Marble in a bottle

I bought this at the vintage shop in Hebden Bridge, yesterday. I've never seen a bottle like it, with a marble built into its neck. Does anyone know what it's for?

I took this photo just after I'd finished packing and was about to catch the train from Oxenholme to Waterloo, as I'm spending the week in London. Once I'd schlepped across town with two bags, a satchel, and a suit bag, I checked into the hotel - opposite Waterloo East - and then went out to Roupell Street with my brother. There's a nice little pub there where we spent a couple of very happy hours :-)