If you are so suspicious of every move I make, then go yourself and bring me what I want.

There is a map of Vienna pinned against the wall yonder.

Bring it to me." Jennie proceeded in the direction indicated.

It was an ordinary map of the city of Vienna, and as Jennie took it down she noticed that across the southern part of the city a semi-circular line in pencil had been drawn.

Examining it more closely, she saw that the stationary part of the compass had been placed on the spot where stood the building which contained the Professor's studio.