Under the Waves, Robert Michael Ballantyne [ebook reader macos .txt] 📗

bu'st him, if we were so disposed, if it wasn't for an escape-valve, here close beside the air-toobe, at the back of the helmet, which keeps lettin' off the surplus air. Moreover, there is another valve, here in front of the breast-plate, which is under the control of the diver, so that he can let air escape by givin' it a half-turn when the men at the pumps are givin' him too much, or he can keep it in when they're givin' him enough."

"An' what does he do," asked Rooney, with an anxious expression, "whin they give him too little?"

"He pulls on the air-pipe,--as I'll explain to you in good time--the proper signal for `more air.'"

"But what if he forgits, or misremimbers the signal?" asked the inquisitive recruit.

"Why then," replied Baldwin, "he suffocates, and we pull him up dead, an' give him decent burial. Keep yourself easy, my lad, an' you'll know all about it in good time. I'll soon give 'ee the chance to suffocate or bu'st yourself accordin' to taste."

"Come, cut it short and look alive," said Maxwell gruffly, as he stood up to permit of a stout rope being fastened to his waist.

"You shut up!" retorted Baldwin.

Having exchanged these little civilities the two divers moved to the side of the barge--Maxwell with a slow ponderous tread.

A short iron ladder dipped from the gunwale of the barge a few feet down into the sea. The diver stepped upon this, turning with his face inwards, descended knee-deep into the water, and then stopped. Baldwin handed him the blasting-charge. At the same moment one of the supernumeraries advanced with the front-glass or bull's-eye in his hand, and the men at the pumps gave a turn or two to see that all was working well.

"All right?" demanded the supernumerary.

"Right," responded Maxwell, in a voice which issued sepulchrally from the iron globe.

There are three round windows fitted with thick plate-glass in the helmets to which we refer. The front one is made to screw off and on, and the fixing of this is always the last operation in completing a diver's toilet.

"Pump away," said the man, holding the round glass in front of Maxwell's nose, and looking over his shoulder to see that the order was obeyed. The glass was screwed on, and the man finished off by gravely patting Maxwell in an affectionate manner on the head.

"Why does he pat him so?" asked Edgar, with a laugh at the apparent tenderness of the act.

"It's a tinder farewell, I suppose," murmured Rooney, "in case he niver comes up again."

"It is to let him know that he may now descend in safety," answered Baldwin. "The pump there is kep' goin' from a few moments before the front-glass is screwed on till the diver shows his head above water again--which he'll do in quarter of an hour or so, for it don't take long to lay a charge; but our ordinary spell under water, when work is steady, is about four hours--more or less--with perhaps a breath of ten minutes once or twice at the surface when they're working deep."

"But why a breath at the surface?" asked Edgar. "Isn't the air sent down fresh enough?"

"Quite fresh enough, Mister Edgar, but the pressure when we go deep--say ten or fifteen fathoms--is severe on a man if long continued, so that he needs a little relief now and then. Some need more and some less relief, accordin' to their strength. Maxwell has only gone down fifteen feet, so that he wouldn't need to come up at all durin' a spell of work. We're goin' to blast a big rock that has bin' troublesome to us at low water. The hole was driven in it last week. We moored a raft over it and kep' men at work with a long iron jumper that reached from the rock to the surface of the sea. It was finished last night, and now he's gone to fix the charge."

"But I don't understand about the pressure, sur, at all at all," said Machowl, with a complicated look of puzzlement; "sure whin I putt my hand in wather I don't feel no pressure whatsomediver."

"Of course not," responded Baldwin, "because you don't put it deep enough. You must know that our atmosphere presses on our bodies with a weight of about 20,000 pounds. Well, if you go thirty-two feet deep in the sea you get the pressure of exactly another atmosphere, which means that you've got to stand a pressure all over your body of 40,000 when you've got down as deep as thirty-two feet."

"But," objected Rooney, "I don't fed no pressure of the atmosphere on me body at all."

"That's because you're squeezed by the air inside of you, man, as well as by the atmosphere outside, which takes off the _feelin'_ of it, an', moreover, you're used to it. If the weight of our atmosphere was took off your outside and not took off your inside--your lungs an' the like,--you'd come to feel it pretty strong, for you'd swell like a balloon an' bu'st a'most, if not altogether."

Baldwin paused a moment and regarded the puzzled countenance of his pupil with an air of pity.

"Contrairywise," he continued, "if the air was all took out of your inside an' allowed to remain on your outside, you'd go squash together like a collapsed indyrubber ball. Well then, if that be so with one atmosphere, what must it be with a pressure equal to two, which you have when you go down to thirty-two feet deep in the sea? An' if you go down to twenty-five fathoms, or 150 feet, which is often done, what must the pressure be there?"

"Tightish, no doubt," said Rooney.

"True, lad," continued Joe. "Of course, to counteract this we must force more air down to you the deeper you go, so that the pressure inside of you may be a little more than the pressure outside, in order to force the foul air out of the dress through the escape-valve; and what between the one an' the other your sensations are peculiar, you may be sure.--But come, young man, don't be alarmed. We'll not send you down very deep at first. If some divers go down as deep as twenty-five fathoms, surely you'll not be frightened to try two and a half."

Whatever Rooney's feelings might have been, the judicious allusion to the possibility of his being frightened was sufficient to call forth the emphatic assertion that he was ready to go down two thousand fathoms if they had ropes long enough and weights heavy enough to sink him!

While the recruit is preparing for his subaqueous experiments, you and I, reader, will go see what Maxwell is about at the bottom of the sea.


CHAPTER TWO.


DESCRIBES A FIRST VISIT TO THE BOTTOM OF THE SEA.

When the diver received the encouraging pat on the head, as already related, he descended the ladder to its lowest round. Here, being a few feet below the surface, the buoyancy of the water relieved him of much of the oppression caused by the great weights with which he was loaded. He was in a semi-floating condition, hence the ladder, being no longer necessary, was made to terminate at that point. He let go his hold of it and sank gently to the bottom, regulating his pace by a rope which descended from the foot of the ladder to the mud, on which in a few seconds his leaden soles softly rested. A continuous stream of air-bubbles from the safety-valve behind the helmet indicated to those above that the pumps were doing their duty, and at the same time hid the diver entirely from their sight.

Meanwhile the two men who acted as signalman and assistant stood near the head of the ladder, the first holding the life-line, the assistant the coil of air-tubing. Their duty was to stand by and pay out or haul in tubing and line according as the diver's movements and necessities should require. They were to attend also to his signals--some of which were transmitted by the line and some by the air-tube. These signals vary among divers. With Baldwin and his party one pull on the _life-line_ meant "All right;" four pulls, "I'm coming up." One pull on the air-pipe signified "Sufficient air;" two pulls, "More air." (pump faster.) Four pulls was an alarm, and signified "Haul me up." The aspect of Rooney Machowl's face when endeavouring to understand Baldwin's explanation of these signals was a sight worth seeing!

But to return to our diver. On reaching the bottom, Maxwell took a coil of small line which hung on his left arm, and attached one end of it to a stone or sinker which kept taut the ladder-line by which he had descended. This was his clew to guide him back to the ladder. Not only is the light under water very dim--varying of course, according to depth, until total darkness ensues--but a diver's vision is much weakened by the muddy state of the water at river-mouths and in harbours, so that he is usually obliged to depend more on feeling than on sight. If he were to leave the foot of his ladder without the guiding-coil, it would be difficult if not impossible to find it again, and his only resource would be to signal "Haul me up," which would be undignified, to say the least of it! By means of this coil he can wander about at will--within the limits of his air-tube tether of course,--and be certain to find his way back to the ladder-foot in the darkest or muddiest water.

Having fastened the line, the diver walked in the direction of the rock on which he had to operate, dropping gradually the coils of the guiding-line as he proceeded. His progress was very slow, for water is a dense medium, and man's form is not well adapted for walking in it--as every bather knows who has attempted to walk when up to his neck in it. He soon found the object of his search, and went down on his knees beside the hole already driven into the rock. Even this process of going on his knees was not so simple as it sounds, for the men above were sending down more air than could escape by the valve behind the helmet, and thus were filling his dress to such an extent that he had a tendency to rise off the ground despite his weights. To counteract this he opened the valve in front, let out the superabundant air, got on his knees, and was soon busy at work inserting the charge-tube into the hole and tamping it well home, taking care that the fine wire with which it communicated with the party in the barge should not be injured.

While thus engaged he was watched, apparently with deep interest, by a small crab, a shrimp, and several little fish of various kinds, all of which we may add, seemed to have various degrees of curiosity. One particular little fish, named a goby, and celebrated for its wide-awake nature and impudence, actually came to the front-glass of the helmet and looked in. But the diver was too busy to pay attention to it. Nothing abashed, the goby went to each of the side-windows, but, receiving no encouragement, it made