A series of evening squalls have taken the pollen out of the air.
On the way home from dinner at a local restaurant we spotted a spectacular rainbow, visible along its entire arc once we found a good vantage point. There was a second, containing bow as well, its spectra ordered opposite to its companion. The brighter inner rainbow had a property I don't remember ever noticing before: at its inner limit (after violet) there were two additional spectra, closely packed and dominated by their own violet components, as if the rainbow has two small children clutching at its hems*.
This was the first rainbow our son has seen. I stopped the car, took him out of his seat, and pointed out the spectacle. I can't say for certain that he spotted the rainbow but he raised his hand alongside mine and pointed with me. He's only one, and everything is new.
As I started writing this the birds in the trees around our home were going bonkers, a sunset ritual this past week. They're calming down again now but I still hear one or two of them wooing for all he's worth.
* Addendum: I've done some research. Read on:
I pulled out my prized copy of Atomospheric Phenomena (W.H. Freeman and Company, 1980), a collection of Scientific American articles from 1949–1980. Chapter 7, "The Theory of the Rainbow," was written by H. Moysés Nussenzveig and originally published in April 1977. It describes the apparaition of the rainbow as follows:
The single bright arc seen after a rain shower or in the spray of a waterfall is the primary rainbow. Certainly its most conspicuous feature is its splash of colors. These vary a good deal in brightness and distinctness, but they always follow the same sequence: violet is innermost, blending gradually with various shades of blue, green, yellow and orange, with red outermost.[emphasis mine]
Other features of the rainbow are fainter and indeed are not always present. Higher in the sky than the primary bow is the secondary one, in which the colors appear in reverse order, with red innermost and violet outermost. Careful observation reveals that the region between the two bows is considerably darker than the surrounding sky. Even when the secondary bow is not discernable, the primary bow can be seen to have a "lighted side" and a "dark side." The dark region has been given the name Alexander's dark band, after the Greek philosopher Alexander of Aphrodisias, who first described it in about A.D. 200.
Another feature that is only sometimes seen is a series of faint bands, usually pink and green alternately, on the inner side of the primary bow. (Even more rarely they may appear on the outer side of the secondary bow.) These "supernumerary arcs" are usually seen most clearly near the top of the bow. They are anything but conspicuous, but they have had a major influence on the development of theories of the rainbow.
I love the name "supernumerary arcs," even if it is perhaps a little unromantic. "Alexander's dark band" is a great name too. I'm happy to have seen the former (and probably the latter as well, although I can't claim to have noticed it).
2nd Addendum: supernumerary arcs can be seen here. I found that link at the Wikipedia, which, no surprise, has excellent information on rainbows, with bibliographics references to the usual suspects: Minnaert, Greener, Livingston, and Lynch, the last of whom wrote the preface to the volume I referred to above.