I see these and similar every now and then. Without being there in person for a 'hands on', this could be a hot water holding/or/pressure tank for a boiler system. Did/does the home have radiators? Typically nowadays you will see the newer tanks installed hanging from the floor joists above the boiler itself. Resembles an old vehicle gas tank. The tank style pictured was used approx. 70-100 years ago. Before that, they were these big monster cast iron units.
Dom... I believe "Electra-Weld" is only in welding supply related businesses now, but they were heavily involved in the building of welded pressure tanks, or should I say 'vessels' in the old days.
Yes, Bob probably see's a lot more of these than I do, being in the big city and all.