THE NATIONAL GEOGRAPHIC MAGAZINE 



315 





ON THE FORWARD DECK OF A 



Photograph from U. S. Navy Department 

 DESTROYER 



The word "periscope" from the lookout brings instant action, and every man leaps to his 

 appointed place. Accuracy and eternal wakefulness are making the Atlantic sea lanes safer 

 and safer from the submarine peril. 



any other class in the country to apply the 

 rules and principles of this science, which 

 is rather neglected at present, when auto- 

 cratic nations regard a solemn treaty as 

 a mere scrap of paper. 



Navigation — a special branch of astro- 

 nomical science — is needed for every ship 

 that crosses the ocean, merchant as well 

 as naval. For accurate navigation, there 

 are required correct tables of the posi- 

 tions of the heavenly bodies at any time, 

 instruments for observing the sun, moon, 

 and stars, chronometers for determining 

 correct time, and compasses for deter- 

 mining directions. 



All work having to do with navigation 

 is centered, for the navy, at the Naval 

 Observatory in Washington, which com- 

 piles and publishes the Nautical Almznac, 

 universally used ; checks and corrects 

 chronometers ; studies compass problems 

 and naval instruments generally. All of 



this work is freely given to the public 

 and Utilized by mariners generally. 



The Hydrographic Office, another 

 branch of the Navy Department, estab- 

 lished more than fifty years ago by act 

 of Congress, has for its purpose, in the 

 words of the act, "the improvement of 

 the means for navigating safely the ves- 

 sels of the navy and mercantile marine 

 by providing . . . accurate and cheap 

 nautical charts, sailing directions, navi- 

 gators, and manuals of instruction . . . 

 for the benefit of navigators generally." 



THE WORK OF THE MEDICAL CORPS 



The principles of medical science apply 

 to men in the navy as well as others, and 

 the large and efficient Medical Corps of 

 the navy has always contributed its share 

 to the advancement of medical science 

 generally. In times of stress, such as 

 these, when the Medical Corps is much 

 more than doubled, it draws in medical 



