I have some of those old steel gas cans people used to use with outboards. They're flat-bottomed, curved-topped, about 5 gallons and have the fittings to attach the outboard fuel line.

Does anybody have any idea how to determine whether they're sound without putting water in them? The only thing that occurs to me is to remove the cap and submerge them in a bathtub or garbage can full of water up to the neck of the fill port and see if air bubbles are generated. (Only the bad ones would get water in them.) Any other ideas?

Could  put the cap on , & apply slight air pressure through one of the fuel line fittings

Rubber stopper and fill them up with an air compresser.

Quoted: Any other ideas?

Well no, but can you send my your address again so I can mail Dr. Johnson's London back to you? Thanks

Quoted: Quoted: Any other ideas? Well no, but can you send my your address again so I can mail Dr. Johnson's London back to you? Thanks

IM sent. What'd you think of the book?