Milton Caleb Stuart was Chairman Emeritus of Lehigh University’s Mechanical Engineering Department and a recognized authority in his field, having authored textbooks on thermodynamics and steam power plants. Silver-haired, he always wore a suit and tie in class. He seemed to like his students, and the feeling was pretty much mutual. I liked his class and certainly didn’t need a reminder to do the homework, or so I thought.
When one of us raised a question, his answer was often unpredictable but salient. On the last day before graduation, someone asked, “Professor Stuart, how do you think we should go about getting our first job as a graduate engineer.”
“Decide where you want to live, go there and look for work.” At the time, that seemed like useless advice. Years later we would realize the man had a point.
Professor Stuart was opposed to our memorizing material. Rather, he wanted us to learn the fundamentals and work from that knowledge. One day, to illustrate this, he drew a large “X” on the blackboard. “Name a cycle.” We all knew what was coming; he would draw a cycle diagram in an unusual way to illustrate that we didn’t need to memorize thermodynamic cycles if we could just think our way through them.
“Stirling,” someone said. Quiet chuckling followed; the Stirling cycle, not in general use, was the most obscure one we knew. The quiet laughter spread as one by one, we realized the game was on. We would make this as difficult as we could.
“Give me a property.”
“Entropy,” came a quick reply. The laughter grew; entropy was a bit of a nebulous concept to us.
“Now another.”
After a moment of silence, someone said, “Specific volume.” Gleeful guffaws broke out. It was a silly idea; a useless graph would result, and it wouldn’t be easy to think it through.
“What polarity would you like for the axes?”
“Both positive down,” one of us said. There was more laughter. No mercy. Now our professor would have to create an unprecedented diagram, and draw it upside down. To our amazement, he did so without hesitation. As he went through the various parts of the cycle, he explained why lines went in the direction they did and why they were curved the way they were. By the time he had finished, our laughter had given way to sober awe. He certainly did make a convincing demonstration.
Professor Stuart conducted class much as a showman. He would ask a question and then call a student, by his last name, to answer. If the good professor didn't like the answer, he would simply say, "No, no," and call another name. When getting a good answer, he would say, "Stand up." When the student rose, Professor Stuart would go to him and shake his hand. He would then make his way back to the head of the class and discuss the question. Such was the routine. He was always down to earth. In one case, while discussing boilers, he asked, “Mr. Abbott, how big is a boiler?”
“It depends…” began Abbott.
“No, no,” said Professor Stuart. “Mr. Jamison, how big is a boiler?”
“Well it does depend …” Jamison protested.
“No, no, it doesn’t ‘depend,’ it doesn’t ‘depend,’ ” growled the professor, treating the word “depend” contemptuously. Well, of course the size of a boiler does depend; it depends on the rate at which it raises water to steam and to what temperature, but our instructor obviously wasn't satisfied with that. He then called on John Redmond, who looked too big and muscular to be very bright, but probably was as smart as most of us. "Mr. Redmond, how big is a boiler?"
Redmond knew full well the size of a boiler depended on it's rating, but with that answer having just been twice rejected, he raised his voice in desperation and simply said, "Pretty damn big."
"Of course," said Professor Stuart, "stand up." The handshake ensued. "You people have been on field trips to three different power plants. You didn't notice that? Boilers are pretty damn big." None of us would ever forget how big a boiler is.
My roommate and I shared a small room in a private house that also housed eight other students. He and I were compatible. In fact, for most evenings for three years, we sat facing each other across a small worktable doing our homework and never had a significant disagreement. We pretty much thought alike. Both car guys, we preferred sports cars to Detroit iron. He was more aggressive; I more laid back. He had a 600cc Triumph motorcycle; I made it through college without wheels. Had we been old enough for the Air Corp in WWII, he might have made a great P-51 pilot. I would have wanted that, but more likely would have been stuck as a navigator in a B-17. He was raised Catholic and I Methodist, but neither of us was superstitious. He had a crewcut, so we called him "Curly." I went with conventional combed hair. Most of us in the house had gotten in the habit of calling one another by our last name spelled backwards, so I was "Treblig." We sat side by side near the front of Professor Stuart's basic thermodynamics class.
Now we are approaching “thermo” with a mutual friend, Dan, who asks, "So you guys know all there is to know about enthalpy?"
"What is it?" I ask.
"Enthalpy."
"Enthalpy? What's that?"
"Apparently you have not done your homework," drawls Dan.
"Oh my god, I completely forgot." It’s not like me to forget an assignment. I might gloss over one or simply decide not to do it, but forget to do it? No. And I would never give short shrift to an assignment from Professor Stuart. "What page is it on?"
Dan turns to his bookmark. "Fifty seven."
In desperation, I quickly turn to the page in my book and scan the few pages in the section. It's all text except for a single equation: h = e + pv. I know what e, p and v are and so h must be enthalpy. Now time has run out, we are entering the classroom, so I quickly close the book. I had spent no more than five seconds preparing for class.
Professor Stuart starts the class by asking, "What is enthalpy?"
Don't call on me; all I know is that one equation. Well, the odds are in my favor; I'm just one of about twenty in the class.
"Mr. Zimmerman."
C’mon Big Z, you know it.
"Enthalpy is a measure of the total energy in a gas."
"No, no." Then after a pause, " Mr. Ellison."
OK, Ellison, give him what he’s looking for.
" It's the amount of useable energy in a gas."
"No, no". He looks over in my direction. "Mr. Gilbert."
Damn, so much for the favorable odds. Maybe he saw me trying to look invisible. All I can do is recite the equation. Well, here goes, "Enthalpy is the sum of internal energy and the product of pressure and specific volume."
"Of course. Exactly right. Stand up." Professor Stuart comes over to me and we shake hands. He turns and goes back to the front of the class and I sit down. "Didn't you people read the assignment?"
I sneak a look at Curly, expecting something like a sad smile and a slow shake of the head. Instead he gives me a theatrical icy stare, heavy eyelids, the whole bit: pure, cold hatred. Curly could have made it big in Hollywood. I'm so surprised by that face that I almost burst out laughing.
After class, Curly and Dan walk away. I catch up with them. They're quiet. I'm feeling good. I break the silence with "Enthalpy… no big deal."
"Shut up," says Curly.
"Shut up," echoes Dan. It's their way of congratulating me. Then I remember the look on Curly’s face and start laughing.
Back at the house, I make a homework schedule and tape it to the wall next to my side of our worktable. I rarely need it, which is to say, of course, I do need it.
Richard R. Gilbert © 2010
