Part 6 (2/2)

”What! with 164 miles of water behind it? Young sir, let me tell you that there'll be a clear depth of water of 80 feet all along this end of the lake we're forming. A body of water like that exerts terrific pressure, and to make that dam really secure against a fracture, to make an engineering job of it, as we should say, the dam ought to be constructed of masonry built right into solid rock. But there ain't no rock, more's the pity.”

”None?” asked Jim. ”Then you won't be able to use masonry?”

”Right, siree! But we're going to fix the business, and reckon, when the dam's finished, nothing'll move it. Listen here, and jest look away where I'm pointing. There's an army of n.i.g.g.e.rs and European spademen at work along the line the dam's to follow. They're working a trench right across, 40 feet down into the soil. Those engines you can see smoking along there are driving sheet piling of 4-inch timbers 40 feet down below the bottom of that trench. When they have finished the job of piling, the trench'll be filled chuck up with a puddled core of clay that'll act like a sheet anchor.”

”And so hold the dam in position,” suggested Jim.

”Just what I thought you'd say. No doubt that puddled core will help to hold the huge ma.s.s of earth that we're going to dump around it. But we're working that piling in and making the core for another purpose also. With a huge body of water in this hollow there'll be a certain amount of soaking into the subsoil--seepage we call it. It might loosen the ground underneath our dam, and so cause the thing to burst; but with a 40-foot trench, filled with a puddled core which'll stop any water, and this extra 40 feet of piling--just 80 feet of material altogether--we stop that seepage, and at the same time kind of fix a tooth into the ground that'll hold the weight of New York city.”

The whole thing was gigantic, or, rather, the scheme of it all; for the reader must realize that Jim and his friend were looking down upon an unfinished undertaking. But those smoking engines and the army of men at work were an indication of the enormous labour and skill required in the erection of this Gatun dam, itself only one item in the numerous works of the ca.n.a.l, though, to be sure, one of the vastest. In fact, When Jim learned that from base to summit the dam would measure no less than 135 feet, and would be 50 feet above the level of the water in Gatun Lake, there was no wonder that he gasped.

”It just makes a man scratch his head,” laughed Phineas. ”And sometimes it makes one inclined to swear, for there's folks in the States who can't cotton to what we're doing here, and who wonder why there are so many men employed and so much money being spent. They seem to think that the ca.n.a.l ought to be finished in a matter of three or four years.”

”Then the sooner they come out here and see for themselves what is happening the better for everyone,” cried Jim indignantly. ”That dam alone will take a vast amount of time, I imagine.”

”Then you come along down here, sir, and I'll show you a work that's just as gigantic.”

Phineas took our hero to the western end of the trench across which the dam would lie, and there caused him more astonishment. For here another army of labourers was employed in delving, while enormous steam diggers tore huge mouthfuls of earth and rock away from the sides of the cutting that was being made to accommodate the double line of three locks which, when America has completed her self-imposed undertaking, will raise the biggest vessel ever thought of to the surface of the lake above, or will drop her with equal facility down on to the bosom of the Atlantic.

”There's those steam navvies,” observed Phineas, halting in front of one and surveying it reflectively. ”A man who runs a machine like that can earn good dollars, and there's compet.i.tion for the post. Say, Jim, how'd you care to try your hand at it?”

The very suggestion caused our hero to hold his breath. It was not that he was frightened by the ma.s.s of machinery; it was merely the novelty of the work. He stepped a pace or two nearer before he answered, and watched closely what happened. A young American, only a few years older than himself, sat on a seat beside the gigantic main beam of the digger, his head within a few inches of the flying gear wheels which transmitted movement, while right beside him, fixed to the base of the steel-girded beam, was the engine. One hand was on the throttle, while the other operated a lever. Down came the huge bucket attached to the secondary beam, the chains which supported it clanking over their stout metal pulleys; then the hand operating the lever moved ever so little, the chains tautened, and the hardened-steel cutting lip of the digger bit into the bank which was being excavated. Deeper and deeper it went.

Glug! glug! glug! the machine grunted, while the tip of the main steel girder, where the hauling chains pa.s.sed over it, bent downwards ever so little. A shower of broken earth burst over the edge of the digger, a faint column of dust blew into the air, while the engine gave forth another discordant glug. Then up came the huge bucket, crammed to the very top with debris, the whole machine shuddering as the strain was suddenly taken off it. But the man remained as composed as ever. He touched another lever, causing the apparatus to swing round on its axis.

Almost instantly a movement from his other hand released the trigger holding the bottom of the huge earth receptacle in place, so that, before the machine had actually finished swinging, the huge mouth of this wonderful invention was disgorging its contents into a dirt car alongside.

”Fine!” cried Jim delightedly. ”That's a job I should like immensely, but I guess it requires a little training.”

”Practice, just practice,” smiled Phineas. ”See here, Jim; this arm of mine has started in aching again. How'd you care to stay along here and have a lesson? That young chap's a friend of mine, so there'll be no difficulty about the matter.”

It may be imagined that Jim eagerly accepted the offer. He was keen enough to accompany Phineas on his promised trip right along the ca.n.a.l works, but already the sight of all that was happening round about Gatun had been sufficient for one day, while the huge machine before him and its cool and unruffled operator fascinated him.

”Gee! nothing I'd like better,” he cried.

”Then come along.” Phineas at once went close up to the machine, and at a signal from him the operator brought it to a rest.

”Howdy?” asked the young fellow. ”Getting in at it, Mr. Barton?”

Under the tan which covered face and arms there was a sudden flush of pride which an ordinary individual might well have pa.s.sed unnoticed.

But Jim was slowly beginning to understand and realize something of the spirit that seemed to pervade every member of the whole staff engaged on the isthmus. For there was no doubt that the completion of the ca.n.a.l was a pet object to them one and all, an undertaking the gradual progress of which filled them with an all-absorbing interest. Each mouthful of dirt, for instance, which this steam digger tore from the ground and shot from its capacious maw into the earth trains was a little more progress, something further attained towards that grand and final completion to which all were sworn.

”Howdy? Say, Harry boy, this here's Jim. You've heard of that little business we had on the way to New York?”

The young man nodded, and regarded Jim critically. ”Wall?” he asked curtly.

”He's the lad that came along after me when I was left aboard the foundering vessel.”

The one who had been addressed as Harry dropped his hands from the levers, swung round on his seat the better to gaze at our hero, and, still with his eyes on Jim, replied to Phineas.

”I read it in the paper,” he admitted. ”How did it happen?”

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