old age n. phrase In human life, the years reckoned to lie beyond 60 (obsolete).  Replaced mercifully by senior citizenship.

Engineering education in the early fifties was all slide-rules and tabulated formulas, kind of a trade seeking to be ranked among the loftier professions.  In my first semester at El Camino College, I came under the influence of a dedicated physics instructor, Tom Wilson.  He determined to draw his engineering students out of the shadows of empiricism into the full sunlight which is science.  He became the favorite instructor of my entire graduating class.

A long time later, I was planning a trip to California to visit my daughter, who was then studying to be a teacher.  I wanted her to meet Mr. Wilson and was calling from Connecticut to set it up.  His assistant answered the phone and recognized my name at once.

Permit me to tell that story.

Tom Wilson's teaching style applied a droll form of cumulative humor.  "This is truly a time to say 'Aha'," he would say in a flat voice, following a mathematical proof.

One day, he mentioned that "a nine-year-old child would divide both sides of the equation by coefficients of the unknown as follows..."  No one noticed.  Later he made an offhand assertion, "a nine-year-old child would perform the indicated algebraic manipulations..." which produced a few chuckles from the class.  References to a nine-year-old child appeared about once a week, each time taking us by surprise.  We began to laugh out loud.  The statement of a problem in a quiz might begin: "A nine-year-old child is rolling a cylinder up an inclined plane..."  As the semester went along, physics got harder and the nine-year-old child got smarter.  And we laughed louder.  You had to be there.

Shortly after I graduated, my brother David reached the age of nine, and -- you can see it coming, can't you.  I taught him a few physics formulas and arranged to have lunch with my former instructor.  While the three of us feasted on cafeteria meatloaf and cold peas, I gave the signal.

David put down his fork.  "Every particle in the universe is attracted to every other particle," he said, "by a force which varies directly as the product of their masses and inversely as the square of the distance between them."

Tom Wilson smiled politely, only somewhat astonished.  Suddenly it dawned on him.  "How old are you, David?"

"Nine, sir."

Wilson glanced at his watch.  "Finish your lunch and come with me," he said.

Behind Wilson's lectern was a sliding half-door, beyond which was a storeroom, the repository for all the wondrous physics gadgets he used in demonstrations.  Unknown to the students that afternoon, my brother David was standing behind the door.  I sat in the back of the room and watched Tom Wilson give his lecture.

"We will need to take into consideration the Doppler Effect," said Wilson at one point.  "Which, as a nine-year-old child knows, is as follows..."  Mr. Wilson began writing an equation on the blackboard but turned abruptly as laughter filled the classroom.

"Perhaps," said Wilson, face crimson, "you doubt that."

A grinning student in the front row gave a mock assurance on behalf of the others, "Not at all, Mr. Wilson, we believe you."

"Something tells me you do not, but I can prove it!" Wilson exclaimed while striding briskly across the room.  He lifted the sliding door with a flourish.

There stood David, arms folded.  "The apparent wavelength of sound or light," he said with a straight face that would come to serve him well throughout his life, "depends upon the velocity of the source and the system with respect to which it is measured."

Wilson slammed down the door and erased the blackboard.  Order could not be restored.  Classes had to be cancelled throughout the building.  A legend was created.

"He and my other brother are both ministers now."

The young man chuckled.  "Does he still know 'F = ma'?"

"Probably not," I replied.  All at once I was struck by a devastating fact.  I performed the arithmetic in my head: The Nine-Year-Old Child incident must have taken place before this fellow on the phone was born.

I have since taken comfort in another devastating fact: Members in my age group constitute the one minority to which all persons aspire.  Think about it.