6 AKSEL S. STEEN. TERRESTRIAL MAGNETISM. [NORW. POL. EXP. 
a Fox apparatus! for the determination of inclination and intensity, accom- 
panied by a vibration-box with suspension-tube for observations of vibration. 
On the alhidade of the horizontal circle of the declinatorium, a_ horizontal 
brass rod is fixed on each side, for the application of the vibrating magnet 
as deflector. 
The apparatus is thus adapted for the observation of declination, hori- 
zontal intensity, inclination and total intensity. The horizontal circle is fur- 
nished with two verniers, which allow of direct reading to 0.5‘; increasing 
readings correspond to increasing easterly declination. 
As already mentioned, the constants of the apparatus were determined 
in Hamburg, before its despatch, by a series of observations taken between 
the 3rd and the 9th June, 1893, in the Compass observatory of the ‘Deutsche 
Seewarte’ by Dr. Neumayer and Captain Scort-Hansen together. Six months 
after the return of the expedition, between the 2nd and 7th March, 1897, a 
new set of constant-determinations was made by Captain Scorr-Hansen at 
the same place; but as electricity had been introduced on the neighbouring 
tram-line in the mean time, the value of the results of these observations is 
somewhat doubtful. For the sake of certainty, therefore, the instrument was 
taken to the Imperial Marine Observatory at Wilhelmshaven, where the 
observatory assistant, Herr E. Stick made a number of observations between 
the 17th and 20th April, 1897. These observations show that the constants 
of the apparatus were in the main unchanged from what they had been four 
years before. 
The thermometers belonging to the apparatus were tested during the 
expedition for the position of their zero, and occasionally also, for other 
temperatures, compared with the other verified thermometers of the expedition, 
some of which also were employed in the magnetic observations. All the 
temperatures quoted in this paper are given in centigrade degrees, and cor- 
rected for the error of the instrument; and they may be presumed to be 
correct to within 0°1° or 0:2° C. 
An ordinary anchor escapement watch by Haagensen was generally used 
in making the magnetic observations, and was constantly compared with the 
standard watch of the expedition, the Hohwii chronometer. In determining the 
time of oscillation of the magnetic needle, a Frodsham chronometer was 
' Handbuch der nautischen Instrumente. Zweite Auflage. Berlin, 1890, p. 275. 
