The situation offered suggestions of trouble that stung Tom to immediate action. The impetuousness of his giant often resulted in difficulties which the young inventor would have been glad to escape.

Now Koku was following just the wrong path. Tom Swift knew it.

"Koku, you madman!" he shouted after the huge native. "Come back here! Hear me? Back!"

Koku hesitated. He shot a wondering look over his shoulder, but his long legs continued to carry him down the slope after the dark-faced stranger.

"Come back, I say!" shouted Tom again. "Have I got to come after you? Koku! If you don't mind what you're told I'll send you back to your own country and you'll have to eat snakes and lizards, as you used to. Come here!"

Whether it was because of this threat of a change of diet, which Koku now abhorred, or the fact that he had really become somewhat disciplined and that he fairly worshiped Tom, the giant stopped. The man with the big shoes disappeared behind a hedge of low trees.

"Get back up here!" ejaculated Tom sternly. "I'll never take you away from the house with me again if you don't obey me."

"Master!" ejaculated the giant, slowly approaching. "That Big Feet--"

"I don't care if he made those footprints in the yard last night or not. I don't want him touched. I didn't even want him to know that we guessed he had been sneaking about the house. Understand?"

"Of a courseness," grumbled Koku. "Koku understand everything Master say."

"Well, you don't act as though you did. Next time when I want any help I may have to bring Rad with me."

"Oh, no, Master! Not that old man. He don't know how to help Master. Koku do just what Master say."

"Like fun you do," said Tom, still apparently very angry with the simple-minded giant. "Get back into the car and sit still, if you can, until we get to Mr. Damon's house." Then to himself he added: "I don't blame that fellow, whoever he is, for lighting out. I bet he's running yet!"

He knew that Koku would say nothing regarding the incident. The giant had wonderful powers of silence! He sometimes went days without speaking even to Rad. And that was one of the sources of irritation between the voluble colored man and the giant.

"'Tain't human," Rad often said, "for nobody to say nothin' as much as dat Koku does. Why, lawsy me! if he was tongue-tied an' speechless, an' a deaf an' dumb mute, he couldn't say nothin' more obstreperously dan he does--no sir! 'Tain't human."

So Tom had not to warn the giant not to chatter about meeting the stranger on the road to Waterfield. If that person with dried red mud on his boots was the spy who had followed Mr. Richard Bartholomew East and was engaged by Montagne Lewis to interfere with any attempt the president of the H. & P. A. might make to pull his railroad out of the financial quagmire into which it was rapidly sinking, Tom would have preferred to have the spy not suspect that he had been identified after his fiasco of the previous evening.

For if this Western looking fellow was Andy O'Malley, whose name had been mentioned by the railroad man, he was the person who had robbed Tom of his wallet and had afterward attempted reprisal upon the young inventor because the robbery had resulted in no gain to the robber.

Of course, the fellow had been unable to read Tom's shorthand notes of the agreement that he had discussed with Mr. Bartholomew. Just what the nature of that agreement was, would be a matter of interest to the spy's employer.

Having failed in this attempt to learn something which was not his business, the spy might make other and more serious attempts to learn the particulars of the agreement between the railroad president and the Swifts. Tom was sorry that the fellow had now been forewarned that his identity as the spy and footpad was known to Tom and his friends.

Koku had made a bad mess of it. But Tom determined to say nothing to his father regarding the discovery he had made. He did not want to worry Mr. Swift. He meant, however, to redouble precautions at the Swift Construction Company against any stranger getting past the stockade gates.

Arrived at Mr. Damon's home in Waterfield, Tom got quickly to work on the little job he had come to do for his old friend. Of course, Tom might have sent two of his mechanics from the works down here to electrify the barbed wire entanglements that Mr. Damon had erected around his chicken run. But the young inventor knew that his eccentric friend would not consider the job done right unless Tom attended to it personally.

"Bless my cracked corn and ground bone mixture!" ejaculated the chicken fancier. "We'll show these night-prowlers what's what, I guess. One of my neighbors was robbed last night. And I would have been if I hadn't set a watch while I drove over to see you, Tom. Bless my spurs and hackles! but these thieves are getting bold."

"We'll fix 'em," said Tom, cheerfully, while Koku brought the tools and wire to the hen run. "After we link up your supply of the current with this wire fence it will be an unhappy chicken burglar who interferes with it."

"That was an unhappy fellow who got your charge of ammonia last evening," whispered Mr. Damon. "Heard anything more of him?"

"I think I have seen him. But Koku spoiled everything by trying to eat him up," and Tom laughingly related what had occurred on the way from Shopton.

"Bless my boots!" said Mr. Damon. "You'd better see the police, Tom."

"What for?"

"Why, they ought to know about such a fellow lurking about Shopton. If he followed that Western railroad president here--"

"We'll hope that he will follow Mr. Bartholomew away again," chuckled Tom. "Mr. Bartholomew won't stay over today. When that chap finds he has gone he probably will consider that there is no use in his bothering me any further."

Whether Tom believed this statement or not, he was destined to realize his mistake within a very short time. At least, the fact that he was being spied upon and that the enemy meant him anything but good, seemed proved beyond a doubt that very week.

Having done the little job for Mr. Damon, Tom allowed no other outside matter to take up his attention. He shut himself into his private experimental workshop and laboratory at the works each day. He did not even come out for lunch, letting Rad bring him down some sandwiches and a thermos bottle of cool milk.

"The young boss is milling over something new," the men said, and grinned at each other. They were proud of Tom and faithful to his interests.

Time was when there had been traitors in the works; but unfaithful hands had been weeded out. There was not a man who drew a pay envelope from the Swift Construction Company who would not have done his best to save Tom and his father trouble. Such a thing as a strike, or labor troubles of any kind, was not thought of there.

So Tom knew that whatever he did, or whatever plans he drew, in his private room, he was safely guarded. Yet he always took a portfolio home with him at night, for after dinner he frequently continued his work of the day. Naturally during this first week he did not get far in any problem connected with the proposed electric locomotive. There were, however, rough drafts and certain schedules that had to do with the matter jotted down.

It was almost twelve at night. Tom had sat up in his own room after his father had retired, and after the household was still.

Eradicate was in bed and snoring under the roof, Tom knew. Just where Koku was, it would have been hard to tell. Although a fine and penetrating rain was falling, the giant might be roaming about the waste land surrounding the stockade of the works. The elements had no terrors for him.

Tom locked his portfolio and stepped into his bathroom to wash his hands before retiring. Before he snapped on the electric light over the basin he chanced to glance through the newly set windowpane which had replaced the one Rad had shattered in escaping threatened impalement on Koku's spear.

Although the clouds were thick and the rain was falling, there was a certain humid radiance upon the roof of the porch under the bathroom window. At least, the wet roof glistened so that any moving figure on or beyond it was visible,

"What's that?" muttered Tom, and he sank down lower than the sill and crept slowly to the window. He merely raised himself until his eyes were on a level with the sill.

Coming up over the edge of the porch roof was a bulky figure. It was so dimly outlined at first that Tom could scarcely be sure that it was that of a man.

However, it was not possible that any creature but a man would be able to mount the lattice supporting the honeysuckle vines and so creep out upon the porch roof. Once making secure his footing, the enemy in the dark approached directly the bathroom window at which Tom crouched.