Work of the U. S. Hydrographic Office 



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the positions of wrecks, derelicts, and 

 ice to their home offices as soon as they 

 are informed thereof by the Hydro- 

 graphic Office or by its branch offices 

 along our Atlantic seaboard. 



In order to still further aid navi- 

 gators by giving timely notice of new 

 dangers reported, it has been found 

 necessary to supplement the Pilot Charts 

 by the Hydrographic Bulletin, which is 

 issued weekly and gives the latest in- 

 formation of wrecks, derelicts, ice, and 

 other dangers to navigation. 



It has been found advisable, in fact 

 necessary, to have articles from time to 

 time on the Pilot Chart treating of some 

 essential for the navigator in the man- 

 agement of his vessel. Thus, during 

 each of the cyclone months in the North 

 Atlantic, an illustrated article is printed 

 either on the face of the chart or, if 

 there is not room there, on its back, 

 explaining the nature of cyclones, the 

 method of avoiding them, and, when 

 caught in them, proper directions for 

 managing a vessel. Articles on the use 

 of oil at sea, which have been the means 

 of saving valuable ships and of rescuing 

 the crews of wrecked vessels ; on the 

 use of instruments necessary in navi- 

 gation ; on the features which cause 

 disturbances of the compass, and on 

 various methods for obtaining the posi- 

 tions of vessels at sea and for plotting 

 the positions near a coast, are issued 

 whenever space and time permit. 



Until within the past year this Pilot 

 Chart was unique in being the only 

 thing of the kind published in the world; 

 but its importance to maritime interests 

 had been so thoroughly proved and the 

 necessity for immediate notice of all 

 dangers, particularly on frequently trav- 

 eled routes, had become so evident that 

 two other nations — England, the oldest 

 sea power, and German}', the young- 

 est — took up the matter and are now 

 issuing similar publications. 



I know of no government publica- 

 tion of more interest to those who go to 



sea than this, and feel sure that you 

 will agree with me after a short resume 

 of what it actually does for the mariner. 

 Let us consider the chart for the month 

 of February, 1903. 



In the upper left-hand corner of the 

 accompanying Pilot chart is a fog inset 

 chart, which is divided into i° squares, 

 each one of which contains a number 

 which indicates the percentage of days 

 of each month — i. e. , the number of days 

 in each one hundred — in which the 

 weather may reasonably be expected to 

 be foggy, these percentages being the 

 result of thousands of observations for 

 years back. They are only probabilities, 

 but they are good probabilities, and the 

 sailor makes use of them. But a short 

 time ago the captain of the flagship 

 Brooklyn told me that when conveying 

 the remains of the late Lord Pauncefote 

 to England last summer, the season of 

 maximum fog frequency, he followed 

 the fog forecast of the Pilot Chart for 

 the month and found it reliable. 



None but those in charge of vessels 

 can understand what a fog at sea means. 

 The sense is the nearest approach to that 

 of blindness that I can imagine. One 

 can see for some distance at night; but 

 in a thick fog such as what is known as 

 the blue fog of our northern waters — a 

 fog which is said by old salts to be as 

 thick as mud — the sense of sight fails 

 and that of hearing is brought into in- 

 tense play. But even the latter sense 

 fails under certain circumstances, such 

 as on a high-speed steamer, where the 

 noise of the engines and the swash of 

 the vessel's hull through the water shut 

 off all but unusually loud sounds. In 

 a late admiralty collision case — the 

 cutting down of a sailing vessel by a 

 steamer — the evidence showed that 

 while the people on the sailing vessel 

 had heard the steamer's whistle for 20 

 minutes before the collision, the officers 

 of the steamer had at no time heard the 

 fog-horn of the sailing vessel. 



The same of the sub-chart of gales, 



