by Pepper White
The card catalog was compact; it all fit within the space of several washing machines. It was smaller than the card catalog in the humanities library.
Okay. Let's start with "balloon." Maybe someone's done a thesis or written a book about it. Let's see. Ballistic missiles; ballistics, exterior; here we go: balloon.
"A 2-Dimensional Model for the Inflation of a Limp Intra- aortic Balloon." "The Occlusive Filling Problem-see Heart." "Balloon Behavior in Restrictive Fluid Environments." All these reports are talking about hearts. I don't care about hearts; I need to know about real balloons.
Next step. Maybe it's in a thermo book. Look under T. "Thermal Pollution." "Thermonuclear Devices." "Thermodynamics." Here's an interesting one: "Reflections on the Motive Power of Heat and on Machines Fitted to Develop This Power," by Carnot. Carnot was the nineteenth-century Frenchman Gyftopoulos always talked about. Even though Electrical Engineering, Course Six, double E, is the hot topic at the institute now, the double E's would be nowhere if it weren't for the mech E's like Carnot and Diesel, who made the shafts turn the generators. Most of the thermo books had the same call letters so I'd camp out in that section of the stacks.
The balloon problem involves "Differential Equations, Nonlinear," so I also wrote down the call letters for that section. And just for good measure, I looked up "Fluid Mechanics." On to the seventh floor.
Barker is shaped like a big doughnut. The doughnut hole is the domed space in the center where you read the funnies and sleep in the leather chairs. The fried dough is the large-radius circular hallway on the inner edge of the stacks. You can walk the loop, almost not perceiving that you're turning, and end up where you started. But if you're alert you're different at the end of every lap.
Differential equations and numerical analysis techniques books were useless. They all were a bunch of lifeless Greek letters like sigma and subscripts like i. I remembered Professor Kollman in Belgium telling me that a "mathematician writes out an extremely long and complicated solution to a problem, with, say, one or two hundred logical or algebraic steps. Then he or she condenses it into the shorthand of mathematics with all its Greek letters and subscripts and superscripts, and publishes it in a form that no one else can understand." That was why I was neither a mathematician nor a physicist.
In the doughnut I felt I was in the same mental marathon with Bernoulli and Newton. OK, their mile times are under five minutes and mine are over ten minutes, but it's still the same race. The crowd is the same and the pain is the same and maybe all of us will make it to the finish line. I had the advantage of a library and packed ground before me.
Next stop. Fluids texts. Useless again. Many looked as obscure as the mathematics texts-lots of subscripts.
Last stop. Thermo. Ditto except for one text: "Practical Thermodynamics," published in England. It didn't solve the problem, but it had one that was close. One example stated, "A common problem in industry is filling a small tank from another vessel in which the pressure of the larger vessel is assumed not to vary as a result of the process. Tapping fluid off a pipeline of liquid or gas is a real-world example of such a process." So Greene knew what he was doing when he gave me this problem.
Other than that the library was a dead end, but I still learned. Each field's textbooks had nearly identical entries in their index sections. The presentation order varied, but within a given field each book said more or less the same thing. The set of knowledge is finite, manageable. That's why the Barker card catalog is so small.
My bicycle tire was flat that evening so I took the bus home to Allston. I jotted notes, thoughts that had come to me while I looked through the library.
I reviewed the equations:
The force balance on the balloon shell; Bernoulli's equation for the flow into the balloon; Flow continuity from the tank to the balloon.
I checked off the problem's constants, as Greene had suggested. These will go along for the ride in the analysis, and later on they can vary. The trick now is to make the equations flow.
Think. If I can solve my equation for the speed ("dx by dt, or xdot") of the skin of the balloon, I can multiply that d by dt by a little dt and find a new position of the skin. In my equation that balances the air pressure force with the balloon elasticity, a new skin position will give me a new balloon pressure, which will in turn give me a new skin speed, which will in turn give me a new skin position, which will in turn give me a new balloon pressure, et cetera, et cetera, et cetera, until the balloon breaks or the pressure in the balloon equals the pressure in the tank.
In freshman calculus the trick was to take long, curvy lines and make them into short, straight lines. I want to graph x, the balloon position, versus t, time, using little slices of time.
I redrew the picture I remembered from calculus.
I could call NextX = x plus dx/dt * dt.
Time to write the software.
The Apple handbook explained a "for" and "next" loop. This is the heart of how a computer solves things "repeatedly."
I'll create an index, call it I, that's a substitute for t, time. Time is just a place holder, a reference mark, a hash mark on a graph. If only there were more of it.
I'll say "for I = 1 to 100," as if I want to track the balloon for 100 1-second intervals. At the beginning of each second, I'll calculate the speed of the shell of the balloon. I'll multiply that speed by 1 second to find how far the balloon goes in that second. That will give me the next position. I can taste the solution now.
One last problem. How do I tell the computer that I want the time increment always to be 1. If I'm at second number 43, how do I know to multiply by 1 and not 43? There's got to be a trick.
There is a trick. At each step, define a last step. For example, if I'm at step 43, the last step will be 42. The step size will always be one. In the program I'll call the last step "last!" (computerese for "last I"), and the program will start with last! equal to zero. I'll calculate the balloon pressure, the speed of expansion, and the new size of the balloon (x) by programming
Then I'll make the present I (1) equal to the last I, so when I go on to the next 1 (2), I'll get 1 by subtracting the last I (1) from the present 1 (2). The program for the Apple will be:
It's so simple. How did it take so long for me to arrive at the solution?
I looked out the window of the bus. I'd stayed on it for three miles past my stop, and it was turning around at Watertown Square. Space and time had collapsed in thought.
August 25
I showed my solution to Greene and he said, "That's fine. I'll give you a B if you stop now. If you want an A, though, I'll give you another week, and you can change the model to accommodate the case where the skin of the balloon has mass."
No problemo. I made a slight change to the program and left the solution on his desk four days later.
September 2
I wore my, or rather Don's, lab jacket around the institute. It made me feel a part of the place. The scared faces of the newcomers further fed my confidence. I bolted up the stairs to Greene's office to receive my A.
Greene's secretary had put on thirty, maybe forty pounds, and she bobbed a stopwatch on a string back and forth to prevent herself from running down to the machine in Building 6 to get a pack of Camels.
She pulled out my file. "You got a B," she said.
That snake. I did the extra work and he gave me a B anyway. If he'd given me an A, the A would have canceled out one of the C's from the first term on my grade point average (GPA). I don't care how many high-level contacts he has. We made a deal and he was backing out of it.
"Is he in now?" I asked.
"Yes, would you like to see him?"
"Yes. Right away."
I went in. He was sitting at his desk, glasses on, reading proceedings from a meeting of the National Academy of Engineering. He stood up to greet me.
"Why'd you give me a B? I thought we had an agreement."
We both stood still, on opposite sides of his desk.
>
"Yes, we did, but in the end, even though you made a good effort at solving the additional piece of the problem, the write-up you submitted, well, it just didn't have the polish of what I could in good conscience call 'A' work. I could let you look at copies of some term projects I've given A's on, and I think you'd agree."
"But why didn't you tell me, give me a chance to do more work, to fix it?"
"Well, there comes a time when you just have to close the books on a project. You've done good work, just not A work. I'm sure just one B won't bring your grade point average down that much," he said. He must have thought I had mostly A's. In a convoluted way he'd just given me a vote of confidence.
"Yeah, well, it won't help that much either. Maybe you're right. It's time to cut my losses and press on."
I'm off probation.
I belong here.
C H A P T E R
11
Sigma Delta
Schedule:
Fall '82: 2.70 Introduction to Design (Wilson)
2.14 Feedback Control Systems (Brooks)
2.996 Thesis
September 3
"Is this Pepper White?" the voice at the other end of the phone said. "I'm calling from the Dean of Student Affairs' office. An opening for a tutor has just come up, at Senior House. Would you be interested in interviewing with the housemaster?"
"Sure. What do I have to do?"
"Just call Professor Dorsey at Senior House; his number's in the directory. You can set up an appointment with him."
Yeah baby. Maybe there's a chance for a tutor position after all. A tutor at MIT is what state schools call an R.A., short for resident assistant, and what Harvard calls a house fellow, because Harvard likes to give important sounding names to people.
In the springtime between bicycle rides I'd applied for tutor positions at several undergraduate dormitories: at MacGregor, where the tutor suites have million-dollar views of Boston; at McCormick, the all-women dorm where the fundamentalist families send their daughters ("Hey, maybe their boyfriends need counseling," I said to the housemaster); and at Bexley, the acid rock dorm across Mass. Ave. from Building 7. At Bexley, rumor had it, the chem majors synthesized their own LSD, and the FBI was just aching to make a bust. At Bexley, I made it to the first round of tutor elimination.
April 1
The interview consisted of the twelve tutor candidates sitting around the living room of the housemasters, Professor and Mrs. Jacob Levy. None of the candidates, if they thought like me, would be very disappointed if the other eleven were run over by a dumptruck at the Mass Ave. crosswalk. About thirty of the one hundred Bexleyites asked general questions. Our job as candidates was smoothly, deftly, to answer a question at an appropriate time of our own choosing.
The kid wearing the Led Zeppelin T-shirt posed the question, "So, like, if I were on a bad acid trip, like, and if you found me, like, what would you do?"
It seemed as good a time as any for me to speak up. "Well, your business is your business; I mean if you want to fry your highly gifted brain out, go ahead. I'll call an ambulance and get you to a hospital where they can take care of you, maybe pump your stomach out, and keep you from hurting yourself. As for myself, I haven't taken so much as an aspirin for about eight years, and I've been fairly healthy and happy."
Buzzer sound. Wrong answer.
The biochem major sitting next to me, with longish hair, beard, and mustache, hit the mark a little closer.
"Well, I've done about every kind of recreational pharmaceutical there is, and I've got a notebook full of recipes, which might come in handy for you guys, heh heh. As far as the acid trip scene, I'd like talk you down like I once did for a friend of mine. I'd say something like, 'It's OK, you're coming to the runway, you're not going to crash and bum, man, just go easy with the stick, nice and smooth, we'll get you down, that's it here we go it's all right.' I'd say something like that until you came down off it."
Buzzer sound. Right answer.
September 3 again
My appointment with Professor Dorsey was at seven and I took the scenic route to Senior House-down the Charles from Mass. Ave. The sailboats in the late evening sun and the real world of Boston's skyline in the background made me think back to the year before, when I was a technological infant. I'd gotten better; I knew it. Now if I could just talk my way into being a tutor I'd be able to pay my debts.
There was a little chill in the air, and it made me remember the fall in Brussels, and Stephanie. I hadn't called or written since December, and neither had she. Water under the bridge in Bruges. I wondered whether she'd found someone else.
Into Senior House's cornerstone was chiseled "1917." In 1917 my mother's father marched across Flanders to Paris. Past the glass entryway to the courtyard enveloped by the L-shaped dormitory and the wall of President Gray's backyard, Jimi Hendrix played "Purple Haze" loudly on speakers pointed out of a fourth-floor window.
The fast-falling dusk was made darker from the shade of the trees in President Gray's garden, lighter by the light of the bonfire ahead in the courtyard under the tall tree. A kid with long hair and lots of zits and a black T-shirt with "Visit Hell" written underneath a flaming design of Building 7 walked past toward Ames Street. I said hello.
He returned no response, no nod, no noise, no acknowledgment of my existence.
Two women walking arm in arm also ignored my greeting.
A tall guy wearing a ponytail, an earring, and a garment that is wom by some Indian men but we in America call a skirt said hello. I didn't say hello.
Near the fourth-floor window, where the speakers played Hendrix, the larger-than-life version of Mary's "Sport Death" T-shirt hung from the balcony. The skull, the stars and stripes, the "Only life can kill you" in the skull's teeth, waved gently in the bonfire's breeze. This place is even worse than Bexley, I thought.
Another guy with a ponytail spun around the tree from the tire swing. He arched his back horizontally outward from the tire, and the centrifugal force thrust his ponytail outward as he missed the bonfire by a hair's breadth and his head never came near the tree; he was a tetherball with an on-board microprocessor. He'd probably calculated his trajectory on his computer and knew precisely what his margin for error was.
"Yeah, Sport Death!" one of the bonfire bystanders said. Sport was a command-to defy, to taunt. The bystander wore a yellow T-shirt that said, "Dare to be friendly," and I asked him for directions to the Dorseys' apartment.
"Sure, it's right down there on the left toward the river, on the second floor of Crafts," he said with a happy tone to his voice.
I sat down with Professor Dorsey and he explained the situation. "Well, you see, the Atkinson tutor was off doing some genetic engineering research in the Australian outback for his thesis work at the Whitehead institute, and he contracted some strange disease out there and is under observation in a hospital in Sydney."
"Gee, that's terrible; I hope he recovers." But not real soon.
Professor Dorsey continued, "Freshman rush week is coming right up, and the students aren't back yet except for a few. Typically, it's a pretty wild time, and to keep the whole place from blowing up, I think we really need our full complement of tutors."
"I thought it was all seniors; isn't that why they call it Senior House?" I asked.
"No, it's the senior house, the oldest dorm in the institute. There are all classes here, and also some graduate students. Part of the issue for rush week is that this place is usually the freshmen's last choice-it's generally a tie between here and Bexley. Nobody wants to live here; they'd rather live at the more middle-of-the road dorms like Macgregor and New House up the river, or at the frats; there's even been talk about shutting down Senior House as a dorm. So we'd really like to have as many tutors on hand as possible, just to keep an eye on things and to be a friendly face for the lost freshmen."
"I think I could handle that," I said. "Are you interviewing anyone else?"
"Well, you're the first person who's
called, and the dean's office wasn't able to reach anyone else today. You seem like a nice enough person; I think you'd be fine. I'd just like to ask one question of you, though. Where'd you go to high school?"
Kind of an odd question, I thought. "Winston Churchill High School, in the Washington, D.C., area," I answered.
"Good. That's a relief. What with the blue and white striped shirt you're wearing, and the khaki pants, and the topsiders, I was afraid you might be a preppy. I don't think a preppy would get along well here. When can you move in?"
"Tomorrow," I said, happy at the prospect of leaving my sloping tenement in Allston.
"That's great," he said. "Now let me briefly summarize your duties as a tutor. First of all, the term is pretty much a misnomer because, well, frankly the undergrads are generally smarter than the graduate students, except for the ones who went here as undergrads and the ones who came here from Cal Tech. Besides, the students who have friends tend to tutor one another, or they get help from someone who took whatever class it is the previous semester. Your main purpose as a tutor is to make the environment in the dorm a little more human, and to be on the front line of knowing whether anyone is having emotional problems," he said.
"Uh huh."
"You see, we're in a sticky position here; on the one hand the undergraduates are allegedly adults and are accorded all the freedoms of normal society. On the other hand, many of the undergraduates spent their spare time in the computer room at their high schools so they didn't really have a chance to develop socially. And Lord knows there's no time for them to develop socially here. So if one of them goes over the railing and through the ice in the dead of winter, there's a good chance that his parents will sue the institute for all it's worth. Part of your job is to help us prevent that from happening. Oh, and by the way, we'd like you to host a study break every two weeks, and once each term you'll be required to host a whole-house study break."