The eBay listing for this 1859 brass monstrosity says:
The Lens is almost 22″ long including the shade. The diameter of the front element is 6″. The diameter of the rear element is 7″. The Lens weighs 23 lbs and has a focal length of 22.5″.
And I thought the Schneider 360mm f/6.8 I just bought was comically large…