“I can make a guess, but before we are satisfied I must come here again.  Take another look at that kite, Louis.  Are there a few yards of string hanging loose from it?”

“Yes, there are.”

“Rather thick string—­unusually thick for the purpose?”

“Yes, but how do you know?”

As they drove home again Carrados explained, and Mr. Carlyle sat aghast, saying incredulously:  “Good God, Max, is it possible?”

An hour later he was satisfied that it was possible.  In reply to his inquiry someone in his office telephoned him the information that “they” had left Paddington by the four-thirty for Weston.

It was more than a week after his introduction to Carrados that Lieutenant Hollyer had a summons to present himself at The Turrets again.  He found Mr. Carlyle already there and the two friends were awaiting his arrival.

“I stayed in all day after hearing from you this morning, Mr. Carrados,” he said, shaking hands.  “When I got your second message I was all ready to walk straight out of the house.  That’s how I did it in the time.  I hope everything is all right?”

“Excellent,” replied Carrados.  “You’d better have something before we start.  We probably have a long and perhaps an exciting night before us.”

“And certainly a wet one,” assented the lieutenant.  “It was thundering over Mulling way as I came along.”

“That is why you are here,” said his host.  “We are waiting for a certain message before we start, and in the meantime you may as well understand what we expect to happen.  As you saw, there is a thunderstorm coming on.  The Meteorological Office morning forecast predicted it for the whole of London if the conditions remained.  That is why I kept you in readiness.  Within an hour it is now inevitable that we shall experience a deluge.  Here and there damage will be done to trees and buildings; here and there a person will probably be struck and killed.”

“Yes.”

“It is Mr. Creake’s intention that his wife should be among the victims.”

“I don’t exactly follow,” said Hollyer, looking from one man to the other.  “I quite admit that Creake would be immensely relieved if such a thing did happen, but the chance is surely an absurdly remote one.”

“Yet unless we intervene it is precisely what a coroner’s jury will decide has happened.  Do you know whether your brother-in-law has any practical knowledge of electricity, Mr. Hollyer?”

“I cannot say.  He was so reserved, and we really knew so little of him—­”

“Yet in 1896 an Austin Creake contributed an article on ’Alternating Currents’ to the American Scientific World.  That would argue a fairly intimate acquaintanceship.”

“But do you mean that he is going to direct a flash of lightning?”

“Only into the minds of the doctor who conducts the post-mortem, and the coroner.  This storm, the opportunity for which he has been waiting for weeks, is merely the cloak to his act.  The weapon which he has planned to use—­scarcely less powerful than lightning but much more tractable—­is the high voltage current of electricity that flows along the tram wire at his gate.”