NAVIGATION CURTISS. 133 



Equipped with the compass and log, sextant, chronometer, lead, 

 Nautical Almanac, and the Requisite Tables the navigator was ready 

 to sail with comparative safety over long voyages early in the nine- 

 teenth century. The crying need was for more and better charts and 

 for better knowledge of tides, winds, and currents. The establish- 

 ment of the Admiralty Hydrographic Office of Great Britain in 1795 

 marked a great step in advance in these directions. The first official 

 catalogue of the Admiralty, issued in 1830, listed 962 charts. And 

 in 1832 official tide tables were issued also by the Admiralty. At 

 present the navigator's charts cover all the important coasts and 

 seas, with very full data of tides, winds, and currents. 



In the United States, marine chart work began in the Navy De- 

 partment in 1837. From 1844 to 1861 the United States Observatory 

 and Hydrographic Office under Lieut. M. F. Maury devoted itself 

 not only to astronomical and hydrographic work but also to im- 

 portant research in marine meteorology. This period is notable for 

 the issuance of Maury's famous " Wind and Sailing Charts " and 

 " Sailing Directions." It was Maury's wish that the wind and sail- 

 ing charts should be an exclusively American contribution to world 

 navigation. In 1866 the hj'drographic and meteorological branches 

 were disconnected from the Naval Observatory and given to the 

 present Hydrographic Office, and in 1904 the work of marine meteor- 

 ology was transferred to the Weather Bureau. The United States 

 Hydrographic Office conducts marine surveys, collects information 

 for nautical publications, and prepares manuals, charts, sailing direc- 

 tions, and nautical tables for the use of navigators generally. In 

 a single year it prints about four hundred thousand charts and 

 many more pamphlets and bulletins. It sells about one hundred 

 thousand charts and books to navigators each year. The United 

 States Coast and Geodetic Survey, as part of its activities, prepares 

 and distributes tide tables and also charts and pilots of our coasts. 



In recent times the great development of modern ships in both 

 size and speed has increased enormously the demands on those who 

 command and navigate them and has led to careful study and im- 

 provement of methods in navigation. Simplified procedure, better 

 tables, and a higher standard of preparation of the navigator have 

 been realized. On the instrumental side the sextant and chronometer 

 have been carried toward perfection, the sounding machine much 

 improved, and the gyro-compass introduced. The original model 

 of one of the best modern types of magnetic compass was patented 

 by Lord Kelvin in 1876. The gyro-compass is used side by side 

 with the magnetic compass, but can not be said to have superseded 

 it. The rotary or patent log came into general use about 1886, but 

 was introduced in the form usually employed at present in 1878. It 



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