174 I. Р. Koch. 
The absurdity demonstrated is, however, practically independent of 
the value 0.160 in that the difference 0.160 — 0.138 — k* = (xx + = 
= + == Therefore there is every likelihood that the eight values 
of Jk used in the table p.173 are unfortunately placed for the 
comparison with the corresponding values of x and that the value 
= — 0.138 ought to have been greater ог un < 0.084. 
For the computation of x corresponding to the line of vision to 
the “Skerry” т and T are determined from observations of the 
temperature at the level of the sea and in the crow’s nest') made 
simultaneously or nearly simultaneously with the levellings. As the 
observations of temperature are made at a distance of about 85 m 
from land, and as the altitude of the crow’s nest is only 30 m, the 
values determined for 7 = (t,,—t,):30 and T = 273--1/2 (t,„+ t,) may 
be supposed to correspond fairly well with the conditions above the 
fjord, at an altitude of 15m. It will be borne in mind that the 
line of vision throughout its extent lies between the altitude 13.9 m 
and 16.4 m. 
There are in all nineteen levellings with simultaneous observa- 
tions of temperature. As far as the computation of the mean was 
concerned, it proved necessary to leave out the values of June 15th 
at 10P10. In the case of k it is, as in the case of Cairn X, the ab- 
normally high maximum value (k$ — 1.719) which is left out. 
The observations of temperature for the evening in question 
are as follows: 
8p 10p Midnight 
In the crow’s nest... + 3.0 + 2.1 + 1.4 
On the ice RE. — 1.0 — 0.4 — 2.6 
DAE speek ee ge NO Nee + 4.0 + 2.5 + 4.0 
И EL. + 0.133 + 0.083 + 0.133 
The levelling at the “Skerry” is made very nearly at 10P15, 
probably a little later than the observation of temperature given 
for 10Р. To the value К = 1.719 would correspond т = about 
+ 0.253 or ДЕ = about + 7.5 degrees — an uncommonly large 
inversion, which would however not have been obvious. Still the 
inversion in the harbour is measured at — 2.5, whereas at 8P and 
at midnight it is +4.0. In the journal of the levellings “strong 
glimmer” is recorded for the “Skerry” as well as a strong down- 
ward mirage, in other words conditions which seem to indicate 
disturbances in the conditions of refraction and great changes of 
1) See W. BRAND: Die Temperatur in der Ausguckstonne am Grossmast der "Dan- 
mark’; Medd. om Grønland, XLII. 
