NO. 6.] INTRODUCTION. VOYAGE ALONG THE COAST OF SIBERIA. LVII 



The present volume contains all astronomical observations made at sea 

 between the departure from Vardo and the enclosure in the ice in 1893, but 

 their application to the determination of the position of new islands etc. 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 JOHANSEN started northwards 1895 March 14, turned 

 southwestwards April 8, and got the first glimpse of land on July 23. It 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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