30 REPORT OF THE SECRETARY. 



been lent to the Coast Survey, to be vibrated at New York, Wash- 

 ington, and Key "West. The observations at New York will afford 

 the means of connecting the results of a similar kind in Europe and 

 other parts of the Old World, through the series of observations made 

 by General Sabine in that city in 1822-23, at the old site of Colum- 

 bia College. 



The observations of part second, which relate to magnetism, are 

 of two kinds, namely, differential and absolute; the first made at Port 

 Foulke, between November and March, 1860-61, on fifteen days, 

 during each hour of the twenty-four, being intended' to ascertain the 

 diurnal variation of the magnetic needle. The results of these ob- 

 servations are presented in connexion with those of Dr. Kane, in 

 the form of a curve in which the agreement is strikingly exhibited. 



From both series it appears that the north end of the needle at- 

 tains its greatest westerly deviation atone p. m.; its greatest easterly 

 deflection, between two and three o'clock in the morning; its normal 

 position, at seven in the morning, and at the same hour in the evening. 

 From these additions to our knowledge of terrestrial magnetism we 

 have been enabled to state the fact that when simultaneous observa- 

 tions are made at different places, the motions of the needle are found 

 to be governed by the local time at each place. From this it has been 

 inferred that the cause of the daily motion of the needle is connected 

 with the diurnal motion of the sun. The one o'clock greatest western 

 excursion is common to all localities in the northern magnetic hemi- 

 sphere, and is the most constant feature of the daily motion of the 

 needle. 



The declination was determined at fourteen localities on the coast 

 of Greenland, between latitudes 72 and 80. These have been dis- 

 cussed in combination with the observations of Dr. Kane, and the 

 result is given on a magnetic chart of the vicinity of Smith's strait. 

 The horizontal component of the magnetic intensity was determined 

 at seven stations, and these, combined with those by Dr. Kane, are 

 also represented on the same chart. The inclination or dip was ob- 

 served at six localities, and were similarly combined with Kane's 

 determination, and likewise exhibited on the same chart. 



It is a remarkable fact that but three auroras of sufficient brilliancy 

 to attract the attention of the observers were seen at Port Foulke 

 during the winter of 1860-61, though many were noticed during the 

 same period in lower latitudes; and this fact is the more interesting 

 since the position above mentioned is very nearly the centre of the 

 auroral belt as marked out by Professor Loomis, and exhibited in the 



