Rescue

incomprehensible question about Boyle’s Law, which has something to do with temperature, the air in your tank, and water pressure. I say “something“ because taking the course was Nancy’s idea, a way to prepare for the Caribbean vacation we’d promised ourselves as a break from Boston’s upcoming seven months of winter. Magna cum laude at New England School of Law before becoming an assistant district t attorney, she’d been acing every test we’d had in the course while I’d been getting just about enough questions right to stay alive. I was a little better in the pool than the classroom, though, so I thought I’d probably make it through to the open-water dives all of us would have to complete for certification.
    Caryn had moved off the question to a review of the other laws (Charles’s and Dalton’s) we’d seen, then tied in Henry’s Law on a liquid under pressure absorbing gas proportional to that pressure. Which led to a discussion of the bends and the need to calculate your bottom time (the time you leave the surface until the time you leave the bottom), Caryn stressing the importance of the repetitive dive tables if you go back under before twelve hours have gone by.
    In a whisper, Nancy said, “I think you should be writing this stuff down.“
    I looked at her notebook. It reminded me of a monk copy ing a manuscript. “Nance, if we dive only once a day, we don’t have to worry about the twelve-hour thing, right?“
    A frown.
    Caryn took us through countless examples of multiple dives using the tables. I got hopelessly lost after the third one, so I studied the other students. There was a couple in their fifties, which saved me from being the oldest person in the room. A bunch of yuppies, male and female, who seemed a clique. Two college girls, one a little heavy, the other like an Olympian. Two men who might have been a couple, bud-dying up for the pool exercises but otherwise keeping to themselves.
    Caryn neared the end of our two hours, suggesting we always check to see if a decompression chamber was available on any island we visited. She also recommended not diving shortly before getting on an airplane, which sounded eminently sensible to me.
    “Okay. Any questions on what we’ve covered tonight?“
    The same male student asked another convoluted question about the repetitive dive tables. The two college girls rolled their eyes at each other, then looked toward me and giggled. Caryn noticed, the male student didn’t seem to.
    Nancy leaned over. “Next thing I know, you’ll be passing notes to them.“
    Caryn finished her answer, then said quickly, “Okay, let’s hit the pool.“

    The classroom was in the Boston City Hospital complex. The Center for Adult Education uses the complex because the hospital pool is deep enough to simulate about half an atmosphere of additional pressure. The city morgue’s nearby, but both Nancy and I had been there often enough professionally not to mention it to each other as we split for our respective locker rooms. Everybody reassembled in the pool area wearing just swimsuits and carrying personal mask, fins, and snorkel.
    Caryn was there as well, changed into a sleek, one-piece Speedo. “Okay, how many of you brought knives tonight?“
    Her voice echoed off the tiles in the damp, chlorine-laden air. Five hands went up, two tentatively.
    “Please strap them on, the inside of the calf opposite your major hand. So, if you’re a rightie, strap the knife on the inside of your left calf. That way you can access it if you have to, but it won’t catch your weight belt if you have to ditch the belt during a dive. Remember, always wear the knife in open water, whether diving or just snorkeling. Monofilament fishing line is tough to spot and tougher to snap if you get tangled in it on a reef or a wreck.“
    Hands to her hips. “Okay, don all your equipment - pack, tank, and belt — except for mask and snorkel, and hop in for the drill.“
    The “drill“ the first night of class four weeks ago was swimming three hundred yards without equipment and without stopping. Nancy and I made it, but I was surprised at how demanding it had been and not surprised that six of our original twenty-two students couldn’t do it, being counseled quietly by Caryn that they needed to improve their endurance before maybe registering for the course the next time it was offered. After that first night, the drill built on each thing we learned.
    Caryn said, “Okay,