Seeing Double (Check)

There are few tactics more powerful than double check.  Not only can it end a game abruptly, it's often hard to see it coming until some sacrifice reveals it lurking in the background.  In the game below John Schulten, a German-American master of the early-middle 19th century finds himself on the wrong side of a surprise sacrifice instigated by Bernard Horwitz, a noted chess problemist and member of the famous Berliner Pleiades.

Black to move: