phs of persons who afterwards came to violent ends?"

"I begin to understand!"

"Thus far, his endeavours to concentrate the whole of the evil forces
at his command upon this house have had but poor results: having
merely caused Myra to dream strange dreams--clairvoyant dreams,
instructive dreams, more useful to us than to the enemy; and having
resulted in certain marks upon the outside of the house adjoining the
windows--windows which I have sealed in a particular manner. You
understand?"

"By means of photographs he--concentrates, in some way, malignant
forces upon certain points--"

"He focusses his will--yes! The man who can really control his will,
Rob, is supreme, below the Godhead. Ferrara can almost do this now.
Before he has become wholly proficient--"

"I understand, sir," snapped his son grimly.

"He is barely of age, boy," Dr. Cairn said, almost in a whisper. "In
another year, he would menace the world. Where are you going?"

He grasped his son's arm as Robert started for the door.

"That man yonder--"

"Diplomacy, Rob!--Guile against guile. Let the man do his work, which
he does in all innocence; _then_ follow him. Learn where his studio is
situated, and, from that point, proceed to learn--"

"The situation of Ferrara's hiding-place?" cried his son, excitedly.
"I understand! Of course; you are right, sir."

"I will leave the inquiry in your hands, Rob. Unfortunately other
duties call me."

CHAPTER XXIX

THE WIZARD'S DEN

Robert Cairn entered a photographer's shop in Baker Street.

"You recently arranged to do views of some houses in the West End for
a gentleman?" he said to the girl in charge.

"That is so," she replied, after a moment's hesitation. "We did
pictures of the house of some celebrated specialist--for a magazine
article they were intended. Do you wish us to do something similar?"

"Not at the moment," replied Robert Cairn, smiling slightly. "I merely
want the address of your client."

"I do not know that I can give you that," replied the girl doubtfully,
"but he will be here about eleven o'clock for proofs, if you wish to
see him."

"I wonder if I can confide in you," said Robert Cairn, looking the
girl frankly in the eyes.

She seemed rather confused.

"I hope there is nothing wrong," she murmured.

"You have nothing to fear," he replied, "but unfortunately there _is_
something wrong, which, however, I cannot explain. Will you promise me
not to tell your cl