it to have a very 

 shoald barre before 

 it ;" and, again, "the 

 mouth of that land 

 hath many shoalds." 

 Boats were repeatedly 

 sent ahead to sound 

 as the Halfmoon 

 worked her way into 

 the harbor and river. 



The natural altera- 

 tions in channels and 

 coast lines, the prog- 

 ress of improvements, 

 and the changes in the 

 trend and character of 

 commerce and ship- 

 ping make numerous 

 modifications neces- 

 sary in the aids to 

 navigation, so that this 

 Is a work that Avill 

 never be complete 

 while nature and man 

 are active. During the 

 past year notices have 

 been published of 

 about 1, 600 distinct 

 changes in aids to 

 navigation maintained 

 by the United States 

 Lighthouse Service. 



Among the light- 

 houses of the country 

 may be found ex- 

 amples of great engi- 

 neering skill and of 

 dignified and simple 

 design. Some of the 

 tall lighthouse struc- 

 tures are of beautiful 

 architecture, suited to 

 the purpose, and set 

 off by picturesque lo- 

 cation on headland or 

 rock overlooking the 

 sea. The tower must 

 be built to give the 

 light a suitable height 

 above the water, and 

 hence tall lighthouses 

 are required on low- 

 lying coasts. 



A light must be 

 about 200 feet above 

 the water to be seen 

 from the deck of a 



16 



