88 



Report of the Kew Committee. 



3rd. Solar observations. 



4th. Experimental, in connexion with any of tbe above depart- 

 ments. 



5th. Verification of instruments. 

 6th. Miscellaneous . 



I. Magnetic Observations. 



The Magnetographs have been in constant operation throughout 

 the year. 



The values of the ordinates of the different photographic curves 

 determined in January were as follows : — 



Declination : 1 inch=0° 22'*04. 1 mm. = 0° 0'*87. 



Bifilar, January 9, 1883, for 1 inch <5H= 0*0221 foot grain unit. 



„ 1 mm. „ = 0'0004 mm. mgr. unit. 

 Balance, January 12, 1883 „ 1 inch cV=0*0376 foot grain unit. 



,, 1 mm. „ =0*0007 mm. mgr. unit. 



It having been decided to attempt to re-adjust the Bifilar and 

 Vertical Force instruments so as to bring their scales more closely in 

 accordance with the generally adopted values, the necessary altera- 

 tions were made in the adjustments, and on redetermining the scale 

 values on January 17th the following results were obtained: — 



Bifilar for 1 inch £H = 0*0277 foot grain unit. 



,, 1 mm. ,, = 0*0005 mm. mgr. unit. 

 Balance „ 1 inch 8V = 0*0261 foot grain unit. 



1 mm. ,, =0*0005 mm. mgr. unit. 



The tabulation of the traces of the three elements was temporarily 

 suspended at the conclusion of the year for which the observations 

 were promised to the International Polar Commission. Attention is 

 now being devoted to the revision and reduction of the results. 



A common gas-jet has been substituted in the Vertical Force 

 instrument with advantage for that formerly employed, but on trial the 

 results obtained by a similar substitution in the case of the other 

 instruments were not satisfactory, and the old burners with chimneys 

 are retained for the present. 



Gelatino-bromide paper has been used for all three instruments 

 with great success and economy of time throughout the whole year, 

 and an examination of the curves shows that not a single hour's trace 

 has been lost since its adoption, from purely photographic causes, 

 rapid and minute movements of the needles being recorded. 



Several magnetic storms have been observed, the principal being 

 that of November 17th and 18th, 1882, which, together with its 

 accompanying aurora and meteor, excited considerable attention. 



