All anything, but just have an interesting observation. Preserver water after some time exhibits certain properties. More precisely on the walls of a glass of water appears a lot of small gas bubbles. This suggests that if you omit the newly poured a glass, such as a cube with zero buoyancy, it is because the deposited it bubbles - will emerge as buoyancy force acting on this "cube" will increase. A gas released at the surface, well kept. If the cube, initially immersed in the water emerges, then this process can be organized continuously cyclical with the commission of useful work, as an example to connect to generator, etc. 

 Possibly create such a river creeks in the warm season these plants. Or do, for such purposes along the river special pools. 

 For me it is just a note, but I hope someone may be, make this a reality. 

 And finally - if you do not believe me, it's very simple - type in a glass of water ... 

 12/28/1910. 

 Makukhin Sergey. 

 Angarsk. 

 P.S. Material is protected.