Sm. round metal and black glass(?) doohickey.

[BlackX]

Rang in nice but seems to mostly be made of black glass. Approx. 3/4" in diameter. Found in a ball field built in the early 1900s. Was farm fields earlier. Insulator of some sort?

 

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[mrs.oroblanco]

Looks like a boss.

B

 

[DaChief]

May be the bottom of a Pontil bottle. I have found many of those that looked just like that in older locations. Something similar to the Pontil bottom on these. Pontil bottles like this were made from three separate peices, the base being one of the three pieces. When you find a broken base, you get the domed effect which actually would have been the inside portion of the bottle base.

 

[mrs.oroblanco]

Couldn't find a black glass one, but.....

http://images.google.com/imgres?img...=glass+boss&start=288&ndsp=18&um=1&hl=en&sa=N

 

[QUICKSILVER (appletree)]

I'd say the bottom of an old light bulb or fuse

 

[Ammietuar]

Its the bottom edge of an old light bulb, ive seen quite a few of em when i was digging in old dumps. every now and then id find a whole one, but most were broken. i think the bottoms were made out of zinc and were usually seriously deteriorated. i got this one from googling "edison light bulb" http://i177.photobucket.com/albums/w210/anglelovr/No_Idea_by_imaginee.jpg