That is odd -- the top looks like it is meant to seal something in an airtight environment, and then you get a screen that lets air in on the side. If the lid was not made of glass, I would wonder if it might be a small furnace of some kind. You would put charcoal in the bottom and force air through the screen area to super-heat the coals. You would insert a crucible at the top (filled with whatever you were trying to melt -- at that small size it would probably not get hot enough to melt anything harder than lead, pewter, aluminum or silver, possibly gold, but not silicon bronze or iron.) Then again, glass takes higher temps than all those, so it might have been a good way to peep in and see what was going on. That would actually be a handy set-up for melting metal for casting small objects like lead sinkers, toy soldiers and other small toy/ game pieces or jewelry, etc.) If the top was covered temporarily with refractory material, it would get really hot, really quickly! Of course, this all depends upon the metal casing of this thing. If it is made of steel or iron, no problem. Anything softer and you might melt the furnace along with the metal in the crucible. It may have been lined with refractory material at one time, but the crucible would be awfully tiny if the lining material was more than an inch or so in thickness. Just random thoughts.