78 SEVENTH REPORT—1837. 
high intensity with comparatively low dip; at King George’s 
Sound and Sydney, in 34° and 35° south latitude, Captain Fitz 
Roy found intensities of 1°71 and 1°68 with dips of 64° 41’ and 
62° 29’. 
Should such a separation exist at the secondary centres, it 
cannot be expected to be of so striking a character. I wish 
not to anticipate the more able discussion which we may ex- 
pect on this point from M. Hansteen, whose long and arduous 
journeys were undertaken expressly to determine with exact- 
ness all the phenomena of the Siberian pole. I will confine 
myself, therefore, to noticing his remark already referred to, 
that he believes the intensity observed at Viluisk to be the 
highest intensity existing in Siberia. Should this be so, the 
highest intensity in that quarter is certainly not in the same 
locality as the highest dip*. 
Our knowledge of the phenomena in the neighbourhood of 
the secondary centre in the southern hemisphere is not suffi- 
cient to throw any light on this question. 
With regard to the direction which the lines of higher 
intensity may be conceived to take around their maxima in 
the northern hemisphere, we should infer from the observations 
that the line representing 1°8 must be a closed curve around 
the North American maximum only; as must also be that of 1°9, 
supposing such to exist. 
The North American portion of the line of 1°7 appears also 
to be nearly, if not quite, a closed curve. Encompassed on the 
north, east, and south, by intensities of less value, the western 
is the only direction open for its connection with the Siberian 
portion of the same line. The situation of the two branches 
of the line of 1-7 in the west of America is marked by the ob- 
servations ;—the southernmost crossing the lower waters of the 
Columbia River,—and the northernmost between Sitka and 
Melville Island. Whether these branches join and form a 
closed curve, or whether they communicate with the Asiatic 
portion of the same line in some such courses as is represented 
by the dotted line in the polar map, observations do not yet 
enable us to decide. No intensity of so high a value as 1°7 has 
yet been observed between Sitka in 224°, and the meridian 
* It is much to be desired that the observations in Siberia should be still 
further completed by a series of determinations along the shores of the polar 
sea. If the view here taken be correct, these should exhibit higher dips and 
lower intensities than were observed at Viluisk. From the liberal support which 
the Russian government gives to the prosecution of magnetic inquiries we may 
expect that such observations will not be long wanting. 
