A little off the rebreather topic, but.....

Just got a neat box in the mail. It's a cryogenic (liquid air) SCUBA. Ought to be good for many hours and it's smaller than a rebreather (and less complex to use, as it's really just an open circuit system fed by the gaseous boil-off of liquid air). I'm planning on mixing my own "air" from LOX (liquid

oxygen) and liquid nitrogen. This was I can make nitrox in any percent desired. Liquid air turns richer in 02 as it boils off over time, as the temperature for boil-off is lower for 02 than nitrogen.

The genesis of the system is that in the 1960's Jim Woodberry, who was working for NASA, built a spin-of system from the system he was engineering for Apollo and this system was marketed by Jordan Klein as the "Mako" cryogenic diving system. It was reviewed in Skin Diver (I have the original articles). Just after that was announced, the Russians copied it almost exactly as the "Kryolung". They only built a few, and it's one of these that I managed to obtain.

Interestingly, Jim Woodberry was Diving Officer at the Florida Institute of Technology when I took my degree there. I remember talking to him about the cryogenic systems, ad he taught my hyperbaric physiology courses. Small world!