Friday, March 24, 2017

On Being on dusting



A few weeks ago I got an email from one of the producers of On Being letting me know that Krista Tippett had used an excerpt from a blog post I had written for DotMagis during her interview with poet Marilyn Nelson.

Nelson is one of my favorite contemporary poets, in part because her work tangles with such a wide range of themes, from the desert fathers to modern Trappist martyrs, she is unafraid to draw on scientific imagery, and brings a unflinching eye to the gouges racism has left in our country.  I'm still haunted by Fortune's bones, or more precisely by the thought of Fortune's wife dusting her husband's bones.

During the interview Tippett tells Nelson:
"To that point — I don’t know if this is something you’re aware of — we found this blog post that was written actually by a professor who had just gotten back from sabbatical, and she was dusting her office. Have you read this? I mean, this is the things you can find on the internet. This is the upside of the internet. Is your poem, Dusting?'"
It reminded me of a story one of the Jesuits at the observatory told me about going into the Rome to pick up a piece of paperwork he needed that the government website had shown was ready. When he finally got to the window, he was told to come back.  "But it said it was ready on the internet," he pleaded.  But the Italian bureaucrat was unmoved, "The internet says many things.  Next!"

The internet does say many things, and so it was quite nice to hear my writing called part of the upside of the internet. It was also fascinating to hear a little bit of my own work read aloud, which Tippett does (you can hear it around 25:00 minutes in the segment).

In the "Case for Dusting" I suggested that the dust on my desk might have alien origins: "fragments ...burnt off comets that blundered into Earth’s atmosphere. Crumbs of the infinite lie scattered across my desk."  So I particularly enjoyed the recent piece in the New York Times about jazz musician Jon Larsen's work identifying the micrometeorites in ordinary, every day dust.  The photographs are gorgeous.  Now I really can't bear to dust my desk, knowing what I'm wiping away.



Saturday, March 18, 2017

Sliding scales

The Egg bought me this slide rule, I also have the somewhat 
more sophisticated K&E slide rule that my mother-in-law, 
Gai Hamburger Donnay, bought with them money she 
earned tutoring Jackie Robinson in chemistry during her 
undergraduate days at UCLA. The log tables are from my 
father's, in his CRC Handbook of Mathematics.
I've been playing with scales off and on for the last couple of weeks. Not musical scales, or pay scales, or sliding fee schedules, but logarithmic scales on a slide rule for an essay I'm writing about computational methods.  What do we use, what did we use, and how do these options affect what we do in research and what we teach?

As part of this effort I learned to add and subtract on a slide rule.  I mentioned this to a younger colleague who seemed unimpressed, why not, weren't slide rules just the equivalent of the calculator, instead of pressing buttons, operations were done by some sort of sliding algorithm?

Ah, but the miracle1 of using logarithms to do computations was that you could multiply two numbers by adding two numbers. To multiply two numbers, say 2378 and 3467, you looked up the logarithm of each in a table — 7.774 and 8.151 respectively — added them together (15.925) and found the number corresponding to this new logarithm to arrive at the answer:  8,240,000 (to 3 significant figures, the exact answer is 8,244,526).  Put in symbolic form LOG(A x B) = LOG (A) + LOG (B).  These "logs" didn't help with addition in any way.

But you can use multiplication to add in an admittedly roundabout way.2 To add A and B:
  • Divide A by B.
  • Add 1. (Ok, yes, this is addition, but trivial to do in your head).
  • Now multiply the result by B.
  • The result is the sum of A and B.
This is supposedly handy if you are mid-calculation on a slide rule and don't want to pull a number off to paper, then return to working the rest out on the slide rule.

With a bit of practice, I'm once again getting quick with doing equilibrium problems for general chemistry, faster mid-lecture than pulling out and unlocking my phone to use the calculator on it (and my last standalone calculator bit the dust this week, after a long, long, useful life.)  Then again, when I have a quadratic to solve, these days I can just say "Hey, Siri...."


There were other methods for doing multiplication of two number by adding two numbers based on trigonometric relationships, which led me to learn the word prosthaphaeresis.

I note that one should be impressed with the tables.  It took Napier 20 years of calculations to construct those tables.


1.  And a miracle they were thought to be from the very first, John Napier's book describing his invention (published in 1614) was titled  Mirifici Logarithmorum Canonis Descriptio (A Description of the Wonderful Rule of Logarithms).
2. For the algebraically inclined,  this translates to A+B = B (A/B + 1)

Friday, March 10, 2017

Factoring in change

The balance of my life is shifting again, neither Crash nor the Egg will be home this summer, one is doing math research on the east coast, the other stage managing a production of Macbeth in the west.  The last time Math Man and I had no children at home in a summer, we'd been married less than a year.  This coming fall we'll have been married for a quarter of a century. So it's been a long time, and things are shifting.

One marker of the shift is the pizza dough recipe, posted at the moment for easy Lenten reference on the hood of the stove.  It has pencilled in amounts  for 1 crust, a version for 2 (the standard recipe), for 4, for 6.  I've made it just for me, living solo, for us as a couple, for a family including teenaged boys, enough for snacks for a party of hungry teens.

It's such a tangible marker, the size of the ball of dough under my hands as I knead it before a quick rise. Like a family, it's a living, ever changing thing.  Growing and shrinking in turns, many possibilities caught in its web of proteins.  I miss the substantial feel of the larger ball, but take heart in knowing that the dough is rising in other places, too.