KEPORT OF THE KEW COMMITTEE. liu 



but these phenomena will, it is hoped, be investigated before the time whcii 

 the Observatory ceases to be connected with Ihe British Association. 



The curves are as yet all in good order. The whole expense of preserving- 

 traces would probably not much exceed .£100. And I would suggest that I 

 might with propriety direct to this object a grant of .£100 which I have at 

 present in hand from the Eoyal Society for procuring impressions of mag- 

 netic curves. 



(h) Hourly Tuhvlations from Traces. 



The documents next in order are the hourly tabulated numerical values, 

 as exhibited in monthly tables for each of the elements. Although indi- 

 A'idual results of this nature have been published by Dr. Neumayer, the cost 

 of the piiblication of the Kew series in this country would be very great ; 

 and bearing in mind tlie limited reference to such individual results, I would 

 suggest that a carefully preserved manuscript record would probably be suf- 

 ficient. 



(c) Separation of Disturbances and Solar-Diurnal Variations. 



Pursuing the method indicated by Sir E. Sabine, and adopting the sepa- 

 rating value finally determined by him, we should obtain monthly results 

 indicating the following points for each of the three elements, distributed 

 according to the hour of the day : — 



1. Aggregate of disturbances tending to increase the numerical values. 



2. Aggregate of disturbances tending to diminish the same. 



3. Solar-diurnal range of the undisturbed observations. 



I would suggest that the monthly results embodying these facts should 

 be published in detail. The publication Avould not probably occupy more 

 than thirty-six quarto pages well filled with figures. 



Lunar-Diurnal Variations. 



Adopting Sir E. Sabine's method of treating these, I would suggest, in 

 addition, a classification according to the relative position of the sun and 

 moon. We might perhaps have quarterly means of lunar days, each quarter 

 being divided into four groups representing the four well-known relative 

 positions of the sun and moon. 



This might occupy about fifteen quarto pages well filled with figures. 



(d) Secidar C]ian(/e and Semiannual Inequality. 



Presuming that these elements are best determined for the two compo- 

 nents of magnetic force from the absolute observations, I would suggest that, 

 as regards the declination. Sir E. Sabine's plan be pursued. As he has al- 

 ready given the details of his results up to the end of 1863, it would only be 

 necessary to continue these up to the time when the series is complete. 



Remarlcs on the ahove. 



If a condensed series of results be published as above, and if, in addition, 

 the traces and hourly observations be preserved, as is suggested, future theo- 

 rists would have a large and valuable source of information by which to test 

 their speculations. I should be happy, had I the opportunity of using such 

 a series, to discuss it after the manner that Sir E. Sabine has indicated in 

 the very valuable papers which he has presented to the Royal Society. 



