PRESIDENTIAL ADDRESS, B.A., 1871. 151 



Antarctic regions, and to plant on his way three 

 Magnetical and Meteorological Observatories, at 

 St. Helena, the Cape, and Van Diemen's Land. 

 A vast mass of precious observations, made chiefly 

 on board ship, were brought home from this expe- 

 dition. To deduce the desired results from them, 

 it was necessary to eliminate the disturbance pro- 

 duced by the ship's magnetism ; and Sabine asked 



\ 

 his friend Archibald Smith to work out from 



Poisson's mathematical theory, then the only avail- 

 able guide, the formulae required for the purpose. 

 This voluntary task Smith executed skilfully and 

 successfully. It was the beginning of a series of 

 labours carried on with most remarkable practical 

 tact, with thorough analytical skill, and with a rare 

 extreme of disinterestedness, in the intervals of an 

 arduous profession, for the purpose of perfecting 

 and simplifying the correction of the mariner's 

 compass a problem w r hich had become one of 

 vital importance for navigation, on account of the 

 introduction of iron ships. Edition after edition of 

 the Admiralty Compass Manual has been pro- 

 duced by the able superintendent of the Compass 



