slanting,
and one could fancy the whole thing beautifully grown over with vines,
a graceful arbor-way suspended in mid-air. And down the length of
this came the strangest sounds--one would say a company of woodpeckers
of some giant sort making riot in an echoing forest.
_Br-r-r-ip-ip-ip-ip--br-r-r-r-up-up-up--br-r-r-ap-ap-ap-ap-ap._ What
was it? Now from this side, _up-up-up-br-r-r-up-up_, and ending
abruptly. Then straightway from near the top on the other side,
_ap-ap-ap-br-r-r-r-ap-ap-ap_. Then fainter from half-way down the
street, and then from all points at once, a chorus of hammer-birds
making the bridge resound in call and in answer, hammer-birds with
strokes as swift as the roll of a drum. What is it?

And look! Those points of fire that glow forth here and there and vanish
as the eye perceives them, tiny red lights, tiny yellow lights, that
flash from far down the iron street and are gone, that flash from all
along the iron street and are gone! What are they? What strange work is
doing here?

[Illustration: "THE IRON STREET LOOKED DELICATE, NOT MASSIVE."]

It was the riveters driving the endless red-hot bolts that hold the
bridge together, driving them with hammers that you work with a trigger,
and aim like a fireman's hose, hammers with rubber pipes dragging behind
that feed in compressed air from an engine. Long past are the days when
bolts were driven by brawny arms and the slow swing of a sledge. Now the
workman, leaning his stomach against an iron club, touches a spring,
and, presto! the hard-kicking, pent-up air inside drives the darting
club-head back and forth, back and forth, quick as a snake strikes,
_br-r-r-r-r-ip-ip-ip-ip_, against whatever the steering arms may press
it. Driving rivets nowadays is something like handling a rapid-fire gun.
And how your body aches from the bruise of that recoil!

"We must get nearer to those fellows," said the artist; and presently,
after some mild hazards, we were safely over on the span, quite as near
as was desirable to a gang of riveters dangling twenty feet above us on
a swing. For presently, with a sputter of white sparks, a piece of
red-hot iron struck the girder we were straddling, and then went
bounding down--down--

"Nice, hospitable place, this!" remarked the artist, as we edged under
cover of a wide steel beam.

Crouching here, we watched another gang of riveters on the structure
opposite, where we had a better view, watched the forge-man pass al