Under the Waves | Page 6

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,