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XXIV. 
LEPOETS OlSr THE MAGITETIC OBSERYATIONS AT VA- 
LENTIA. Ey PROEESSOE EITZGEEALD, MA., F.E.S., 
E.T.C.D., and Mr. J. E. CTJLLUM, Meteorological Observer at 
Valentia. (Plate XV.) 
[Eead April 8, 1889.] 
liBOUT two years ago I applied for a grant towards the expense of 
establishing a magnetic observatory in Valentia to compare the changes 
\a. the magnetic elements there with those at other places. Valentia 
Isras chosen for two reasons : firstly, because it was at a considerable 
listance from other magnetic observatories ; and secondly, because the 
Leteorological observer there, Mr. Cullum, had been trained at Kew 
li making magnetic observations, and was willing and most anxious to 
pndertahe them at Valentia. During the summer and autumn of 1887 
Cr. Cullum erected a hut suitable for magnetic observations in the 
trounds of the meteorological observatory, and Trinity College lent some 
: their valuable magnetic instruments to equip it. In the accompany- 
ig Eeport Mr. Cullum has described the hut, &c., and how the observa- 
jons have been conducted. Those of this last year must be considered 
purely tentative. Eor instance, the axle and bearings of the dip 
liPcle have had to be adjusted, and the needle of the declinometer has 
id to be hardened and re-magnetized. Erom this year's observations 
[ach experience has been gained, and we hope that after a few years' 
servations it will be possible to decide whether it would be worth 
|liile erecting permanent self-recording instruments at Valentia. If 
y sensible differences exist between the changes of magnetic elements 
Kew and Valentia, it would be most important to record them sys- 
i natically, in view of the light that they may throw upon the theory 
these changes. It would be interesting to find out whether any of 
13 changes are simultaneous at Kew and Valentia, and, if not, at what 
18 they are propagated. All changes are not simultaneous, for the 
li •;ular diurnal variation must evidently be propagated at the rate of — 
1 'olution of the earth. Such observations may throw light on the 
c 3stion as to the extent to which the neighbourhood of the sea, with 
i, tides deforming the earth, affect the magnetic elements. It would 
E.I. A. PEOC, SER. III., VOL. I. K 
