I think it is an Elephant head coat hook. The "hole" is where I bet decorative tusks were mounted. the smaller hole looks like an eye hole. Some similar but older than these. Or maybe a curtain rod end.
Re: I know it's a whistle, but????
Ya'll ain't never seen a cricket caller? We use 'em all the time on the river bank. You keep givin' it a toot every lil' bit and the crickets will sort of follow the noise. Makes it easier to find 'em. That way you have fish bait all day and night that you...
Re: some type of tool?
and its two different colors cuz after its erection was delayed by the civil war, they had to get "white" marble from a different location, first Maryland and then Massachusetts...
Here's my guess...
The end nearest the round neck seems to taper outward, perhaps this is for mechanical advantage...the end is circular, and I think we are focusing on the cavity containing something of value...so...I think it is...
A cigar punch? maybe?
or something used to punch a single...
I like to fancy myself handy around mechanical stuff, but I am certain, there are things that operate solely on the premise of black magic, and sewing machines are one of those things. I can operate, and even setup a sewing machine. I understand where the parts are, and what their jobs are, but...
the hammer seems to line up like a rim fire. doesn't look like a revolver. Almost looks like the item on the side would hold the bullet in place by spring action..like a reverse extractor.
.17HMR is smaller, but obviously not available when this gun was made, I imagine that's what you meant...