At 09:28 AM 5/7/2002 -0800, you wrote: > Higher PPO2s can be tolerated in dry environments (chambers, habitats, etc.) since >there is no pressure gradient across the lungs as there is when in the water. Hi Sean, why is that a factor? Even vertical, wouldn't the gradient be very slight? Lung length, let's say 12"; 1/33' = .44 psi. William Alford walford@dbtech.net Tout comprendre c'est tout pardonner