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II. Observations on the diurnal variation of the magnetic needle , 
the Whale Fish Islands , Davis’s Strait. By Lieutenant 
Henry Foster, R. N. F. R. S. 
Previous to leaving England in the spring of 1824, 1 had 
determined upon making a series of observations on the daily 
variation of the magnetic needle, during our stay, at the dif- 
ferent places which might be visited by the Expedition. 
Accordingly, soon after our arrival at the Whale Fish Islands, 
for the purpose of transhipping the stores from the Transport 
which had accompanied us thus far ; the instrument for ob- 
serving the diurnal variation was landed, and placed on a 
pedestal in a small octagonal observatory. 
The length of the needle was 11 inches, and weighed 120 
grains ; it rested on a pivot ; and its direction when the sun 
was on the magnetic meridian I assumed, for distinction’s 
sake, the zero of my scale. The observations were con- 
tinued for three days only ; and as the brass work of the in- 
strument was afterwards found to be magnetic, the results 
obtained are, of course, too doubtful to be considered of any 
great value taken singly ; but as it was these observations 
which first indicated to me the agency of the sun, in pro- 
ducing the interesting phenomenon of the daily variation, I 
have thought it right to give them in detail, together with 
such remarks as occurred to me at this early stage of the 
enquiry, as preliminary to the more extended and exact ob- 
servations made at Port Bowen by Captain Parry, the other 
Officers of the Expedition, and myself, an account of which 
accompanies this communication to the Royal Society. 
