Objects of Observing Stations. 97 



tion of the magnetic needle on Lake Erie is about 4° west, while in 

 Hudson Strait, at Cape Chidley, it is 50° west, and at North Bluff 

 it is 52° west. The vessel is guided by her compass, it is true, 

 but not alone by the direction of the needle, but by the true 

 needle, which is ascertained by calculating the difference between 

 the variation and the true north. This variation, as I have 

 observed, is more or less, according to place of observation, east or 

 west, north or south. The inclination or dip of the magnetic needle 

 at Toronto is nearly 75°, while at North Bluff, on Hudson Strait, it 

 is 84°. 



The instruments to be used by Mr. Stupart for these observa- 

 tions are, the unifiler magnetometer for determining the absolute 

 declination ; the dip circle ; an inclinometer for differential observa- 

 tions ; a declinometer for the same purpose ; a bifiler for showing 

 the horizontal force ; the sextant and the chronometer. 



