Terry,
Page 60 of Cannons by Dean S. Thomas.
Thanks. I couldn't remember where I saw that photo.
Cannons is one of the books I have here, but I hadn't look at it in awhile.
An odd thing: In the bottom photo, the soldier is putting what looks like a linstock to the 'breech' of the log cannon, at a point where the bark appears to have been removed.
No mention is made of these log cannons being functional in any way.
Could it be that they were drilled out to make smoke and fire? On the one hand that would make them more convincing, but on the other hand I can't see the artillerymen wasting powder when ammunition was in such short supply.