246 I. P. Kocn. 
dition, but they are so small that they are of no importance as to 
the problem before us. 
Consequently I see no other possibility than to seek the ex- 
planation in another direction than through errors in the observations, 
and, as far as I know, nothing is here forthcoming except the hypo- 
thesis put forth by Dr. WEGENER as regards the drift of Greenland 
towards the west. Dr. WEGENER estimates the period that has elapsed, 
since Greenland broke loose from Norway, at 50000 to 100000 years. 
The distance between Greenland and Norway he puts at 1400 kilo- 
metres, and in this manner he arrives at a average yearly drift of 
14— 28 metres, which computation rests on a supposition so uncertain 
that there is nothing to prevent the movement from falling even 
rather far outside the limits found through the estimate. 
If one takes it for granted that Greenland at 74°—77° latitude 
has really drifted 1190 metres towards west within the period 
1870—1907, the consequence is an average yearly drift within the 
period mentioned of 32 metres. The hypothesis of WEGENER thus 
receives a not inconsiderable support, but can of course not be 
looked upon as proved by this means. It will, therefore, be of great 
interest, if other criteria of the drift are found. 
In his oft-mentioned treatise WEGENER has made an attempt to 
provide such a criterion, by means of the determination of longitude 
of SABINE in 1823. In this manner he arrives at the result that the 
drift towards west within the period 1823—1870 should amount to 
260m. This computation rests on a very insecure foundation; but 
in case one wishes to carry it ihrough, the main source of the 
valuation of the site of SasınE’s Observatory must be the indication 
of the latter on the map drawn by CLAVERING in 1823. As WEGENER 
has not had access to this map, I will in this place take up the 
matter for renewed investigation. 
What makes the investigation uncertain is the fact that one does 
not know the site of the Observatory of SABINE, but is reduced to 
conjectures. 
On his map CLAVERING has marked off the meridian through the 
Observatory of SABINE, and on the map itself he has expressly given 
it as “Meridian of the Observatory 18°50'00” west of Greenwich”); 
but he has not in any other way indicated the site of the Observatory 
1) Chart of the East Coast of Greenland between the latitudes of 72° and 76° 
from observations on H. M. Ship Griper, Douglas CHARLES CLAVERING Esq. 
F.R.S., Commander, 1823. The map is published for the first time in copper- 
plate print in EDwArD SABINE's work: An account of experiments to determine 
the figure of the earth by means of the pendulum vibrating seconds in different 
latitudes. London, 1825. 
