Help what is it
Well it only took me 2days to figure out how to post this picture
On the gauge behind the needle it says CARB-O-TANK
Steel tank an porcelain outside

Maybe a acetylene generator ?

?

Dry ice container??

I would guess acetylene generator also. could also be a carbonator for a older soda dispenser?

Interesting unit.   Any ideas on the units and max on the gage?   How about that tube coming out the middle of the top?
It reminded me of a gas generator (a la http://www.rexophone.com/?p=1372 ).

Thanks for the replies some good ideas.Pick at auction.The guy was a tractor mechanic and had a repair shop at his place. On the underside of the lid there is a piece of copper tubing that that goes from the lid down to bottom of tank.

Maybe for Carbon tetrachloride or carbolic acid?

Some type of pressure tank.  Valve on the top is a schrader valve for air.  Should have a valve in it like an inner tube.  So you fill it and pressurize it then turn the valve to deliver what ever is in the can.

As to what went into it, I don't have a clue.  Looks like a moderate size opening on the faucet for some type of hose.

 time to take off the 4 wing  nuts and do a DNA test on the inside.

  just don't have your head too close if you open it.