SUBMAEINE SIGNALING— THE PROTECTION OF SHIP- 

 PING BY A WALL OF SOUND AND OTHER USES OF 

 THE SUBMARINE TELEGRAPH OSCILLATOR.^ 



By R. F. Blake. 



Compared with other forms of transportation, the amount of 

 energy necessary to transport water-borne freight is very small, 

 and its cost Avonld be cheap indeed if it were not for the dangers of 

 the sea. We have fogs and rocky coasts, shoals and icebergs, cur- 

 rents and storms to guard against, and these add immensely to the 

 expense. Of this we have had a very recent instance, for, as the 

 result of the loss of the Titanic^ vessels carrying passengers are now 

 constructed with a complete double bottom extending above the 

 water line; in other words, instead of a single ship we must now 

 have two complete ships, one entirely inclosed by the other. And 

 the loss of the Empress of Ireland indicates that even this may not 

 be adequate. 



Bit by bit the dangers which beset the early navigators have 

 been overcome. The chart told him the best course to take from 

 one point to another. The mariner's compass enabled him to main- 

 tain his course when the stars were blotted out by clouds. With 

 sextant and chronometer he located his position, with log and 

 soundings he guarded himself when a sight could not be obtained. 

 More recently wireless telegraphy has enabled him to call 'assistance 

 in time of danger. But with all this, many dangers remain. The 

 more important of these are due to fog. 



The North Sea, the English Channel, and the Grand Banks, the 

 New England coast, the western coast of the United States, British 

 Columbia, and Alaska, and other points are all of them subject to 

 fogs, sometimes lasting for weeks at a time, and it is therefore not 

 surprising that thousands of lives are still lost at sea each year. 



And there is not only loss of life; the pecuniary loss is also very 

 great. It is no unusual occurrence for a score of steamers to be tied 

 up at one time, unable to enter harbor on account of fog or of the 

 combination of fog and rough weather. 



1 Reprinted by permission from the Proceedings of the American Institute of Electrical 

 Engineers, October, 1914. 



203 



