TERRESTRIAL MAGNETISM. 



The magnetic records were placed in the bands of the United States Coast and Geodetic 

 Survey lor computation and discussion. 

 The following report is presented: 



ACCOUNT AND RECORD OF THE MAGNETIC OBSERVATIONS WITH PARTIAL RESULTS 

 DEDUCED BY C. A. SCHOTT, ASSISTANT, COAST AND GEODETIC SURVEY. 



COMPUTING- DIVISION, COAST AND GEODETIC SURVEY OFFICE, 



May 6, 1884. 

 J. E. HILGARD, 



Hiiprrlntendent Coast and Geodetic Survey: 



DEAR SIR: Towards the end of March, 1881, Mr. Carlile P. Patterson, then Superintendent of 

 tLe United States Coast and Geodetic Survey, was invited to aid and co-operate in the researches 

 proposed by the International Polar Commission, which held its second session at Bern, Switzer- 

 land, in August, 1880, H. Wild, president. General W. B. Hazen, Chief of the United States Sig- 

 nal Corps. United States Army, having notified the Commission that the United States would take 

 part in the undertaking, caused two expeditions to be fitted out, one to proceed to Point Barrow, 

 Ah. ska. the other to Lady Franklin Bay, Gvinnell Land. The Coast and Geodetic Survey was to 

 co-operate in the magnetic work which these parties were to execute by furnishing such magnetic 

 and other instruments as were then available and by instructing three or four observers of the 

 Signal Corps in their use; besides bearing a part of the expense of the first-named expedition, the 

 second expedition having been provided for by special appropriation of Congress. 



PART I. INTRODUCTION. 



It was not until near the close of April that these preliminary arrangements were concluded; 

 and it was well understood, in consequence of the want of suitable magnetic instruments, and in par- 

 ticular of differential instruments, and owing to the fact that no trained scientific, observers \vereat 

 the lime available, that the Coast and Geodetic Survey could not then follow the minute instruc- 

 tions which had been prepared for the guidance of the various expeditions \vliieli were to take part 

 in the work of the Commission. In the words' of the Superintendent, we were simply to do for ter- 

 restrial magnetism the best that was possible at the time. For the, first year at Point I5arr;iw, and 

 during the entire absence of the other expedition, the assistance of the survey was more incidental 

 than fully co-operative; but this condition was considerably improved in the second year a; Point 

 Barrow, when we were able to send a set of differential instruments with a newly instructed observer. 

 In the summer of 1883 a special observer was sent in charge of pendulum work and particularly to 

 verify the magnetic work, as well as to redeterrnine the geographical position and the true, meri- 

 dian or a/.imutu: hut unfortunately he was unable to accomplish anything in consequence of the 

 continued rain, fog, or cloudiness of the sky during the few days he could stay at the place, the 

 state of the ice and the damaged condition of the vessel demanding a speedy embarkation of the 

 whole party. 



That under these circumstances the magnetic work should fall somewhat short of the accuracy 

 \vbuih the committee had desired it should possess is not surprising; indeed, the Polar Conference 



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