A workout to get AIR?

How much do the people on the surface like you? Enough to hand pump the air down to you at work?

John Date diving company advertises their state of the art hand operated diving pump, ‘designed to meet the demands of the general diving trade. It is powerful, yet comparatively light and portable’ (at only 740 pounds). They consisted of 3 cylinders of bronze with leather plungers and a cast iron frame. The large guage indicated air pressure and depth of water. Conveniently they supplied 4 carrying handles on the box that folded down when the pump is stationary.

I personally would like to know the CFM of my tender before jumping in the water?