538 



SCIENTIFIC NEWS. 



[June 8, i88S. 



ef the wires of the transit instrument, as seen by 

 reflection from a trough of mercury). The result 

 showed that tremor from trains in the tunnel between 

 Blackheath and Charlton (about a mile distant) caused 

 the image to disappear ; and as the proposed tunnel was 

 to pass within 570 yards of the instrument, the Govern- 

 ment opposed the Bill, and the Blackheath route was 

 abandoned. 



With one or more of the equatoreals, twenty-four 

 occultations of stars by the moon double the average of 

 the preceding seventeen years, eighteen phenomena of 

 Jupiter's satellites, and three comets (on twelve nights) 

 have been observed In common with many directors 

 of observatories, the Astronomer-Royal has to lament the 

 fact that clouds almost set at naught his elaborate 

 arrangements (with nine instruments) for securing obser- 

 vations of the small stars occulted during the lunar 

 eclipse of January 28th last. 



The Sheepshanks equatoreal has been devoted to 

 experiments in stellar photography, to determine the 

 extent of field available on curved and plane plates. The 

 experiments show that the advantage derived from the 

 use of curved plates is very doubtful, and that the images 

 on plane plates are good enough as far as two degrees 

 from the centre. 



With the spectroscope attached to the izf in. equa- 

 toreal, ^;^^ measures have been made to determine the 

 rate of recession or approach, in the line of sight, of six- 

 teen stars ; and certain stars have been observed for Mr. 

 Lockyer. 



Photographs of the sun were obtained on 205 days of the 

 356 ending May loth. For the year 1887, supplementing 

 the Greenwich series by photographs taken in India and 

 the Mauritius, a record of the sun's surface has been 

 secured on 361 days. The reduction of the measures of 

 these photographs is complete, and the results ready for 

 the press. 



In the magnetic department the continuous registration 

 of the changes of magnetic declination, horizontal force, 

 and vertical force has been maintained, a duplicate set of 

 photographs being taken since January last, so that one 

 set may be available for persons wishing to discuss Green- 

 wich records. Five measures of resistance of the earth- 

 current wires gave very discordant results ; in fact, these 

 wires have not yet recovered the effects of the snowstorm 

 of December, 1886, and it seems hopeless to attempt to 

 express the measures of ordinates on the photographs in 

 terms of the electrical units, until the conditions of the 

 circuits have been improved. It is thought that a slight 

 dislocation in the trace soon after sunset, and a sudden 

 return to original position just before sunrise, which 

 increase the difficulties above referred to, are connected 

 with the electric lights in the vicinity of the earth plate 

 at Angerstein's wharf. It may be remarked here that 

 the Observatory is dependent on the courtesy of the 

 South-Eastern Railway Company for carrying the earth- 

 wires. 



The meteorological records for the year 1887 show that 

 the mean temperature was 47'8 degrees, or i'5 degree 

 below the average of the preceding 46 years. The highest 

 temperature was 92-2 degrees on July 4th, and the lowest 

 I5'5 degrees, on January 2nd. The number of hours of 

 bright sunshine was 1,401, or 190 above the average of 

 the preceding ten years. The rainfall was I9'9 inchej, 

 berng 4-8 inches below the average of the preceding 46 

 years. 



The Greenwhich time-ball was dropped regularly except 



on four days of very high wind ; the Deal ball except on 

 eight days, on six of which the telegraphic connexions 

 were interrupted. Automatic signals have been received 

 to check the errors of the Westminster clock and that used 

 to drop a time-ball at Devonport. The error of the 

 former was less than i sec. on 25 per cent, of the days 

 of observation, and amounted to 4 sees, on only 2 per 

 cent. 



The report concludes with the following remarks by 

 Mr. Christie, which excited much comment among the 

 visitors : — 



" In my last report it was suggested that the instru- 

 mental equipment of the Observatory should be supple- 

 mented by a photographic refractor of thirteen inches 

 aperture (equatoreally mounted) to enable Greenwich, 

 as the National Observatory, to take its share in the 

 scheme for forming a photographic map of the heavens, 

 and for thus extending our knowledge of the places of the 

 fixed stars. Consequent on the resolution of the Board 

 of Visitors at the last visitation I brought this question 

 of the insufficiency of our instruments for the present 

 wants of astronomy to the notice of the Admiralty and of 

 the Chancellor of the Exchequer, and the matter is still 

 under the consideration of the Government. If the 

 Royal Observatory is to take part in this work of carrying 

 out one of the principal objects for which the Astronomer 

 Royal was appointed, it appears to be essential that a 

 decision should be arrived at without delay, in view of 

 the circumstance that thirteen observatories (including 

 those of Melbourne and Sydney in our own colonies) 

 have already ordered their instruments, which are to be 

 completed by the end of the present year. 



" Allusion was made in the last report to the increased 

 demands made on the Observatory in recent years both 

 by the scientific and the general public, and in view of 

 the consequent development of work it now becomes 

 necessary to review the position of the establishment, 

 which was constituted many years ago, when the con- 

 ditions were very different. In order to understand the 

 difficulty of the present situation it is necessary to bear 

 in mind the following facts : — In 1835 there were five 

 assistants (excluding the chief assistant) having no com- 

 puters to superintend, no extraneous work beyond the 

 care of a relatively small number of chronometers for the 

 nav}', no magnetic and meteorological observations, no 

 altazimuth observations, no spectroscopic and photo- 

 graphic observations. At the present time there are 

 eight assistants (excluding the chief assistant) having 

 fifteen computers to superintend, and of this staff two 

 assistants are absorbed by the magnetic and meteoro- 

 logical branch, one by the altazimuth, and two by the 

 spectroscopic and photographic branch, leaving only three 

 assistants to do the astronomical work, which in 1835 

 required five assistants, and in addition to perform all the 

 extraneous duties which the Astronomer Roj'al has felt 

 it desirable to undertake in the public interest. 



"Under these circumstances it becomes a matter for 

 serious consideration whether, unless adequate provision 

 be made for the primary objects of the Observatory, 

 extraneous work, such as the supply of time-signals, may 

 not have to be dropped. The service of hourly time- 

 signals throws considerable work on myself and the staff 

 of the Observatory, and, as it is purely voluntary, it 

 appears to me that a condition of its maintenance must 

 be that arrangements shall be made to enable the proper 

 work of the Observatory to be carried on and suitably 

 developed." 



