CHAP. XXL] PROTECTION OF BEACONS 503 



volved entirely militate against any such attempt being made. 

 All that has been attempted at present is to circulate as widely 

 as possible in general terms by a notice to mariners, etc., in- 

 formation relating to the presence of the shijjs and beacons, and 

 this especially to the fishery fleets, through H.M. Customs, 

 when working in home waters. 



When anchoring at night-, and desii'ous of protecting the 

 more exposed beacons situated near the general lines of traffic, 

 each vessel, as far as is prudent, can assist in this by selecting 

 a berth near them during fine weather, when no danger is 

 Ukely to ensue — occupying such a position that passing vessels 

 will, in keeping clear, naturally pass on the side of the ship 

 remote from the beacon, whilst the ship herself displays the 

 Hghts prescribed for a vessel engaged with telegraph cables. 



Dependent upon the cii'cumstances, it may frequently happen 

 that a beacon may be moored for a full month or more in one 

 position. 



Trawling vessels in the North Sea, when worldng independent 

 of fishery fleets, and desirous of maintaining a f)articular fishing 

 ground by night, generally attach a hand acetylene lamp to 

 the staff of a Dan buoy; this fight, which burns continuously 

 for upwards of thirty hom*s, is readily distinguishable at a 

 distance of 4 miles in clear weather. 



SECTION XXI. 



LIGHTVESSELS AND THEIR MOORINGS AND THEIR 

 USE IN TRIANGULATION. 



The mooring-chains of lightvessels, unless moored in re- 

 stricted positions, generally consist of a single chain of con- 

 siderable length — 150 to 200 fathoms' scope of cable is not 

 unusual in a dex)tli of 25 fathoms with exposed positions, 

 the nip in the hawse-pipe being by regulation constantly 

 altered. This should be borne in mind when conducting a 

 triangulation by the aid of lightvessels. Some arrangement 

 and understanding can, however, by the com-tesy of those 

 responsible on board, be made during the fine weather that we 

 shall depend upon whilst engaged upon triangulation. Sextant 

 angles are best obtained, especially at night, from a position 



