Popular Science Monthly 



549 



plainly enough. When even. the periscope 

 will betray her, which it does partly on 

 account of its wake, she must dive com- 

 pletely and become absolutely blind. 

 Hence, the periscope has been fittingly 

 called the "e^-e" of the submarine. It is a 

 telescope built so that you can see around 

 a corner or over a wall of earth or 



Photo 



Central 



News 



Above: What 

 one sees in look- 

 ing through the 

 periscope "eye" 

 of a United 

 States submarine 



The commander 

 of a submarine 

 looking through 

 a periscope at 

 the outside worid 

 from under-sea 



) Underwood and Underwood. N. T. 



water. There are as many kinds of per- 

 iscopes, almost, as there are styles in hats. 

 Each boat in all navies carries at least two 

 periscopes, one for the commanding officer 

 and one for the helmsman or second officer. 



The One-Man Submarine 



Henry Ford's proposal to build cheap 

 one-man submarines has once more focused 

 attention on an idea that has always fas- 

 cinated inventors. But no one who is at 

 all familiar with submarines believes in the 

 one-man type. In a letter to the Popular 

 Science Monthly, Simon Lake, our fore- 

 most submarine inventor, disposes of the 

 question in this fashion: 



"A number of one-man submarines have been 

 built, but they have never proven to be of much 

 value because they had such a short radius of action 

 and low speed. The modern Whitehead torpedo is 

 something over 1 8 feet in length and i8 inches in 

 diameter, and it requires a good sized vessel to carry 

 otie of these within the hull. If carried outside the 

 hull, which has been done in some cases, the torpedo 

 offers much additional resistance to a small craft and 

 thus tends further to reduce its speed. 



"We prepared a number of one-man boats, which 

 our engineers designate 'pickle-boats,' but they were 

 very disappointing as to the speed it was possible to 

 get out of them." 



This was not written of the Ford plan, 

 but on the subject in general. 



Ford's idea of building 

 one-man boats very 

 cheaply is ridiculed by 

 naval men. The engine 

 necessary to obtain high 

 speed would have to be 

 as light as an aeroplane 

 motor, and aeroplane 

 motors cost about $5,000 

 each. 



Thomas Orchard Lisle, 

 a prominent marine engi- 

 neer, punctures the Ford 

 idea very effectively when 

 he points out what are 

 its limitations: 



"Mr. Ford proposes to 

 drive this submarine with the 

 same engine that is used in 

 his automobiles, of which, I 

 believe the maximum horse- 

 power is forty under the best 

 conditions. This would give 

 a small boat, say twenty feet 

 long, a submerged speed of 

 not more than eight knots; 

 that is if an internal combus- 

 tion engine could run when 

 the boat is submerged. So 

 imagine the futility of chas- 

 ing a thirty-knot battle 

 cruiser with an eight-knot submarine." 



Mr. Ford has not considered among other 

 things, the difhculty of supplying air to the 

 engine and to the solitary constituent of the 

 crew, nor the disposal of the exhaust gases, 

 so that they may not betray the boat 

 in a soda-water wake, nor the utter impossi- 

 bility of operating such a boat in a rough 

 sea. 



In their mine-layers the Germans have 

 developed a new and ingenious type of sub- 

 marine. One of the mine-layers was cap- 

 tured by the British last year, and the 

 details of her construction have been given 

 out by her captors. She is about no feet 

 long, and 1 1 feet beam, and she displaces 



