minaret: a station reputedly so powerful that it could receive Berlin's
nightly outgivings of news and orders, and, in emergency, transmit them to
other secret stations in Cuba, Mexico, and Venezuela.

Yet the shrewdest scrutiny of eyes trained to detect police agents at
sight, however well disguised, failed to espy one sign of any sort of
espionage upon this nest of rattlesnakes.

Apparently its tenants came and went as they willed, untroubled by and
contemptuous of governmental surveillance.

A handsome limousine car pulled up at its carriage block as Lanyard drove
by, one time, and a pretty woman, exquisitely gowned, alighted and was
welcomed by hospitable front doors that opened before she could ring: a
woman Lanyard knew as one of the most daring, diabolically clever, and
unscrupulous creatures of the Wilhelmstrasse, one whose life would not have
been worth an hour's purchase had she ventured to show herself in Paris,
London, or Petrograd at any time since the outbreak of the war.

He drove on, deep in amaze.

Indications were not wanting, on the other hand, that enemy spies
maintained close watch upon the movements of those who frequented the house
on West End Avenue. A German agent whom Lanyard knew by sight was strolling
by as his taxi rounded its corner and swung on down toward Riverside Drive.

This more modest residence possessed a brick-walled garden at the back, on
the Ninety-fifth Street side. And if the top of the wall was crusted with
broken glass in a fashion truly British, it had a door, and the door a
lock. And Lanyard made a note thereon.