een more than eighteen； younger than his son； Tim。
〃Ready to go； sir？〃 the pilot said。
〃Sure；〃 Norman said。 He was as ready as he would ever be。
Up close； the sub did not look like a toy。 It was incredibly massive and strong。 Norman saw a single porthole of curved acrylic。 It was held in place by bolts as big as his fist。 He touched them； tentatively。
The pilot smiled。 〃Want to kick the tires； sir？〃
〃No； I'll trust you。〃
〃Ladder's this way； sir。〃
Norman climbed the narrow rungs to the top of the sub； and saw the small circular hatch opening。 He hesitated。
〃Sit on the edge here；〃 the pilot said； 〃and drop your legs in； then follow it down。 You may have to squeeze your shoulders together a bit and suck in your 。。。 That's it； sir。〃 Norman wriggled through the tight hatch into an interior so low he could not stand。 The sub was crammed with dials and machinery。 Ted was already aboard； hunched in the back； grinning like a kid。 〃Isn't this fantastic？〃
Norman envied his easy enthusiasm； he felt cramped and a little nervous。 Above him； the pilot clanged the heavy hatch ＇＇48＇＇ shut and dropped down to take the controls。 〃Everybody okay？〃
They nodded。
〃Sorry about the view；〃 the pilot said； glancing over his shoulders。 〃You gentlemen are mostly going to be seeing my hindquarters。 Let's get started。 Mozart okay？〃 He pressed a tape deck and smiled。 〃We've got thirteen minutes' descent to the bottom； music makes it a little easier。 If you don't like Mozart； we can offer you something else。〃
〃Mozart's fine；〃 Norman said。
〃Mozart's wonderful；〃 Ted said。 〃Sublime。〃
〃Very good； gentlemen。〃 The submarine hissed。 There was squawking on the radio。 The pilot spoke softly into a headset。 A scuba diver appeared at the porthole； waved。 The pilot waved back。
There was a sloshing sound； then a deep rumble； and they started down。
〃As you see； the whole sled goes under；〃 the pilot explained。 〃The sub's not stable on the surface； so we sled her up and down。 We'll leave the sled at about a hundred feet or so。
Through the porthole； they saw the diver standing on the deck； the water now waist…deep。 Then the water covered the porthole。 Bubbles came out of the diver's scuba。
〃We're under；〃 the pilot said。 He adjusted valves above his head and they heard the hiss of air； startlingly loud。 More gurgling。 The light in the submarine from the porthole was a beautiful blue。
〃Lovely；〃 Ted said。
〃We'll leave the sled now；〃 the pilot said。 Motors rumbled and the sub moved forward； the diver slipping off to one side。 Now there was nothing to be seen through the porthole but undifferentiated blue water。 The pilot said something on the radio； and turned up the Mozart。
〃Just sit back； gentlemen；〃 he said。 〃Descending eighty feet a minute。〃
Norman felt the rumble of the electric motors； but there was no real sense of motion。 All that happened was that it got darker and darker。
＇＇49＇＇ 〃You know；〃 Ted said； 〃we're really quite lucky about this site。 Most parts of the Pacific are so deep we'd never be able to visit it in person。〃 He explained that the vast Pacific Ocean； which amounted to half the total surface area of the Earth； had an average depth of two miles。 〃There are only a few places where it is less。 One is the relatively small rectangle bounded by Samoa； New Zealand； Australia； and New Guinea； which is actually a great undersea plain； like the plains of the American West； except it's at an average depth of two thousand feet。 That's what we are doing now； descending to that plain。〃
Ted spoke rapidly。 Was he nervous？ Norman couldn't tell： he was feeling his own heart pound。 Now it was quite dark outside； the instruments glowed green。 The pilot flicked on red interior lights。
Their descent continued。 〃Four hundred feet。〃 The submarine lurched； then eased forward。 〃This is the river。〃
〃What river？〃 Norman said。
〃Sir； we are in a current of different salinity and temperature； it behaves like a river inside the ocean。 We traditionally stop about here； sir； the sub sticks in the river； takes us for a little ride。〃
〃Oh yes；〃 Ted said； reaching into his pocket。 Ted handed the pilot a ten…dollar bill。
Norman glanced questioningly at Ted。
〃Didn't they mention that to you？ Old tradition。 You always pay the pilot on your way down； for good luck。〃
〃I can use some luck；〃 Norman said。 He fumbled in his pocket； found a five…dollar bill； thought better of it； took out a twenty instead。
〃Thank you； gentlemen； and have a good bottom stay； both of you；〃 the pilot said。
The electric motors cut back in。
The descent continued。 The water was dark。 〃Five hundred feet；〃 he said。 〃Halfway there。〃
The submarine creaked loudly； then made several explosive pops。 Norman was startled。
〃That's normal pressure adjustment；〃 the pilot said。 〃No problem。〃
＇＇50＇＇ 〃Uh…huh；〃 Norman said。 He wiped sweat on his shirtsleeve。 It seemed that the interior of the submarine was now much smaller； the walls closer to his face。
〃Actually；〃 Ted said； 〃if I remember； this particular region of the Pacific is called the Lau Basin； isn't that right？〃
〃That's right； sir； the Lau Basin。〃
〃It's a plateau between two undersea ridges； the South Fiji or Lau Ridge to the west； and the Tonga Ridge to the east。〃
〃That's correct； Dr。 Fielding。〃
Norman glanced at the instruments。 They were covered with moisture。 The pilot had to rub the dials with a cloth to read them。 Was the sub leaking？ No； he thought。 Just condensation。 The interior of the submarine was growing colder。 Take it easy； he told himself。
〃Eight hundred feet；〃 the pilot said。 It was now pletely black outside。
〃This is very exciting；〃 Ted said。 〃Have you ever done anything like this before； Norman？〃
〃No；〃 Norman said。
〃Me； neither；〃 Ted said。 〃What a thrill。〃 Norman wished he would shut up。
〃You know；〃 Ted said； 〃when we open this alien craft up and make our first contact with another form of life； it's going to be a great moment in the history of our species on Earth。 I've been wondering about what we should say。〃
〃Say？〃
〃You know； what words。 At the threshold； with the cameras rolling。〃
〃Will there be cameras？〃
〃Oh； I'm sure there'll be all sorts of documentation。 It's only proper； considering。 So we need something to say； a memorable phrase。 I was thinking of 〃This is a momentous moment in human history。' 〃
〃Momentous moment？〃 Norman said； frowning。
〃You're right；〃 Ted said。 〃Awkward； I agree。 Maybe 'A turning point in human history'？〃
Norman shook his head。
〃How about 'A crossroads in the evolution of the human species'？〃
＇＇51＇＇ 〃Can evolution have a crossroads？〃
〃I don't see why not；〃 Ted said。
〃Well； a crossroads is a crossing of roads。 Is evolution a road？ I thought it wasn't； I thought evolution was undirected。〃
〃You're being too literal；〃 Ted said。
〃Reading the bottom；〃 the pilot said。 〃Nine hundred feet。〃 He slowed the descent。 They heard the intermittent ping of sonar。
Ted said； 〃 'A new threshold in the evolution of the human species'？〃
〃Sure。 Think it will be？〃
〃Will be what？〃
〃A new threshold。〃
〃Why not？〃 Ted said。
〃What if we open it up and it's just a lot of rusted junk inside； and nothing valuable or enlightening at all？〃
〃Good point；〃 Ted said。
〃Nine hundred fifty feet。 Exterior lights are