Hello Matt:

Can you explain the source and purpose of the mysterious, barely visible elevated "wire" that runs down the south side of El Cajon Boulevard, from 59th Street to Montezuma? It doesn't appear to be a power line or a cable, and it's easily missed unless the sun is reflecting off it. It almost looks clear. I was able to follow it about three blocks down Montezuma before I lost sight of it. Wazzup?

-- Kevin Naughton, Spring Valley

Hey Matt:

We were eating at the now defunct Cin City Chili at the corer of College Avenue and El Cajon Boulevard and we noticed a flash of light that hung in one place. When we went outside we discovered it was a fishing line or wire that went from lamp post to lamp post. I've seen it in other spots on El Cajon Boulevard and on Montezuma Road. What is it? The work of a frustrated angler? A lie to hang banners? Low-power antenna? Or did Spiderman come to visit?

-- Zak and Greg, San Diego

Here's a little insight into how the Team Matthew Alice machine works. We read questions, break for a snack; we brainstorm questions, break for lunch; re-read questions because we've forgotten them; break to help Pa Alice, who's folded up in his AbLounge like a meatball taco; re-brainstorm questions; guess at answers.

That's the typical scene, and it's been working for decades. But we have to admit, on this question we didn't even come close during the guess-at-answers phase. We had to do real research. Make real phone calls. Actually talk to people who know what's going on. None of us can remember the last time we had to do real work to answer a question. Even now, Grandma is applying cold compresses to the elves' foreheads to cool them down. Turns out the monofilament has nothing to do with fish or banners or Christmas decorations or transmitters or hanging laundry or anything like that. The monofilament marks part of the boundary of an Eruv (ee -roov). Of course, if you're not Jewish, you probably don't know what an Eruv is, so here's the scoop, with assistance from Rabbi Bogopulsky of Beth Jacob synagogue.

The Jewish Sabbath (sundown Friday to an hour after sundown Saturday) is reserved by religious law as a day of rest, ritual, and reflection. The Torah includes a huge number of rules about what can and cannot be done on that day; and the laws make a distinction between private space (e.g., a residence) and public space (streets, parks, and the like). One thing not permitted on the Sabbath is carrying things from a private space to a public space. Strictly speaking, in an Orthodox Jewish observation of the Sabbath, you can't even carry something as small as a house key or a Kleenex between these two areas. In the modern world, this restricts people from mingling with the larger population. An Eruv helps solve this problem and, according to the rabbi, helps unify the community, especially households with children and seniors. According to Sabbath laws, you couldn't push a stroller or a wheelchair between a private and a public space. Eruvis Hebrew for "joining together" or "mingling."

An Eruv is a type of enclosure, a demarcation that expands the definition of private space beyond the walls of a residence. It could cover many city blocks or many miles. The area can be defined by existing walls; but in any place where appropriate walls aren't already erected, a wire or string of some sort can serve to mark the boundary. That's what the El Cajon Boulevard monofilament is. It's virtually invisible and has a city right-of-way permit. Most major cities in the U.S. and internationally will have an Eruv. This is San Diego's first.

So there's the skinny. And speaking of skinny, we've gotta go help Pa Alice again. He got his T-shirt caught in the BowFlex and it shot him across the room.