Remove balls here! In addition to the hellish heat that one would have experienced in this enclosed space, manipulating the tools needed to carry red-hot balls of iron without losing one's appendages would have been awkward indeed.

Also, what I can only imagine is the sun shining through the motion of the leaves in the wind outside caused there to appear to be motion in the furnace? Let's pretend it's HEAT that's causing that phenomenon! WHAT a great (accidental) phtographer I am!