THE CONQUEST OF THE ZONES 



not always easy to appreciate by the mere feel of the 

 line when the water is fairly deep. 



It is obvious that however well informed the navi- 

 gator may be as to his precise latitude and longitude, 

 he can feel no safety unless he is equally well informed 

 as to the depth of the water, the proximity of land, the 

 presence or absence of shallows in the region, and the 

 like. He must, therefore, as a matter of course, be 

 provided with maps and charts on which these things 

 are recorded. From the days when navigation first 

 became a science, unceasing efforts have been made to 

 provide such maps and charts for every known portion 

 of the globe. Geographical surveys, with the aid of 

 the method of triangulation, have been made along all 

 coasts, and elaborate series of soundings taken for a 

 long distance from the coast line, and there are now 

 few regions into which a ship ordinarily sails, or is 

 likely to be carried by accident, for which elaborate 

 charts, both of coast lines and of soundings, have not 

 been provided. The experienced navigator is able to 

 direct his ship with safety along coasts that he visits 

 for the first time, or to enter any important harbor on 

 the globe without requiring the services of a local pilot, 

 — albeit the desire to take no undue risk makes it usual 

 to accept such services. 



Time was, however, when maps and charts were not 

 to be had, and when in consequence the navigator who 

 started on his voyages of exploration was undertaking 

 a feat never free from hazard. Until the time of Mer- 

 cator there was not even uniformity of method among 

 map makers in the charting of regions that had been 



[43] 



