68 AKSEL S. STEEN. TERRESTRIAL MAGNETISM. [NORW. POL. EXP. 
observations, and after their termination. By the aid of this formula, I have 
drawn up a table of log y with ee expressed in scale divisions as argu- 
ment. The table contains the value of log y to 5 places of decimals, for 
every tenth of a ‘ 
The correction for rate of chronometer is calculated according to the 
usual formula: 
s 
e=1+ geno’ 
where s is the number of seconds gained or lost by the chronometer in 
24 hours. Log @ has been placed in a table with s as argument. 
The chronometer used as observation-chronometer on the 1st August, 
1893, was the Kutter; afterwards, until the end of 1894, the Haagensen 
watch was used, being compared before and after the series of observations 
with the Hohwii chronometer. It lost daily between 9 and 15 seconds. In 
1895 and 1896, the Frodsham chronometer was constantly used, being regu- 
lated according to sidereal time. Its daily acceleration in relation to mean 
solar time, which varied between 231°7 and 228'8 seconds, and its error on 
local time for the observation-days in question, have been given me_ by 
Professor GEELMUYDEN. 
As the time for the value of the horizontal intensity corresponding to 
each separate calculated time of vibration, I have taken the mean of the 
hour noted at the needle’s first and last passage over the middle division of 
the seale, reduced to local time. 
I have been unable to introduce any correction for the torsion force of 
the suspending thread, as no observations for its determination were made. 
After three series of vibration-observations with magnet VZ on August 
1st, 1893, at Khabarova, none were made until August 18th, 1894, when 
magnet V was used. After this the vibration time was determined regularly, 
most frequently for magnet V, now and then for magnet VZ. There are 
altogether 82 series of vibrations for magnet V, and 19 for magnet VJ. 
A few of the series, however, were made during such great disturbance, that 
the value of the time of vibration found must be considered very uncertain. 
