Hollow glass tube with slider

[James57]

I found this today while detecting at a site where 3 1890s-1920s houses were demolished. I found some old relics and I came across this glass tube. It has a slider inside and I have no idea as to what it is. One side of the slider is flat with a crosshatch pattern on it. The other side of the slider has a peg that fits into the hole at the stubby end of the tube

Any ideas? Is it a valve of some kind?

 

Amazon Forum Fav 👍

Agony and Death on a Gold Rush Steamer: The Disastrous Sinking of the Side-Wheeler Yankee Blade - Grab it through Amazon!

[Monty]

bill gent, are you sure it's not a shrubbery? Your avatar is from my favorite classic movie. M nty

 

Amazon Forum Fav 👍

Upgraded Night Vision Monocular Digital Infrared Monocular Telescope for 100% Darkness with 8X Zoom - Grab it through Amazon!