Clues please as to what they are
 

As per picture.

Hi Lynn, the one in the centre is a form of liquid container and definitely would have had some kind of lid. I would also think that the thread would have been quite course. Being green, it must have been military. Great find. The other things are "Book Ends" :)

mystery
 

Hi Lynn,
We use a very similar unit in the race car world for adjusting rear roll centre on the watts link.
It is mounted inverted and attaches to the diff housing.

Thanks Colin and Euan. Now that one part is identified (the Military??? bottle) These look a little "over the top" for a Watts linkage. I'd have gone for a more simple Panard rod rather than build these.
Maybe a more specific original military use of the expensive brass and mortice threaded "jacks" would help.
They are being advertised on 'Trade Me' with the advertiser knowing nothing about them.
They look a bit expensive for leveling the lecture room white board, but who knows when it comes to the military.