Secret Gasoline Supplies for Submarines
![image of submarine](http://upload.wikimedia.org/wikipedia/commons/thumb/9/93/PSM_V88_D067_Submerged_fuel_supply_for_submarines.png/1000px-PSM_V88_D067_Submerged_fuel_supply_for_submarines.png)
A submarine at sea can replenish its supply of gasoline or oil by means of the device illustrated. Within an outer container, a tank of gasoline or oil is placed. Between the outer container and the gasoline tank is a space filled with water. When the water is forced out by compressed air, container and tank rise to the surface
![image of a float hidden in seaweed](http://upload.wikimedia.org/wikipedia/commons/thumb/2/2e/PSM_V88_D067_Submerged_fuel_supply_raised_to_refuel_submarine.png/1000px-PSM_V88_D067_Submerged_fuel_supply_raised_to_refuel_submarine.png)
A float hidden in seaweed conceals the means of raising the tank to the surface. After the tank has been brought to the surface the submarine proceeds to replenish its supply of fuel by the simple expedient of pumping it into its reservoirs
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