.^ppEisrDTx: T. 



ASTRONOMICAL OBSERVATIONS, 1864-18G9. 



NOTES ON THE OBSERVATIONS. 



Hjill took with liiiii in 1SG4 two sextants, a box and a pocket chronometer, 

 several compasses, and a dip-circle; the last instrument and one of the sextants 

 being loaned to him from the United States Coast Survey. 



From the experience of his first exiiedition, and from some farther practice 

 in the use of instruments after his return to New York, he hoped that he woidd 

 succeed in making some observations of scientific value, as well as extend the 

 knowledge of Arctic geography. 



In considering the observations here given, due allowance will be generously 

 accorded for errors for which he was not fully responsible. His own frank state- 

 ments of the extremely defective condition of his instruments have been more 

 than once noted in the preceding pages. His sextants were soon out of order. 

 The silvering of their mirrors in the Arctic winter cracked off, and their screws 

 and joints loosened by the inequality of expansion. He did not consider the 

 work done, with even the Coast Survey pocket sextant, good work ; and often 

 ex])ressed the regret that no labor or ingenuity of his could remedy the defects 

 caused by the iniiuences of the Arctic exposures to whi^h all of his ai)pliances 

 were subjected. The dij)-circle was broken in 18G4. 



The chronometers showed themselves, at first, to be good time-keepers, but 

 the roughness unavoidable in handling and trans])orting them across the ice-floes 

 soon disturbed their rates ; and in the last year of the expedition they more than 

 once ceased to run. 



The compasses were doubtless good ; his perplexity in regard to their work 

 arose, perhaps, chiefly from changes in the direction and force of the magnetic 

 influences in regions subject to sudden and powerful fluctuations. After making 

 due allowance for the error of taking some of his observations in the vicinity of 



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