NO. 6.] INTRODUCTION. VOYAGE ALONG THE COAST OF SIBERIA. LVII 
The present volume contains all astronomical observations made at sea 
between the departure from Vardé and the enclosure in the ice in 1893, but 
their application to the determination of the position of new islands ete. will 
be given in another volume. 
The Sledge Expedition. 
After a preliminary trial in the last days of February and the first days 
of March Nansen and Jouansen started northwards 1895 March 14, turned 
southwestwards April 8, and got the first glimpse of land on July 23. I[t is 
a matter of course that the observations during this expedition, where the 
principal work of the travellers was very often a struggle for life, and where 
the instruments had to be handled in temperatures down to —40° C with no 
other source of heat than the observer’s own body, could not attain any high 
degree of accuracy. The instrumental equipment for astronomical observations 
were the small altazimuth, the pocket sextant, and the two small compasses 
mentioned before; a glass horizon for the sextant was only used once, the 
level having been found to be cracked later on. The altazimuth was mounted 
on three fixed brass plates with radial furrows on the upper side of its box, 
with the latter standing on the hard packed snow, which was found to give 
a sufficient stability. The observer had to lie on the ice. On comparing the 
readings of the vertical circle of the altazimuth during this expedition with 
those taken on board an apparent difference will be found; while Mr. Scott- 
Hansen always noted the degrees by the vernier to the left, Mr. Nansen used 
for the same purpose the vernier on the opposite side to the object glass. In 
this manner half the difference between the readings in the two positions of 
the instrument, the telescope being in both cases pointed to the same fixed 
object, will give the altitude. The horizontal point of the circle differed only 
some minutes from 90°. It should be mentioned that the lines ruled on glass, 
forming the cross wires in the focus, are rather broad, between 1’ and 2’; 
while this introduces no difficulty for the observation of stars which can 
easily be set between the borders of the line, the Sun’s limb must be set 
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