Report of the Kew Committee. 



315 



sent to Messrs. Elliott Brothers, London, for the purpose of having 

 Mr. Whipple's arrangement for steadying the Collimator Magnet 

 fitted, and at the same time a rack and pinion adjustment was 

 attached to the small telescope employed in viewing the collimator 

 scale, in order to bring the scale more readily into focus. 



The values of the ordinates of the different photographic curves 

 determined in January were as follows : — 



Declination : 1 inch=0° 22''04 1 cm.=0° 8'7. 



Bifilar, January 13, 1885, for 1 inch £H =00268 foot grain unit. 



„ 1 cm. „ =0-0005 C.G.S. unit. 

 Balance, January 14, 1885 „ 1 inch oV=0'0280 foot grain unit. 



„ 1 cm. „ =0-0005 C.G.S. unit. 



Information on matters relating to terrestrial magnetism and 

 various data have been supplied to Dr. Wild, Professor Mascart, 

 Dr. Van der Stok, Mr. R. H. Scott, Professor W. G. Adams, Dr. Rijcke- 

 vorsel, Professor Riicker, and Dr. Atkinson. 



The monthly observations with the absolute instruments have been 

 made as usual, and the results are given in the tables forming 

 Appendix I of this Report. 



The following is a summary of the number of magnetic observations 

 made during the year : — 



Determinations of Horizontal Intensity 34 



,, Inclination 127 



„ Absolute Declination 53 



International Polar Commission. — The magnetic observations made 

 during the year September, 1882, to August, 1883, at Fort Rae, North 

 America, by the expedition under Captain Dawson, R.A., have been 

 fully reduced and prepared for publication, on the plan adopted by 

 the International Polar Commission at their Meeting at Vienna in 

 3884, by the Observatory staff during extra office hours, and the 

 work is at present passing through the press. The readings of the 

 Kew Magnetographs have also been reduced on the same plan at the 

 cost of the Polar Committee of the Royal Society, and copies 

 forwarded to Dr. H. Wild, President of the Commission. Special 

 scales were constructed for the tabulation of the Kew curves on the 

 C.G.S. system by Mr. Baker, the magnetic observer. 



Krakatoa Eruption. — The Krakatoa Committee of the Royal 

 Society having entrusted to the Kew Committee the data which 

 they have collected relating to electrical and magnetical phenomena 

 which occurred about August 27, 1883, the date of the eruption of 

 Krakatoa, the curves of the magnetographs of the Observatories at 



