ade. It seems as if a thrust is made at
some object in the water. After several minutes the man is seated, and
turns downstream. It appears that the boat is simply drifting. Fore-most
sentinel starts back, keeping nearly opposite. This compels the one
farther down to make a circle and hide among some bushes several rods
from shore. Coming back to the rear, he discreetly trails along at some
distance, keeping boat and other spy in view. Near the boathouse the
rower turns toward shore. Forward watcher stops a few rods upstream
until the boat is fastened, then follows down the bank. After a long
tramp our employe sees the forward man pass down those rickety cellar
stairs, and the other spy cross over narrow alley into a small shanty,
with window opposite that basement entrance.

"Upon report of these incidents reaching the office, double watches are
assigned to shadow both cellar and cabin occupants. It becomes evident
that the cabin tenant is simply spying upon conduct of the others.
Fearing that any decisive attempt to learn his 'lay' may work
unnecessary complications, he has not been molested.

"This same Thames programme and tableau were enacted each of the two
succeeding nights. On last afternoon, shortly before dusk, both men came
up the stairs. They walk along together for a while, when the elder
stops at a stall where loaves of bread are exhibited. One of our agency
men is just ahead, lounging along lazily, but intently listening. The
elder, who slightly limps, softly says:

"'Get back early, Paul!' then glances nervously ahead. In subdued
whisper comes the reply, 'Yes, father.'

"That evening former performance is repeated. This important clew was
reported at headquarters shortly before your call.

"It cannot be otherwise than that Pierre and Paul Lanier are in London,
occupying the basement room down those old stairs. Paul makes these
night trips up the Thames to scene of his crimes. His conduct stamps him
as the murderer of Alice Webster and Oswald Langdon."

Sir Donald holds his peace while shrewd guesses are made as to causes of
such suggestive actions.

Still referring to his memoranda, the chief continues:

"Paul is partially deranged. The bodies pitched over the steep bank, and
he imagines will escape. Knowing that Alice Webster had been rescued
from the lake, he fears she may rise from Thames depths. Pausing at
shrubbery along the shore and scrutinizing of projecting branches is
through knowledge