2 Metaphors for acrobat

The shaky old gentleman, who played in the days when it was decidedly less dangerous to stand up to bowling than to a cannon-ball, and who now hobbles about on rheumatic joints, by the help of a stick; the corpulent elder, who rowed when boats had gangways down their middle, and did not require as delicate a balance as an acrobat's at the top of a living pyramidthese are the persons whom I cannot see without an occasional sigh.

But acrobats and danseuses had been alike brilliant, wicked impossibilities to my youth, for I had been reared a Covenanter of the Covenanters.

2 Metaphors for  acrobat