96 Г.Р. Koch. 
in the temperature are comparatively slow and slight, will not do in 
arctic regions. Already during the autumn of the first year our ex- 
perience, on various sledge trips, was that the watches stopped, when 
their temperature fell below — 25° (Centigrade). Consequently the 
watches at home had to be kept in the “Villa”, where they stood 
on the table in their cases, next to the standard watch. Here the 
temperature was during the day + 10° to + 15° (Centigrade), at night 
during the coldest season, as a rule a couple of degrees below zero; 
on one occasion the temperature round the watches was as low as 
— 9° (Centigrade). The Karrusel watches stood these changes fairly 
well, and they maintained a rate which was sufficiently even and 
correct in proportion to the accuracy which was desirable as regards 
knowing the exact time. (The accuracy of observation could, in the 
case of the determinations of time, under favourable conditions be 
carried as far as tenths of a second). 
In the course of the observations of the sun, an ordinarily good 
pocket watch was used, whereas at night a Karrusel watch 57203 
was used, which was regulated according to sidereal time, and thus 
every time had to be taken to the Observatory. However, compari- 
sons before and after the observations showed, already at a tempera- 
ture of — 10° (Centigrade), that the rate of the watch was subject to 
change, when exposed to the low temperature for a certain period, 
say for instance more than an hour. In order to remedy this defect 
57203 was placed in a glass bowl with a cut glass rim fitted with a 
cover which became airtight, when the rim was smeared with vaseline. 
The glass bowl was lined with felt. This arrangement was a great 
improvement, though it could not altogether protect the observation 
watch against the influence of cold. 
On October 28th 1907 at a temperature of — 18° (Centigrade) a 
determination for longitude by the moon was made; this observation 
fell into two periods, each lasting about an hour, with an interval 
of a few minutes. The comparisons taken before and after the ob- 
servation, as well as in the interval between the two periods, showed 
that the observation watch in the first period had kept its rate un- 
altered, whereas it had in the last period gained about half a second. 
This might be supplemented by a number of similar examples. 
As the air in the glass bowl often contained greater quantities 
of moisture than what corresponded to the saturated vapour of the 
surrounding temperature, it often happened that the inside of the 
glass cover became covered with rime, so that the reading of the 
watch was rendered rather difficult. This we could guard ourselves 
against by carrying the glass bowl containing the watch into the 
open air, some time before the observation, taking off the cover, 
