My father was an engineer who died before the advent of pocket calculators, personal computers, and smart phones. Often when he came home from work, his slide rule was still nestled in the pocket of his white button-down shirt. I am embarrassed and even a bit ashamed to admit that I have never used a slide rule and wouldn’t know what to do with one. Even though I was quite good at math, I avoided calculus and chemistry and never learned to use a slide rule.

If I held one in my hand, I would treat it with respect and curiosity. Not as playful as an abacus with its sliding beads capable of making music when shaken, a slide rule by its silence and straight edges seems a sober sort of tool. But nonetheless possessing a certain sort of beauty, with its numbers so small I might now need a magnifying glass to read them. And that center panel that slides to line up universes of possibility–imagine holding the secret solution to so many puzzles!

In the old black and white photograph my father sits on a folding summer chair on our generous porch high above the ground that fell away from the ledges on which our house was built. The neighbors’ trees in the background are smaller than I remember them. The house in the far distance at the top of our neighborhood hill was less than a quarter mile from the house where my father was born.

The sleeves of my father’s white Oxford shirt have been neatly rolled to his elbows. His face is turned downward toward his hands. His long slender fingers hold the slide rule gently, gracefully, as he works some calculation that will likely be recorded on the back of an envelope in small, tidy figures.

His handwriting is neat but not fussy. He signs his name with one modest flourish at the end, so that the tail of the “s” on Curtis swoops around counter-clockwise to cross the “t.” Then his hand lifts to dot the “i.”

My father has been dead so many years I nearly clutch my heart when I come upon his handwriting–those unmistakable tracks made by his own hand. Some days I bend down and put my lips to the inked letters to kiss them, or hold the lettered paper against my heart.

*I wrote this piece with this photo in mind but not in front of me. I’m not sure my dad is in fact holding his slide rule in this photo, but it doesn’t really matter.