152 POPULAR LECTURES AND ADDRESSES. 



Department, Captain Evans, containing chapters 

 of mathematical investigation and formulae by 

 Smith, on which depend wholly the practical 

 analysis of compass-observations, and rules for the 

 safe use of the compass in navigation. I firmly 

 believe that it is to the thoroughly scientific method 

 thus adopted by the Admiralty, that no iron ship 

 of Her Majesty's Navy has ever been lost through 

 errors of the compass. The BritisJi Admiralty 

 Compass Manual is adopted as a guide by all the 

 navies of the world. It has been translated into 

 Russian, German, and Portuguese ; and it is at 

 present being translated into French. The British 

 Association may be gratified to know that the 

 possibility of navigating ironclad war-ships with 

 safety depends on application of scientific prin- 

 ciples given to the world by three mathematicians, 

 I'oisson, Airy, and Archibald Smith. 



Returning to the science of terrestrial magnetism 

 \ve find in the Reports of early years of the British 

 Association ample evidence of its diligent cultiva- 

 tion. Many of the chief scientific men of the day 

 from England, Scotland, and Ireland found a 



