"Not a little bit," declared the girl. "Only take care of yourself."
"I'll try," rejoined the sub. "Don't make a sound. If—that is, supposing I don't come back, you had better make your way to Nedderburn and telephone to the senior officer of Auldhaig; but I fancy that there'll be no need for that."
Taking to the grass, Tressidar stole cautiously in the direction of the stationary car. His footsteps made no sound upon the springy turf. As he approached he bent low, taking advantage of the cover afforded by the numerous gorse bushes.
"So that's your little game," he mused. There were two men with the car. One, by the aid of the partly screened head-lamp, was consulting what was evidently a prismatic compass. The other, acting according to the movements of his companion's hand, was slowly shifting the car in its own length.
The mystery of the six red lights was now no longer a mystery. To the sub.'s keen intelligence the whole thing was as clear as daylight. The lid of the tool-box at the rear of the car had been partly raised until it formed an angle of 135 degrees with the back of the body. The lid, being of burnished metal, served as a reflector, so that the three red lights appeared to be six in a straight vertical line.
And that line pointed in the direction of the Sauchieblair Munition Works.
"That will do," said a voice in German—a language of which Tressidar had more than a general knowledge. "We're right on the exact bearing. Call up Pfeiller and inform him that our position is fixed."
The fellow who had been engaged in manoeuvring the car stepped inside the coupé. The faint cackle of a low-powered wireless apparatus was faintly borne to the sub.'s ear.
"Pfeiller reports all right at his position," announced the man after a brief interval.
"Let us hope he is sure on the point," remarked the German with the compass.