It was hard to figure: how had that lobster found so much PCB on the Harbor floor, here? If he'd been hanging out along the shore of some fiasco property, or under one of their pipes, I could understand. But down here, there was nothing.

When I got to the scene of the crime, though, and flashed my spotlight, I was reminded that "nothing" is a relative term. Humans have been flinging garbage into Boston Harbour for three and a half centuries. I was standing in the foothills of Spectacle Island itself, staring around at everything from Coke cans to wrecked trawlers. Maybe, if I spent hours cruising the bottom, I'd find a cluster of fifty-five-gallon drums, thrown overboard by some corporation with too many PCBs on its hands. If I could do that, and trace them brick to the owner, I could go ahead and paint their logo on the prow of my Zodiac. I already had two logos there and was eager to become an ace.

But there were no drums sitting around within ten feet of me, and this wasn't the time for a full-scale search, so I scooped up some muck into a peanut butter jar. While I was screwing the lid down I shone my light into the sample and saw a condom spiraling through it. Reservoir tip, ribbed and used.

A chunk of latex could definitely queer my sample, so I had to abandon that one and take another. I swam around for just a minute or so, hoping I'd get lucky, then headed slowly for the surface. Upstairs the weather was turning to shit. I'd been out on the water since 7:00 A.M. and it was time for normal recreation.

One of my uncles grew up in New York and he used to tell me about diving for condoms in the Hudson. There was one stretch where you could dive down, holding your breath like a Polynesian pearl diver, and pick them off the river bottom. They'd dry them out, put them on broomsticks, dust them with talcum powder, roll them up, and sell them for a nickel. This was during the war and there were plenty of sailors in the market.

When I was a kid I'd wondered how those condoms had ended up in the river. Did the sailors peel off their used condoms, take the bus out to the West Side and fling them into the water, all in the same place? No. When I went to my current job I figured it out. The sailors flushed them down the toilets and into the sewers. In most of your old cities, you have combined sewers-one system carrying human waste, rainwater, and industrial crap.

But a sewer is just a collection of tubes that run downhill.

It's an artificial river, with tributaries and out outfall. A tube, like a river, can only carry so much stuff. Then it overflows.

There's no reason for a sanitary or an industrial sewer to overflow, because it gets steady, predictable inputs. Storm sewers are totally different. Take tonight, for example.

When I broke the surface, it was raining. The Zode was flashing and rocking like mad about fifty feet away. By the time I climbed in, which is pretty difficult when there's no one on board to hold it steady, the rain was coming down hard. I stripped naked, turned of the strobe, and just lay there in the rain until I started to shiver.

Sure, I'm a good environmentalist and I know that this rain was acidic because of coal-burning plants in Ohio, that it was carrying oxides of nitrogen because of automotive emissions from the Boston area. Maybe even a trace of nitrous oxide. But it was easily pure enough to drink. It was purer than I was, and there was no comparison with the sewage I'd just come out of. I could let it fall into my open mouth and not think for a minute about bioaccumulative toxins.

It was falling all over the Boston Basin, running into the sewers and heading for this Harbor. If enough of it fell, the sewers would overflow.

Sometimes, geysers of shit arise from downtown-Boston manholes after heavy rains. That's an example of combined sewer overflow. Normally it's kept under control. The engineers know that overflows will occur, so they have CSOfr- Combined Sewer Overflows-all along the waterfront. If the sewers get too much runoff, they overflow directly into the Harbor and the Charles. What comes out of those CSOs isn't just rainwater, though. Industrial waste and sewage are running down the same tubes. It all comes out together. If it's really bad, and even the CSOs can't discharge enough sewage to empty those tubes, that's when manholes start to pop.

There was a CSO near Castle Island Park. It explains why I'd found a condom out in the middle of the Harbor. There was probably a CSO in the Hudson River, in New York, upstream of my uncle's old condom-diving beds. Of course, he didn't have scuba gear. He just swam through the raw sewage

with his eyes open. He must have had the immune system of a junkyard dog.

I cut slowly through the rain back toward the yacht club, chopping through big rollers the whole way.

The visibility was next to nothing. So I was rather surprised when I came face to face with something big, shiny and blue, floating about a hundred yards from where I'd been diving. It was a boat, a good-sized powerboat, sitting there dark and quiet. And about the time I saw it, it saw me, and suddenly there was a tremendous whhooos echoed by a second one as its engines were started; the storm was drowned out by the sound of about a thousand horsepower digging a hole in the water. Its nose angled up like the prow of a star-ship, and it vanished into the night. No running lights. The only evidence it had ever been there was a clashing, foaming wake that knocked me around for a few seconds, and a high roar that dwindled to nothing in a hurry.

I realized kind of slowly, on my way back, that it was a thirty-one foot Cigarette. The same one I'd seen before, up in that channel, sitting idle on the water. And the son of a bitch was watching me. As the man says: just because I'm paranoid doesn't mean everyone isn't really out to get me.

For a second, I wanted to chase it down, try to see some identifying marks. Then I figured out why they were going to the trouble to use a hot-rod speedboat, a Miami penis-mobile, up here in this land of bankers' sloops and wallowing trawlers. Why they'd put nine hundred horses on its back, when it was only rated for six. They were using a Cigarette because it was the only boat in the harbor that my Zodiac couldn't catch.

Or to look at it another way, the only boat I couldn't get away from. That one didn't occur to me until a few hours later, when I was trying to sleep.

I took a long shower in the yacht club and then sat out under an awning, waiting for Bart to pick me up, watching yuppies destroy their umbrellas in the wind. I was wasted. But I was alert. If some Satan-worshipping heavy-metal dustheads decided to hurt you, or kill you, how would they go about it? The old multiple shotgun blasts probably wouldn't suffice. They'd want to cart me off somewhere,

make a ritual of it. For the nth time in my career I considered owning a gun. But guns were tricky and hard to aim. I should think in terms of chemical warfare-something really obnoxious I could use to slow down whoever came after me.

I had an idea already: 1,4-diamino butane; a.k.a., putrescine-the distinctive chemical scent given off by decaying corpses. I could whip up a batch and carry some on me. That would give anyone second thoughts.

When Bart pulled in, he cranked up a Poyzen Boyzen tape and I half-breathed all the way home-half a breath of air, half a breath of nitrous. Phoned Debbie and Tanya to make sure they were all right. Tanya's boyfriend was holed up there, answering the phone, and armed. He was into some kind of martial art that involved samurai swords, so I felt better. I took another shower and then started drinking. Bart and I sat in the living room watching the Stooges on Deep Cable until about two in the morning, and I think Amy came over, though I never heard a single moan, shriek or wail. Roscommon drove through sometime during the night and sideswiped Bart's van, streaking it with white paint.