232 report— 1879. 



106,000 copies of Admiralty charts, and nearly 19,000 copies of the 

 Nautical Almanac, besides sailing directions and other books, are sold 

 annually to the general public and to foreign governments, exclusive of 

 the supply to the Royal Navy. Four hundred and fifty chart boxes, each 

 containing from 300 to 400 charts, are required for the Navy, and 1000 

 chronometers are in constant circulation between the Royal Observatory 

 and Her Majesty's ships. Foreign navies navigate by our charts, and all 

 our sailing directions are immediately translated, especially by the French 

 authorities. Another important function of the department is its respon- 

 sibility for all matters connected with the compasses of Her Majesty's 

 ships. 



The preparation of charts is under a superintendent, whose duties are 

 of a very important and responsible character. They are ably performed 

 by Commander Thomas A. Hull, who received his early education in the 

 school of Sir Francis Beaufort, and whose abilities as sailor, surveyor, 

 and draughtsman are well known. I have here a few Admiralty charts 

 selected to give a general idea of the different styles. They may be 

 divided into five classes : ocean charts, general charts of any particular 

 country or coast, coast charts, plans of harbours, and physical charts. 

 The latter have given a greater impetus to our knowledge of the causes 

 and effects of winds, currents, and temperatures than any publications that 

 have preceded them, and they have already been reproduced in France 

 and other countries. In the course of a voyage the sailor uses four 

 classes of charts. Fixing his position by astronomical observations, he 

 marks the ship's place and her track from day to day upon the ocean 

 chart, which is drawn on a very small scale. The curved lines on these 

 charts represent the lines of equal magnetic variation, and the small 

 figures show the deep-sea soundings ; these are of the greatest value to 

 our merchants, and to those interested in the laying of submarine cables. 

 They are also the result of great care and experience, as the ship must 

 be kept for hours in the same position to obtain them, telegraph engi- 

 neers requiring not only accurate position and depth of water, but also 

 samples of the bottom at great depths. They want to know what kind 

 of bed their cables are to lie upon. As the land is neared, larger scales 

 are required, and the next chart used is the general chart of the country 

 the vessel is bound to. When in sight of land, a coast sheet is prepared ; 

 and last of all comes the plan of the haven in which the weather-beaten 

 ship is to rest. 



When a coast has only been partially surveyed, the charts for it are 

 drawn in a light and unfinished style, which is a sufficient warning to 

 the initiated that the land must be approached with caution. As the great 

 aim of the Hydrographic Department is correctness, all charts are sub- 

 jected to the searching criticism of the naval assistants before publica- 

 tion, and it is to this measure that their extreme accuracy is to a great 

 extent due. The charts are not by any means done with when issued ; 

 they have then to be kept up to date. In fact, every chart published may 

 be regarded as a sort of official child, requiring the paternal vigilance of 

 the office to insure its doing good instead of evil. Correcting the charts 

 is a very delicate and responsible duty. All changes of lights, buoys, and 

 beacons have to be inserted, and as there are in round numbers 4000 

 lights and 10,000 buoys to be watched over, it is no trifling task. The 

 change of a single light or buoy sometimes necessitates the correction of 

 no less than five charts. These corrections, though small, must be made 



