Found in Brooklyn NYC

First thing I thought of was a button because of the holes on the back...

I googled D.W.S Brooklyn and came up with this site...

http://www.firehydrant.org/pictures/nyc3.html

Scroll a 1/3rd of way down... Its a shot in the dark but might be a button off of one of their uniforms.

looks like an early 19th century water line cap. These were in 2 pieces, flared a bit and marked by utility co. I am not an expert on this, but I did stay at a holiday inn express last night . But thats what it looks like to me

Well I have been doing some thinking on this also. Since its small and can be opened in half, to put something in, i belive its either one of two things.

In NYC there are a lot of water main breaks and leaks, i suspect that this was dropped in a nearby feeder line to rule out where the water was comming from. So in short put a dye marker in this thing and drop it into a nearby water supply line and a green dye was released, if you have green water in your basement or water running down your street then it's that line that the water was comming from.

Second, i think it could be a water mineral content tester, or just a tester in general. Because was i was shaking it and a heavy metal type substance was comming out of it. I still have them. Mabey they put a piece of lead in it to see how long it took to rot away. No Clue!

But i am done with it. LOL. I will be going to a Local NYC DEP office to ask some questions on it but im not going to go to crazy on this one thing.

Its my first old find and im sure it wont be my last.

:P