CONQUEST OF TIME AND SPACE 



til the invention of rubber tires and the perfection 

 of the gasoline engine had made possible the type of 

 motor car that is making such universal appeal in 

 our own day. 



The case of the submarine boat is historically not 

 dissimilar. Invented in Revolutionary days, it met 

 with so cold a reception that almost a century elapsed 

 before it made another conspicious bid for favor. 

 Then, however, toward the close of the nineteenth 

 century, its cause was espoused with fervor, in partic- 

 ular by the American inventor, Mr. John P. Holland, 

 whose efforts are largely responsible for the develop- 

 ment of the submerged craft as a practical war- 

 machine. Another American, Mr. Simon Lake, has 

 perfected submarine craft adapted not only for 

 warlike uses, but also for the peaceful exploration of 

 shallow water, salvage operations, and the like. Mr. 

 Lake's submersibles are of "even-keel" type. 



As recently as the time of the Spanish-American 

 War, the authorities still looked askance at the anom- 

 alous vessel. But to-day submarines are as much 

 a part of the equipment of a modern navy as are 

 battleships. Submarines have been lowered to a 

 depth of more than two hundred feet, where the pres- 

 sure sustained was fifteen thousand tons. They have 

 been navigated for forty consecutive hours without 

 coming to the surface. Equipped with torpedoes 

 they are instruments of naval war that not even 

 the dreadnought can ignore ; and the newest types are 

 equipped with small cannon to operate at the surface, 

 though their role in this position must obviously be 

 subordinate. 



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