This is one of the heliostats from the US Naval expedition to view the transit of Venus. (If you haven't seen the website, it is great. Take a peek here. This will open a new window, and when you finish looking, close the window and my page will still be here.)
(I added the slow motion control and flat mirror). I have the original crate this came in, and it still has the USNO lettering on it.
The next two pictures are from the Transit of Venus.