Left to right
Bestone, copper with riveted backseam
American LaFrance, stainless
Acme, copper with riveted backseam
Allstate, brass
General, stainless, not soda acid type

All soda acid types still have glass acid jars with lead stoppers inside.

To charge one of these you would turn it over and acid would spill out of glass jar and react with soda contents.
This would cause a chemical reaction that would charge the can forcing contents out of tube. There was no turning these off once they charged and would spray until pressure ran out.