Throughout all this Bill shone as an entertainer, a mental uplift that was really welcome, so spontaneous and keen were his talks and comments on people and things. Gus, though having little practice, held his own at tennis and golf; in swimming races and other impromptu sports he greatly excelled; and when a young fellow who bore the reputation of an all-round athlete came for the week-end from the city, Gus put on the gloves with him and punched the newcomer all over an imaginary ring on the lawn to the delight of Mr. Hooper, Grace and Skeets, as well as the admiring Bill.

Throughout all this, also, there was an element of ill feeling, an often open expression of antagonism toward the boys, which probably the other guests all tensed unpleasantly, but which the contented, jovial host and his impetuous and volatile daughter hardly recognized or thought of.

Thaddeus, the thin-faced, pale, stoop-shouldered, indolent, cigarette-smoking nephew, though often treated with slight courtesy, continually pushed himself to the front, compelling consideration apparently for the sole purpose of exerting a counter-influence upon the popularity of Bill and Gus, especially the latter. The youth even went so far at times as to attempt an interference in the power-plant work, declaring that it did not proceed rapidly enough and that certain methods were at fault, to all of which Mr. Hooper turned a deaf ear.

There was nothing else but open warfare between Grace and Thad, Skeets also echoing the daughter's hostility, while the nephew easily pretended to ignore it, or to regard the sharp words aimed at him as jokes. He treated Skeets with as much contempt as her jovial manner permitted, but now and then it could be seen that his pale eyes glared at Grace's back in a way that seemed almost murderous.

One day Gus and George, the colored man, were working at the far end of the curved dam breast, the stone work having risen to four feet in height. Bill was stooping to inspect the cement on the near end and the view of the hill was cut off. Presently voices came to him, mostly a sort of good-natured protest in monosyllables; then Thad's tones, low enough to keep Gus from hearing.

"I tell you, Uncle, they're putting it over on you. It ain't any of my business, but I hate to see you having your leg pulled."

"'Taint!" was the brief answer.

"Well, if you don't want to think so; but I know it. Look at this dam: not over two feet thick and expected to hold tons of water. Wait till a flood hits it. Will it go out like a stack of cards, or won't it? And they're not using enough cement; one-fourth only with the sand."

"Grouting, broken stones," growled Mr. Hooper.

"Not sufficient, as you'll see. And does anybody want to say that a two-inch pipe is going to run a water wheel with force enough to turn a generator that will drive thirty or forty lights? Bosh!"

"They ought to know."

"You think they do, but have you any proof of it? What they don't know would fill a libra--"

"How 'bout that there triang--what you call it? They knew that."

"Oh, just a draughtsman's smart trick; used to catch people. I'm talking about things that are practical. You'll see. I'll bet you these blamed fools are going to strike a snag one of these days, or they'll leave things so that there'll be a fall-down. But what need they care after they get their money?"

Bill heard footsteps retreating and dying away; Mr. Hooper went over to Gus and, with evident hesitation, asked:

"Do you reckon you're makin' the stone work thick enough? It does look most terrible weak."

"Sure, Mr. Hooper. Bill'll explain that to you. Professor Gray and he worked out the exact resistance and the pressure."

And then Bill limped over; he had left his crutch on the hillside, and he said, half laughing:

"This wall, Mr. Hooper, can't give way, even if it had the ocean behind it, unless the stone and cement were mashed and crumbled by pressure.

The only thing that could break it would be about two days' hammering with a sledge, or a big charge of blasting powder, and even that couldn't do a great deal of damage."

"All right, me lad; you ought to know an' I believe you."

Mr. Hooper's genial good humor returned to him immediately; it was evident that he was from time to time unpleasantly influenced by the soft and ready tongue of his nephew. The old gentleman turned toward home and disappeared; a short time afterward Thad came and stood near where Gus was working, but he said nothing, nor did Gus address him.

Then the slim youth also departed and hardly half an hour elapsed before down the hill came Grace and Skeets, the latter stumbling several times, nearly pitching headlong and yet most mirthful over her own near misfortune; but little Miss Hooper seemed unusually serious-minded. A lively exchange of jests and jolly banter commenced between Skeets and Gus, who could use his tongue if forced to; but presently Grace left her laughing chum and came over to where Bill had resumed his inspection.

"They can't hear us, can they?" she queried, glancing back at the others.

"Why, I expect not," Bill replied, surprised and mystified.

"If I say something to you, real confidentially, you won't give me away, will you? Honest, for sure?"

"Honest, I won't; cross my heart; wish I may die; snake's tongue; butcher knife b.l.o.o.d.y!"

"That ought to do, and anybody with any sense would believe you, anyway.

But, then, it will be a big temptation for you--"

"Resistance is my nickname; you may trust me."

"Well, then, in some way," said the girl, dropping her voice still lower, "you are going to find that this work here won't be--it won't go--not just as you expect it to; it--it won't be just plain sailing as it ought to be and would be if you were let alone. There are things,"

she put a forceful accent on the last word, "that will interfere--oh, sometimes dreadfully, maybe, and I felt that I must tell you, but--"

Bill, wondering, glanced up at her; she stood with her pretty face turned away, a troubled look in her bright eyes, the usually smiling lips compressed with determination. The boy's quick wits began to fathom the drift of her intention and the cause thereof; he must know more to determine her precise att.i.tude.

"I must believe that you mean this in real kindness and friendliness toward Gus and me."

"Of course I do; else I would not have told you a thing," Grace said, blushing a little.

"I think it must be something real and that you know. This thing, then, as you call it, is more likely a person--some person who is working against us. You mean that; don't you?"

"Please don't ask me too much. I think you're very quick and intelligent and that you'll find out and be on your guard."

"I think I understand. Naturally you must feel a certain loyalty toward a relation, or at least if not just that, toward one who has your father's good will. Gus and I surely appreciate your warning; you'll want me to tell him, of course."

"I don't know. Gus is not so cool-headed as you are; I was afraid he might--"

"Trust Gus. He and I work together in everything. And I do thank you, Grace, more than I can express. Well keep our eyes open."

CHAPTER XIV

FURTHER OPPOSITION

The dam was built, the flood gate in place, the pipe valve set for further extension of the line down the little valley; and as the pipe had all come cut and threaded, Bill and George were working with wrenches and white lead to get the sections tightly jointed against the pressure that would result. Gus, the carpenter, was laying out the framing of heavy timbers reinforced with long bolts and set in cement on which the Pelton wheel was to be mounted.

Several days were thus spent; the water was pouring over the spillway of the dam and it was with satisfaction that the boys found, after an inspection one quitting hour, that the wall, five feet high, was not leaking a drop.

That night Gus came over to Bill's home and the two went over the plans until late; then Gus chatted awhile on the steps, Bill standing in the doorway. Suddenly, from over toward the northeast, in the direction of the upper tract of the Hooper estate, there was a flash in the sky and a dull reverberation like a very distant or m.u.f.fled blast. Bill was talking and hardly noticed it, but Gus had been looking in that direction and, calling Bill's attention, wondered as to the cause of the odd occurrence.

In the morning, as the boys descended the hill, George, who was always on hand half an hour ahead of time, came up to meet them and was plainly excited.

"Mist' Bill an' Gus, de dam's done busted a'ready an' de water's jes'

a-pourin' through t' beat ol' Noah's flood! Whut you 'low was de because o' dis givin' way?"

"By cracky, Bill!" was Gus' comment as they stood looking at the break which seemed to involve a yard square of the base and cracks, as though from a shock. "You know and I know that the water didn't push this out.

How about that flash and bang we heard last night?"

"I can't see how the water could have done it," said Bill, who evidently had more talent for construction than for determining destruction.