 the correciion for change of 1° Fahrenheit from o '00088 of the 

 vertical force to about 000020. The coefficient, ha<, however, 

 still the opposite sun to that which would result from mere loss 

 of magnetic power with increase of temperature. It is intended 

 to make an attempt to still further diminish the temperature cor- 

 rection by shifting the magnet in its carrier so as to reduce the 

 horizontal stalk and balance weight. 



" It was remarked in the last Report that the earth-current 

 registers frequently showed abnormal disturbance during rain. 

 By the kindne s of Mr. I.emard (the succe-sor to the late Mr. 

 •C. V. Walker, as telegraph engineer of the South- Eastern Kail- 

 way), the wires were repaired in February, and the rain disturbance 

 seems now to have disappeared. 



" The following are the principal results for magnetic elements 

 for 1SS2:— 



Approximate mean westerly 

 declination 



Mean horizontal force 



Mean dip 



1 8° 22'. 

 /3'9 J 3 ( m English units). 

 " \ I '804 (in metric units). 



67 33 33 (by 9-inch needles). 

 67 34 34 (by 6-inch needles). 

 67 34 14 (by 3-inch needles). 



" There has been considerable magnetic activity during the 

 year, the month of November, which was characterised by the 

 appearance of a very large sunspot, being particularly disturbed 

 with remarkable magnetic storms on November 17, 19, and 20, 

 > and many interesting cases of lesser disturbance. The magneti- 

 cal changes in November are so interesting in relation to the 

 accompanying outburst of sunspots that it seems desirable to 

 have the registers for a great part of the month as well as for 

 other days of magnetic disturbance in the year lithographed in 

 the 'Greenwich Magnetical Results for 1882' on a reduced 

 scale. The character of a disturbance would, ] think, be much 

 better shown by a reproduction of the curves traced on thf 

 photographic sheets than by tables of numerical values oe 

 ordinates. I am making inquiries as to the practicability of 

 using some anastatic process, which would not be very expensive. 



"The magnetic disturbances on October 2 and November 17 

 were accompanied by brilliant auroras. 



" Particulars of magnetic disturbances are regularly communi- 

 cated to the Colliery Guardian newspaper for the information of 

 mining surveyors. 



" Meteorological Observations : — 



" On the occasion of the gale of 1882, October 24, a velocity 

 of 64 miles an hour was registered with Robinson's anemometer 

 for two successive hours, being greater than any velocity pre- 

 viously recorded here, but the greatest pressure registered with 

 the chain was only 29 lbs on the square foot, whilst on 1882, 

 April 29, a pressure of 494 lbs. was recorded with the copper wire 

 at a time when the velocity was only 50 miles an hour. 



" The observations of temperature of the Thames have recently 

 been resumed under the charge of the Corporation of London, 

 who have instructed Mr. G. J. Symons*to arrange details. The 

 observations are now made at the e id of one of the jetties of the 

 Foreign Cattle Market at Deptford, where a record is to be kept 

 (by means of two Six's thermometers) of the daily maximum and 

 minimum temperatures of the Thames at a depth of 2 feet below 

 the surface, and also near the bottom of the river. Mr. Symons 

 has arranged that these observations shall be regularly communi- 

 cated to the Royal Observatory to be included in the meteoro- 

 logical tab e published weekly in the Ke dstrar-General's Reports. 



" The mean temperature of the year 1S82 was 49°'6, being 

 o°'l lower than the average. The highe t air temperature was 

 8l°'o on August 6, and the lowest 22°'2 on December II. The 

 mean monthly temperature was above the average from January 

 to May, then below until September. In October, November, 

 and December it differed little from the average. 



" The mean daily motion of the air in 1882 was 306 miles, 

 being 27 miles greater than the average For the month of 

 November the mean daily mo'ion was 449 mile-, being 159 

 miles above the average. The greatest daily motion was 758 

 miles on November 4, and the lea t 30 miles on December II, 

 As already mentioned, the greatest hourly velocity was 64 miles 

 an hour, and the greatest pressure (with the chain) 29 lbs. on 

 October 24. 



"During the year 1882 Osier's anemometer showed an 

 excess of 11 revolutions of the vane in the positive direction 

 N., E., S., W., N., if all th* turnings are counted (as has been 

 the practice in former years) ; or of 23 revolutions in the 

 positive direction if the turnings which are evidently accidental 

 are excluded. 



" The number of hours of bright sunshine recorded by Camp- 

 bell's sunshine instrument during 18S2 was 1245, which is more 

 than 40 h >urs above the average of the 5 preceding years. 



"The rainfall in 1S82 was 25-2 inches, being very slightly 

 above the average. 



"The Westminster clock has maintained its high character, 

 its errors having been under Is. on 66 per cent, of the days of 

 observation, between Is. and 2s. on 25 per cent., between 2S. 

 and 3s. on 6 per cent., and between 3s. and 4s. on 3 per cent. 

 The error has never exceeded 4s. 



Mr. Christie concludes as follows : — 



" The changes suggested in the la>t Report have been carried 

 out, and will, I trust, tend to increase the efficiency of the 

 Observatory. The restriction of the altazimuth observations of 

 the moon to the semi-lunation from last quarter to first quarter 

 has enabled u- to devote more attenti m to equatoreal observations, 

 though the results hitherto obtained have been somewhat limited 

 through the inadequacy of our instrumental means. The pre- 

 sentation of the Lassell telescope has now removed this difficulty, 

 and when this fine instrument is in working order we may 

 hope to be able to take up with success observations of 

 comets, faint satellites, and other objects of interest. In regard 

 to the spectroscopic observations we have now two observers 

 available, and it may be expected that in the coming year we 

 shall reap the full benefit of the arrangement by which Mr. Nash 

 takes a share in this work. 



" In solar photography we have undertaken the measurement 

 and reduction of Indian photographs, supplementing those taken 

 at Greenwich from the commencement of 1882. The Solar 

 Physics Committee propose to undertake the arrears of this 

 work for preceding years. 



" In some slight degree the past year has been one of tran- 

 sition and of preparation for future work. Some administrative 

 changes have been made, and the observers have been gaining 

 experience in some new directions ; but the regular cour-e of 

 observation and reduction has not been disturbed, and it has 

 been my special endeavour to maintain the standard meridian 

 observations in full vigour — a task in which I have received the 

 hearty cooperation of all the staff. 



" In regard to the coming year, I may mention one special 

 work of meteorological reductions which it seems desirable to 

 take in hand. The hourly ordinates of barometer and thermo- 

 meter registers have been read out and tables of mean values 

 formed for the 20 years of the meteorological reductions, and also 

 year by year since 1877 ; but there is a gap of three years for the 

 barometer (1874-1876), and of 8 years for the thermometer 

 (1869-1876), for which the photographs have not been dis- 

 cussed. The continuity of the Greenwich series is thus broken, 

 and the results are not available to their full extent. The dis- 



