116 



Report of the Kew Committee. 



The monthly observations with the absolute instruments have been 

 made regularly, and the results are given in the tables forming- 

 Appendix I of this Report. 



The Sub-Committee, appointed to consider the best means of 

 utilising the records of the magnetographs, as mentioned in the 

 Report for 1878, reported that it was unadvisable, in their opinion, 

 to proceed with the regular tabulation of the curves, and suggested that 

 attention should rather be directed to their comparison with synchro- 

 nous curves, taken at other magnetic Observatories in different parts 

 of the globe, in order to ascertain whether similar disturbances occur 

 at these several stations, and at what time intervals ; with a view to 

 the development of the theory of magnetic disturbance. 



In order to carry out this scheme, a circular, inviting co-operation 

 on the part of observers provided with magnetographs of the Kew 

 pattern, was issued to the Directors of the following Observatories : — 

 Batavia, Bombay, Brussels, Coimbra, Colaba, Lisbon, Mauritius, 

 Melbourne, Potsdam, St. Petersburg (Pawlowsk), San Fernando, 

 Stonyhurst, Utrecht, Vienna, and Zi-Ka-Wei. Replies favourable to 

 the project were received from all those whose instruments were 

 working under satisfactory circumstances. 



An examination of the records for the year 1879 indicated the 

 month of March as that most suitable for the purpose of the com- 

 parison. Accordingly, a further request for copies of the declination 

 curves for that month was issued, and, in response, they have at 

 present been received from : — 



Coimbra, Colaba, Lisbon, Melbourne, St. Petersburg, Stonyhurst, 

 Vienna, and Utrecht. 



The comparison of these magnetic curves has been undertaken by 

 Professor W. Grrylls Adams, who has already communicated to the 

 Swansea Meeting of the British Association a preliminary account of 

 the principal facts which have as yet come to light. The discussion, 

 which is still in progress, cannot be completed until data from the 

 more distant stations, as well as the horizontal and vertical force 

 curves from all stations for the same month, have arrived. 



The Observatory has also received curves from several of the foreign 

 Observatories, showing the variations recorded by their instruments 

 during the progress of the magnetic storm already referred to. 



By the kindness of Professor Gr. Carey Foster, some experiments were 

 made at the laboratory of University College, London, with a view to 

 determine whether the magnetisation of dip-needles could be con- 

 veniently effected by means of a coil of wire conveying an electric 

 current, thereby avoiding certain defects due to their magnetisation 

 by bars, after the ordinary method. The results of these experiments 

 proved that the requisite magnetic intensity could be easily imparted 

 in the way referred to. 



