According to my copy of Ian Hogg's Twentieth-Century Artillery (Etobicoke, Ontario: Prospero Books, 2000), it's a 15cm Field Howitzer FH17. It was originally produced by Krupp for the German army in 1913, and quite a few survived the first world war to be used as training weapons during the second. Here are its specs:
From the information on the breech, this one appears to have been made in 1918:
A close up of the controls below. Really quite beautifully machined.
Finally, take a look at the end of the barrel. What could have done this?!
Being on the receiving end of such "whiz-bangs" was universally feared and deplored:
|Richard S. Lambert. The Twentieth Century Canada Britain USA. Toronto: The House of Grant (Canada) Ltd., 1960.|