Popular Science Monthly 



579 



of battleships is maneuvered in cruising 

 and battle formations. The visitors 

 were shown how a night blocicade is 

 formed. One vessel lighted up a harbor 

 entrance with its searchlight, while the 

 others cruised around on circular block- 

 ade with all lights out or very closely 

 screened. 



Only recently, as if to demonstrate the 

 versatility of these little ships, one of the 

 eight was placed on a motor-truck and 

 with six nuxv men from the recruiting 

 office standing at different positions on 

 the deck, the motor-truck made its way 

 through New York city, stopping at 

 corners to give a man an opportunity to 

 address the large crowds which never 

 ceased to gather. 



The truck with its cargo and its 



Detecting Enemy Submarines from 

 a Ship's Look-Out 



THE present war has demonstrated 

 that effective measures can be 

 taken against a submarine attack by 

 maintaining an efficient look-out. The 

 great difficulty has been that with the 

 best of binoculars and telescopes the 

 movement of the ship constantly dis- 

 turbs the observation. 



To overcome this difficulty, John 

 Gardner, the inventor of the Gardner 

 submarine signaling system, has devised 

 a method b\' means of which the observer 

 seated with his telescope supported on 

 a stand can be certain that his finding 

 instruments will always be parallel to 

 the surface of the sea, regardless of 

 the rolling and tossing of the ship. 



Men concealed within the ship's intenor optrate iiand levers which move it about on 

 the floor in any formation desired. Each ship is equipped with a complete signaling 

 system and with running lights, searchlight and truckUghts for night practice 



crew carried on its unique method of 

 recruiting for two weeks. During that 

 time the number of recruits increased 

 noticeably. 



The ship mounted on the motor-truck 

 shown in the illustration is a model of the 

 Connecticut. It is twenty-six feet long 

 and five feet wide. The turrets are eight 

 feet above the deck, and were so high 

 that the truck could not get under the 

 elevated road structure without first 

 cropping off nearly a foot of its height. 



He achieves this end b\- mounting a 

 pedestal securely to the deck, and on 

 this a seat with a table to support the 

 telescope on a standard. By the opera- 

 tion of a gyroscope the seat and table 

 are maintained in a position parallel to 

 the sea surface. Furthermore, the 

 platform with seat and table is rotated 

 from left to right by the gyroscope, 

 so that the observer need only concern 

 himself with keeping a sharp look-out 

 over his field. 



