Mystery floor safe

[Kiarek]

Hi everyone,

started rewiring my house today and had to go under the floor to get cables in, in the corner of one of the livings rooms I found a big "structure" it was about 2 foot of cement each side and a foot of bricks cemented into the cement, after breaking a hole in the floor of the room I found a small round safe lock, with a handle to pull what I presume to be a tube ? Once the lock is open. There was also a tag with strange writing on it, the houses current wiring is atleast 40 years old, so I'm guessing the safe is atleast that, I tried turning the lock and got no sound or clicks I don't know if that's normal, the only logo on the safe was on the turning "Seargent greenleaf " you will see in the pictures below.

Im presuming there's nothing in the safe and I wish not to use it however I would like to open it just once, just so I can say I did and because it's really interesting! , if anyone could help that would be
amazing !
Ryan