Many years ago, I heard of the great work
(Wilhelm Braumüller, Wien und Leipzig, 1922)
by J. M. Pernter and Felix M. Exner. It was reputed to be the reference on halos and other phenomena of atmospheric optics. For years I looked for a copy in vain.
Back in the middle 1980s, the Astronomy Department here got an offer from the widow of a local optical worker who had recently died. He'd left a basement full of optical parts — dozens of cigar boxes full of finished and half-finished lenses and prisms, left over from work he'd done for the Navy in WW II. We could have the optical stuff if we wanted it.
Besides the optical parts, there were a few books. One was a very beat-up copy of Pernter & Exner. The widow let us have some of the books, including P&E.
This copy turns out to have originally belonged to Fritz Roßmann, a meteorologist who was at the old airport in Munich; it has his bookplate inside the cover, which has fallen off. Roßmann gave it to E. P. Martz, Jr.
I knew of Martz because he had done some of the early work on the clouds and atmosphere of Venus back in the 1950s. At the time of the gift, he'd been here in San Diego, working at the Visibility Laboratory of the Scripps Institution of Oceanography, out on Point Loma.
Because of his work on atmospheric optics, Martz moved to the Jet Propulsion Laboratory in Pasadena, where I'd worked in the late 1960s. I was eventually involved with the discovery that the “clouds” of Venus are a dilute haze of sulfuric-acid droplets, similar to the stratospheric aerosol on Earth that produces beautiful red volcanic sunsets (see the Meinels' book for details.)
Somehow, the book went from Pasadena back to San Diego; maybe Martz knew our optical benefactor in his Navy days?
On examining the book further, I found there were numerous notes pencilled in the margins, mostly in old German script (the kind that's so hard to read). I assume these are in Roßmann's hand. Some refer to work done at Scripps by Cox and Munk in the 1950s.
I didn't pay much attention to these notes at first. But when I became involved in the Navy project to study sunset optics, I noticed that several seemed to contain useful references to interesting papers not mentioned by Pernter & Exner. So it became necessary to get these marginal notes deciphered.
The natural first place to turn was the local German Department. I took the book over there, and showed the notes to one of the faculty members. “Oh, this is very difficult,” was her response. Well, thanks; I already knew that. So I turned elsewhere for help.
As usual, the library was the basic resource here. First, I figured I could probably find out how to read German script from some book there. Sure enough, the Brockhaus encyclopedia has an entry (“Deutsche Schrift”) that illustrates the alphabet, both in caps and lower-case letters. The only catch is that what's shown in the encyclopedia bears about as much resemblance to actual handwriting as those idealized script letters you used to see above the blackboard in grade school did.
Even so, I was able to puzzle out several useful references, including Gehler's Physikalisches Wörterbuch. I also found a reference to Emil Schnippel's remarkable account of a very complex sunset display — perhaps the finest on record.
Some years after this much-travelled copy of Pernter & Exner fell into my hands, I found myself flying to Munich, and landing in the old airport at Rheim where Roßmann had been stationed. More recently, in my work on green flashes and mirages, I've come across a few of his publications. His interest in atmospheric optics explains the annotations in his copy in P&E.
They say it's a small world; but who would have thought it this small? I think this tangled tale shows just how small the world of science and technology really is. The connections here are in fields as apparently diverse as astronomical photometry, atmospheric optics, technical optics, meteorology, and planetary atmospheres; the common element is the propagation of light in planetary atmospheres. It's just another example of the way things are interconnected in the sciences.
© 1999 – 2007 Andrew T. Young
If you have comments, please let me know.