คำบรรยาย (252)
0:00(soft whimsical music)
0:01- [Derek] There is a limestone
cave in Western Virginia
0:03where one of its giant chambers
0:05has been turned into a musical instrument.
0:08They call it an organ,
0:10but it's like no other
organ on the planet.
0:14- [Derek] It relies on
electromechanical mallets,
0:16steel bolts, electric guitar pickups,
0:19and the main vibrating
material, limestone.
0:23It's more technically
referred to as a lithophone,
0:25the only one of its kind in the world,
0:28but people around here
just call it the organ.
0:31So Veritasium producer
Petr went to check it out.
0:35- We're going underground. Let's go.
0:38Can you tell me a little bit
0:39about the history of this place?
0:41- Luray Caverns?
- Yeah.
0:43- Discovered 1878, and, in fact,
0:44to your right is where they first came in.
0:48- Oh, no way.
- On August 13th, 1878,
0:52a group of hunters felt
a cool breeze coming
0:55from a small hole in the ground.
0:57Putting down their
rifles, they began to dig,
1:00making a hole big enough for the smallest
1:03of them to fit through.
1:04Andrew and Quint had
only a candle for light
1:07as they lowered themselves
down into the hole.
1:11They spent the next few months exploring.
1:15They kept finding giant caverns connected
1:17by narrow passageways.
1:19The ceilings and floors were covered
1:22in stalactites and stalagmites.
1:26They even found an underground lake.
1:29The cave system they had
accidentally stumbled upon
1:32turned out to be the largest
in the Eastern United States,
1:35covering 26 hectares.
1:38It's now known as the Luray Caverns,
1:40and it's visited by half a
million tourists each year.
1:45- [Larry] That's Dream Lake.
1:46- [Petr] How still that water is
1:47and the reflection is just
really something else.
1:51- The organ is one of the lower areas.
1:54It's in a room called the
Cathedral, a very large room.
1:58- [Petr] Yeah, that makes sense.
1:59- [Larry] And they used to
have dances down there, balls.
2:03They used to call it the ballroom
2:04before the organ was put in.
- Oh, no way.
2:05So in the 1920s, people
would go down here and have
2:08- Oh yeah.
- balls and dances and
2:10- Well, it was no-
- shindigs.
2:11- [Larry] It was a great place
2:12because it's air conditioned
basically naturally, so.
2:16- Yeah, that makes sense.
2:17Oh my God. Are you kidding me?
2:19No way. Oh, this is so gorgeous.
2:23(riveting instrumental music)
2:24And there's the control
panel for the organ.
2:27You're actually inside
the organ right now.
2:31The organ covers three and a half acres.
2:34All the notes are scattered out around us.
2:37Of course, this was started
in 1954, first played in 1957.
2:41- Okay. So it took
three years to get from-
2:44- Welcome to the
beautiful caverns of Luray
2:46in Luray, Virginia and particularly
2:49to the Great Stalacpipe Organ,
2:50which is located in this great
cathedral-like structure,
2:54which is 260 feet below the surface.
2:56This organ is so huge that
you stand not before it
3:01- [Derek] In 1954 while on a tour
3:03of the caverns for his son's
birthday, Leland Sprinkle,
3:06a mathematician who worked
at the Pentagon, had an idea.
3:11See, during the tour,
3:12the guide walked around
with a small mallet.
3:14He would occasionally hit a stalactite,
3:17producing a musical tone.
3:19This was the start of
Sprinkle's three-year project
3:22to turn the cave into
a musical instrument.
3:26- Since you asked for it, we
shall be most happy to show you
3:28how we make music from the
ancient stalactites around us.
3:32- What he did is he walked
around these caverns
3:35with a ladder and climbing
equipment and little mallets
3:38and little tuning forks, and
he would hit on stalactites.
3:41And then when there was
one that was close enough
3:44to concert pitch that he wanted,
3:46he'd take a disc grinder
and grind off the stalactite
3:50until it came to the pitch that he wanted.
3:53So this one should be middle C.
3:56(soft jaunty music)
(sound chimes)
3:59- Stalactites form very slowly.
4:02they grow at around 16 cubic
centimeters every 120 years.
4:07The rate is dependent on the
amount of water that flows.
4:10So some stalactites grow quickly
4:12while others don't really grow at all.
4:15They form as slightly acidic
water flows through the ground.
4:19It dissolves the limestone
and then redeposits it
4:22when it comes in contact with the air.
4:25As the water drips to the ground,
4:27it can also deposit the
limestone on the floor,
4:29leading to a stalagmite.
4:31Sometimes over thousands
of years, the stalactite
4:34and stalagmite can fuse
together, forming a column.
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5:39and now back to the cave.
5:42If you tap on a stalactite,
then like a tuning fork,
5:45it vibrates at its resonant frequency.
5:48That frequency depends on the size
5:50and shape of the stalactite.
5:52Bigger stalactites make lower notes,
5:54and it also depends on the
elastic modulus of the material.
5:58In this case, it's all limestone.
6:00So to adjust the resonant frequencies,
6:02Sprinkle shaved a bit off
the end of some stalactites,
6:06putting them into concert pitch.
6:09The organ wasn't connected to
the console when we visited,
6:12so Petr didn't get a chance to play it.
6:14But Rob Scallon, who has
a great YouTube channel,
6:16made a video about it a couple years ago.
6:19We asked him what it's
like to play a cave.
6:22- It's hard to describe the
feeling of playing a cave.
6:33It's very like grounding,
very surreal, very beautiful.
6:38You know, if I'm being romantic about it,
6:40you can hear the eons
and eons and eons of time
6:43that were needed to create this thing.
6:54The cave is, of course, huge,
6:56and all the notes are in different places.
6:58So some are further away. Some are closer.
7:00Some are amplified near you,
some aren't, and I love reverb,
7:04and the amount of reverb in
this room is just so immense,
7:08and the notes are so pure and beautiful,
7:10and they're in different places.
7:12So they like have different reverb.
7:13It's a very like hauntingly
beautiful type of sound.
7:25- As you can see,
there's also the solenoid
7:28that is basically a mallet.
7:30- [Leland] After the
tuning has been completed,
7:33we design a custom built bracket
7:34to which we attach an
electrically operated plunger.
7:38This plunger with its rubber
tip strikes the stalactite,
7:41causing it to vibrate.
7:43- [Derek] Since different
musical stalactites
7:45are far away from each other
and their volume variable,
7:48Sprinkle amplified the vibrations.
7:51He could've used microphones,
but in the 1950s,
7:53those weren't particularly robust.
7:55So instead, he borrowed
an idea from a piece
7:58of technology invented in the 1930s,
8:01the electric guitar pickup.
8:03(upbeat electric guitar music)
8:04A guitar pickup is a coil of
wire wrapped around a magnet.
8:08When a steel guitar
string vibrates near it,
8:10it interacts with the magnetic field,
8:12which induces a current in the wire.
8:14It doesn't work with
non-metal guitar strings.
8:18The thing that's vibrating
needs to be ferromagnetic.
8:21Sprinkle added a steel bolt to each
8:23of his musical stalactites
8:24and then used a pickup
to detect the vibrations.
8:27These signals are amplified mixed
8:29and played back through speakers.
8:31- You also gotta consider the weight
8:33of the bolt that goes into.
8:37- [Derek] But the guitar pickups
8:38created an unexpected
problem, radio interference.
8:43- I don't know exactly how it works,
8:44but one of the keys was picking
up a local radio station,
8:48which actually turned it into a sampler.
8:50It was a really fun part of the video
8:52and actually sounded pretty cool.
8:54That happens with electronic
instruments sometimes,
8:59(keys echo)
(muffled singing echoes)
9:03What is that? It happens
every time I hit that key.
9:05(keys echo)
(muffled singing echoes)
9:10I'm like turning on the radio.
9:13- [Man] It is picking up on that signal.
9:16- Oh my God.
- That is what it is.
9:20- So the radio is here.
9:23I thought, I'm like,
"Is that a human voice?"
9:27- That would be the AM radio.
AM station across the street.
9:30- [Petr] If they were
tuned in, you know, 1957,
9:34have they become longer
and hence gone out of tune?
9:39- Well, he tried to pick
stalactites that are inactive,
9:41that aren't growing anymore
is what he tried to do.
9:43- [Petr] But if he found
stalactites that were growing
9:45'cause I'm seeing like a
little bit of water, right?
9:47- Yeah, and you'll see-
- There's a little bit
9:48of growth happening.
- Right,
9:49and you'll see that,
and that comes and goes,
9:53but we've never had to retune one yet.
9:56- Like I love the idea
that there's an organ
9:58that could grow out of tune
- It could.
10:00- because of how stalactites grow.
10:03- I don't think it'll be in
my lifetime, but it could.
10:07- If he chose a bunch
that weren't inactive,
10:10it would be out of tune already.
10:13If they were completely
active, it would be.
10:15- That's so cool.
- It's very mad scientist.
10:17He definitely couldn't
get away with it now,
10:19like going into a place like this
10:21and then just starting to
shave off the stalactites
10:23that took eons to be created by nature.
10:26Thankfully it stays in tune
10:28'cause I can't continue shaving
off the parts of this cave.
10:32- This is just such a
strange and beautiful
10:36and kind of insane project
to take this gorgeous cavern
10:41and make it even more beautiful
10:43by turning into a musical instrument.
10:45- This structure has been
being created drop by drop
10:52for an unfathomable amount of years,
10:55and that's pretty awe inspiring.
10:59(electronic beeps trill)
(organ keys echo)
