"But, my dear sir, he could have met Julie elsewhere with far less danger of discovery. Besides," Miller hesitated, "let us give the devil his due.

Spencer was evidently very much attached to Kathleen. With her image before him, I do not believe he spared a thought for the French maid."

Whitney looked his disbelief. "In this instance, I cannot speak well of the dead," he said slowly. "I know too much of Spencer's past. He was not above courting the maid and the mistress at the same time."

"Well, at least Spencer was no fool; if he did court Julie, it was not done in this house." Miller tossed his cigar stub into the ash receiver.

"It might be that he used the maid to assist him in securing information about your inventions."

"You may be right." Whitney started from his chair. "And Julie, perhaps believing in his protestations of affection at first, awoke to his duplicity, and took the occasion of his spying to kill him."

"Yes, that's about my idea."

"But--but--" Whitney turned bewildered eyes on his companion. "What prompted Spencer to desire to steal my inventions?"

"That we have still to learn. That he did try, I am as convinced as if I had seen him." Miller picked up another cigar. "And, Mr. Whitney, permit me to call attention to one very essential fact...."

"Go on," urged Whitney.

"That what Spencer failed to accomplish, others may."

"Nonsense."

"It is very far from nonsense." Miller's earnestness impressed Whitney.

"I do not for one moment believe that Spencer was working alone."

"You hint at conspiracy?" Whitney frowned perplexedly.

"Call it that if you wish; only, sir, take every precaution to safeguard your inventions from prying eyes."

"I have, already."

"How, for instance?"

"With double locks, iron shutters, and electric wires, my workshop is hermetically sealed."

"Until a clever thief gains entrance." Miller laughed faintly. "The science of house-breaking keeps step with modern inventions to protect property. What one man can conceive another man can fathom."

"You may be right." Whitney took a short turn about the room, then stopped in front of his companion. "What precautions would you suggest?"

Miller did not answer immediately. "It is very likely that another attempt will be made to secure the drawings and specifications of your inventions, if not your models," he said finally. "And if on guard, you may not only catch the thief but Spencer's murderer."

"A good idea," acknowledged Whitney. "But how would you suggest going about to catch the thief?"

"By laying a plot for him; forget to lock your studio door occasionally, lay prepared paper inconspicuously about, and powder your tables and floor with fine dust. The thief will leave an indelible trail behind him."

"And walk off with all necessary data," answered Whitney skeptically. "As clever a thief as you paint will never leave that room, once he is inside it, without full knowledge of my inventions."

"The thief will not have an opportunity of stealing what he came for, because the specifications and drawings of your inventions will not be there."

"Eh!" Whitney's cigar fell unheeded to the floor. "Where will they be?"

"In my possession."

Too astounded to speak, Whitney stared at his companion. It was over a minute before he recovered himself.

"Do you think I will trust you with the drawings and models of my latest inventions?" he asked.

"You did not withhold your consent when, a short time ago, I asked for Kathleen's hand in marriage," said Miller slowly. "Do you hold your inventions dearer than your daughter's future happiness, which you are willing to intrust to my care?"

Never taking his eyes from his companion's face Whitney stepped back. The seconds lengthened into minutes before he spoke. "Come upstairs," he said and, turning, made for the closed door.

CHAPTER XIX

THE YELLOW STREAK

Leaving the War Department; Detective Mitchell debated for a second whether to walk around the back of the White House grounds to the Municipal Building, or to go to Pennsylvania Avenue and take an east bound electric car. But there was no sign of let-up in the pelting rain, and pulling his coat collar up about his ears, he hastened toward the avenue, and at sight of an approaching car broke into a run. The usually empty sidewalks were filled with hurrying government employees, anxious to get their luncheon and return in the prescribed half-hour to the State, War, and Navy Departments, and the detective had some difficulty in dodging the pedestrians.

Seeing an opening among the lowered umbrellas, he stepped off the curb and dashed for the street car. He was almost by its side when the hoarse sound of a motor siren smote his ear, and glancing sideways, he saw a touring car bearing down upon him at full speed. In trying to spring backward his foot slipped on the wet asphalt and he sprawled forward on his knees. The automobile was almost upon him when strong hands jerked him safely to one side. Scrambling to his feet, Mitchell turned to look at the man whose strength and quickness had saved him from a nasty accident.

"Much obliged, Captain Miller," he said. "I owe you a great deal."

Miller stooped over and picked up the detective's hat. "Why don't you chaps arrest such speeders?" he inquired, pointing to the vanishing car.

"We do in most cases," returned Mitchell, brushing the mud from his trousers, and limping back to the sidewalk. "However, the driver of that car is exempt."

"Why?"

"We can't arrest a United States Senator."

"Ah, then you got his number." Miller led the way to the sidewalk.

"That car doesn't need a number to identify it," grumbled Mitchell. "Its color and shape are too distinctive. We on the force call it the 'Yellow Streak.' The car belongs to Senator Randall Foster; when he's at the wheel, the Lord help the pedestrians!"

"So it would seem," dryly. "Where are you going, Mitchell?" observing the detective's rather shaken appearance.

"To the Municipal Building."

"Suppose you come and lunch with me first at the Occidental," and the smile which accompanied the invitation was very persuasive. "It's near where you are going."

Mitchell had not lunched, and a hurried breakfast had been consumed before six o'clock. It was his hunger which had occasioned his haste to reach the Municipal Building and later a near-by cafe. His official business was not very pressing, and since meeting Miller at the Whitneys' two days before, he had heard of his attentions to Kathleen Whitney. The rumor had interested him as much as Miller's personality.

Promptly he accepted Miller's invitation, and the two men boarded the next downtown car.

Within a short time they were both eating an appetizing lunch in the attractive restaurant of the Occidental. Just before the arrival of coffee and cheese, Mitchell sat back in his chair with a sigh of physical content. The Martini had warmed his chilled body, and the lassitude which comes after a hearty meal was stealing over him. Miller had proved an agreeable companion, able to talk upon any subject--except one, in spite of the detective's hints in its direction. Their table was in one corner apart from the others, and there was no danger of their conversation being overheard. Taking in their isolated position at a glance, the detective changed his tactics.

"I saw you at the Spencer inquest," he said abruptly, applying a match to his cigar. "What do you think of the verdict?"