Just Possibly Less Stuck?

So, Gordan (barometer specialist) told me to undo the screw at the bottom of the barometer. Which i have done (Friday evening). As a result the leather sack that it was holding up (inside that cylinder bit) would expand and thus enable the mercury to move in response to changes in air pressure. As you can possibly see, there is no sign of any sack, leather or otherwise descending below the cylinder. And so i had assumed that having been stuck for several decades, the leather would have seized up. And that may well still be the case. However this evening i could just get my little finger into the gap at the bottom of the cylinder and could feel the leather (which I couldn't before). We shall see! I will update you with any further exciting advancements!