164 ГР. Косн. 
уегзе4. In these cases I have given the zenith distance of the land 
and the Jz corresponding to it in brackets. 
Critical remarks on the observations. 
The observations had to be made incidentally, and they also 
bear indisputable witness to an unfortunate lack of systematic 
accomplishment. The chief lack is, I suppose, that there are no ob- 
servations whatsoever from the winter and the greater part of the 
spring. This was not to be avoided, partly because the darkness 
prevented us from seeing the cairns during the winter, and partly 
because in the period from March to June all our strength was re- 
quired for very far-going sledge-trips. The observations only cover 
the period from May 31st to October 21st, in other words, not quite 
five months, but on the other hand the observations within this 
period are so numerous, that in spite of their casual distribution 
they are able to give a fairly complete idea of the conditions of 
refraction. 
First and foremost it is obvious how extreme are the mean values 
of k determined by the Danmark-Ekspedition, as compared with the 
European determinations. In demonstration I am going to insert 
the determinations of the Danmark-Ekspedition in the series of 
various determinations of the co-efficient of refraction, given by 
ZACHARIAE !): 
Landesiriansulation; зови Чай... 0.1175 
о RUE N ee ee CRETE TER 0.1237 
Babyer, siehts in lan... NE NU ne ee 0.1239 
CATADOEUTELE > в Но 0.1285 
Landestriangulation, sights near the coast ................. 0.1292 
BASS RE. le ee ER 0.1306 
EPO dela Guerre Re... ONE ee MR Re 0.1350 
Baeyer; sights neartbegebast .......: SEER RR ans ee PTE 0.1362 
Ostpreussische \Gradmessumg :.2. оо san ann esse 0.1370 
Danmark-Ekspedition: sights across country .......... 0.160 
Бена те, 43 5.1: Bee... .... лоне Beate» ee 0.1678 
Baeyer siehts Aacrossaler...2... 2 nee En 0,1753 
Danmark-Ekspedition, sights across water ............ 0.516 
Danmark-Ekspedition,sightsacross watertotheseahorizon 0.584 
The oscillations to which the co-efficient of refraction is subject, 
are in the case of the Danmark-Ekspedition considerably greater than 
1) G. ZACHARIAE: De Geodætiske Hovedpunkter og deres Koordinater, Kjøbenhavn 
1876, p. 213. 
