684 



Popular Science Monthly 



tanks and fed to the cylinders. Compressed 

 air has been experimented with more or 

 less successfully. But that does not seem 

 to be economical. Why not liquid air, or, 

 better still, liquid oxygen? Four-fifths of 

 the air that we breathe is composed of 

 nitrogen which serves the very useful pur- 

 pose of diluting the oxygen that we really 

 need and preventing us from literally burn- 

 ing up. Since an engine is an inanimate 

 piece of machinery which can be con- 

 structed to meet certain operating condi- 

 tions, there seems no reason why liquefied 

 oxygen could not 

 be used effective- 

 ly. And so, I 

 have designed the 

 machinery which 

 is disclosed in the 

 accompanying il- 

 lustrations and 

 which, I am sure, 

 will drive a sub- 

 marine under 

 Water at high 

 speed and for 

 long distances. 



An engine is 

 driven by heat, 

 converted into 

 mechanical en- 

 ergy. Liquid 

 oxygen is very 

 cold. When it 

 vaporizes and be- 

 comes a gas again 

 it absorbs heat, 

 or energy, from 

 theheatingagent, 

 which combines 



in this case sea water and other means. To 

 make the most of our liquid oxygen, then, 

 this stored energy ought to be used for 

 propelling the vessel. Hence, in the de- 

 sign which I here present, the gas given off 

 by the liquefied oxygen is fed to an expan- 

 sion engine, which is an engine very much 

 like a steam engine in principle, the differ- 

 ence being that a compressed gas is the 

 motive agent instead of steam. It is evi- 

 dent that after the oxygen has expended 

 its energy in driving the piston of that 

 expansion engine, it is just as fit to breathe 

 as it ever was before. In other words, it can 

 be fed to the internal combustion engines 

 of the submarine to be mixed with fuel 

 as if it had never been utilized in the ex- 

 pansion engine at all. This is what I 

 have done. The result is that the me- 



liguid oxygen in coil 



heated by used cooling water 



chanical energy stored up in the liquid 

 oxygen serves to supply additional power 

 for driving the vessel and the oxygen itself 

 to furnish the medium without which there 

 can be no combustion. The captions ap- 

 pearing beneath the illustrations describe 

 the actual invention in such detail that it 

 is unnecessary to dwell further upon its 

 construction here. 



I have said that the exhaust gases of an 

 engine when discharged into the water 

 appear as bubbles on the surface and not 

 only betray the presence of the craft but 

 indicate the exact 

 course. In order 

 to dispose of these 

 gases, I discharge 

 them through an 

 exhaust device of 

 special type. 

 They are sifted 

 through millions 

 of small holes. 

 After that they 

 strike the pro- 

 peller, by which 

 they are beaten 

 up with the sea 

 water. Since 

 these exhaust 

 gases are com- 

 posed chiefly of 

 steam and carbon 

 dioxide, they will 

 be entirely ab- 

 sorbed by the sea 

 water after hav- 

 ing been thus mi- 

 nutely sub- 

 divided. No be- 

 traying wake will be visible. 



Compressed air in strong, steel tanks, 

 could no doubt be used to drive the engines 

 of a submarine under water. Indeed, the 

 experiments which have been made with 

 what is known as the Neff system, described 

 some time ago in the pages of the Popular 

 Science Monthly, have been encouraging. 

 Officers of the navy have criticised the use 

 of compressed air because of the wake. My 

 objection to the system is chiefly to the 

 nitrogen contained in the compressed air. 

 Nitrogen is not easily absorbed by sea water ; 

 it resists combination with all elements. 

 The whole difficulty of avoiding a wake is 

 more easily solved, to my mind, by utilizing 

 pure liquid oxygen. Moreover, no matter 

 how highly air may be compressed in tanks, 

 a liquefied gas is even more compact. 



oxygen « 

 heated by Jea water 



Diluting the Oxygen with .Hot Exhaust Gases 



Before it can be fed to the explosion engine after having been 

 exhausted from the expansion engine, the oxygen must be 

 diluted; otherwise it would simply destroy the explosion engine. 

 Hence, the oxygen after it leaves the expansion engine passes 

 into a tank where it is mixed with a certain quantity of the 

 hot exhaust gases (dried carbon dioxide and steam) from the 

 explosion engine. That quantity is carefully measured by a 

 meter pump and forced through a pipe into the mixing tank 

 as here shown. A certain amount of fuel (oil or gasoline) is 

 forced through a carbureter and supplied to the mixing tank 



