524 Correspondence on Magnetism of Ships, [Nov. 30, 



over several years, was not only the improvement of the compass itself, but 

 the establishment of a system of compass-adjustment which has since been 

 uniformly followed in Her Majesty's Navy. ! 



" The principal features of this system are the following : 



" 1. The having in each ship a standard compass distinct from the steer- 

 ing-compass, fixed in a position selected, not for the convenience of the 

 helmsman, but for the moderate and uniform amount of the deviation at 

 and around it, by which compass alone the ship is navigated. 



" 2. The requiring each ship to be swung, and to be navigated by a Table 

 of Errors. 



" The Admiralty further at this period (1842), to ensure the proper 

 manufacture and adjustment of the standard compass, especially the selec- 

 tion of its position in the ship, and the general supervision of the ' swinging' 

 of the ships of the Fleet, created a small Compass Department, and 

 erected an Observatory and offices for the general examination of all the 

 compasses supplied to Her Majesty's ships. As a matter of opinion, I may 

 here express my belief that indirectly this latter establishment has tended 

 very much to the improvement of compasses generally. 



" The Admiralty at this time also issued a small book of Eules, known 

 as the * Practical Kules ' for ascertaining and applying the deviations of 

 the compass ; these Rules have undergone revision and addition from time 

 to time. (The latest edition is appended.) 



" General rules were also now laid down for guarding, in the equipment 

 of the ship, against the near proximity of iron to the compass : extracts 

 embracing the leading features of these Eules will be found in Appen- 

 dix 1. 



" In 1862, consequent on the increased use of iron in the construction 

 and armature of ships of war, there was issued for the service of the 

 Fleet, the ,' Admiralty Manual of the Deviations of the Compass,' a work 

 which, incorporating also the ' Practical Rules,' placed within the reach 

 of the educated seaman the theory and general principles of the magnet- 

 ism of ships, as also so much of the elements of terrestrial magnetism as 

 affected the navigator. 



" In the Mercantile Marine, regulations for the examination and adjust- 

 ment of the compasses are confined to sea-going passenger steamers. I 

 gather from the letter of the Board of Trade, in reply to the Royal Society, 

 as indeed I am aware from general personal knowledge, that practically, 

 except perhaps in the larger shipping companies, these regulations are 

 inoperative, or nearly so. 



" For example, there are no prescribed rules as to the number, the posi- 

 tion, or the efficiency of the compasses, and there is no guarantee for the 

 competency of the adjuster, in whose hands the whole arrangements are 

 generally placed. In many ports, and especially that of London, there is 

 inefficient provision for swinging the ships. 



** It appears unnecessary to remark, after what has just been briefly 



