The absolute embodiment of dangerous adult was Long John Silver, who befriended young Jim, purported to be his protector, but was ready to slit his throat without a touch of compunction. Long John was a warning to us kids of what a clever mask evil can construct for itself.

Long John in the book would have made that impression strongly enough; but for me and all kids of my age, it was bolstered hugely by Disney’s film of "Treasure Island." It had a Long John Silver who the very model for all homicidal maniacs. He was played by the brilliant, eccentric Robert Newton, who taught all us boys to squint, leer, and growl, "Ahrrr, matey!"

Newton, who died only four years after making "Treasure Island," had a gift for playing sociopaths. I still shiver at thought of him as Bill Sykes stalking Oliver Twist or as Inspector Javert hounding Jean Valjean or later as Blackbeard the Pirate (really Long John writ large) raging against the world in general.

But the man who first created Long John Silver wasn’t Robert Newton but Robert Louis Stevenson, a Scot whose childhood was steeped in stories of evil masquerading as good. He had been a sickly boy and spent his early years bedridden; he was trapped, he said, "the land of counterpane."

While he rested his "weak lungs," Stevenson was read to steadily by an old nurse who specialized in gory Bible stories and grim accounts of the Calvinist "Covenanters," who had a distinctly dark vision of human nature. That dour nurse, without knowing it, made great contributions to Stevenson’s creation of Silver, a man who rejoiced in wickedness, and of the more complicated, virtuous Dr. Jekyll, who housed a monster within.

Since her charge’s boyhood, that grim old nurse has also given scary thrills to generations of kids through him.

I’m grateful for his work, but I haven’t read much Stevenson since my own boyhood, or thought much about him either. Until recently. What brought him back to mind was, of all things, his own visit to Wick, that stone-built harbor town up in northernmost Scotland. You remember: It’s the place where Anne’s great-great-grandfather prospered in the herring trade and then became a powerful and respected temperance preacher. He inveighed against all alcohol, but with special vehemence, one imagines, against the Pulteney distillery, sited in Wick not a half mile from his temperance chapel.

On our visit to Wick, I passed the chapel on my way to the distillery.

In one of his later essays, Robert Louis Stevenson reminisced about his own early visit to Wick in 1868. He was not yet 20, but, free of his Edinburgh sick bed, he was expending pent-up energy in travels all around Scotland, even into bleak and windy Caithness and "the sub-arctic town of Wick." His descriptions are unflattering, but his prose sings:

"You can never have dwelt in a country more unsightly than that part of Caithness, the land faintly swelling, faintly falling, not a tree, not a hedge row ... the wind always singing in your ears ... As for Wick itself, it is one of the meanest of man’s towns, and situate certainly on the baldest of God’s bays."

But it was not the town, crowded during the herring runs with Gaelic-speaking workers from the Outer Hebrides, that drew the young Stevenson to Wick. From a long line of civil engineers, he was attracted to a major harbor project, a new breakwater to ease the North Sea’s assaults. Divers were working at the breakwater’s tip, placing giant stones underwater to extend it. Stevenson was desperate to experience a dive.

And did. He paid to don the diver’s suit of the day, which had air fed into it from a hand-turned pump on dry land. He had 20 pounds of lead on each foot and was almost bent double when the massive helmet was lowered on his head. "The attendants began to turn the hurdy-gurdy, and the air to whistle through the tube; some one screwed on the barred window of my vizor; and I was cut off in a moment from my fellow-men ... a creature deaf and dumb, pathetically looking forth upon them from a climate of his own."

Down the mossy ladder he struggled, into the dim depths. Fifty rungs down, he stepped onto the harbor bottom and stood in "a green gloaming, somewhat opaque but very restful and delicious." He did some shifting of rock with another diver, then began the slow climb back up the ladder. Almost at the top, "my ascending head passed into the trough of a swell. Out of the green, I shot at once into a glory of rosy, almost sanguine light ... And then the glory faded into the hard, ugly daylight of a Caithness autumn, with a low sky, a gray sea, and a whistling wind." He lumbered back onto the breakwater, back into mundane reality.

Anne and I have both gazed at that massive black breakwater; I got an especially good view trekking to the distillery. It’s odd to think that, long before creating Jim Hawkins, Long John, or Dr. Jekyll, a frail young author (he died at 48) was busy stocking his imagination with real-life adventures.

Far below the waves that we saw crashing against the breakwater, and bearded now in seaweed, crouch a few giant, motionless stones. Robert Louis Stevenson helped set them in place.

Read about Jim Atwell’s book "From Fly Creek _ Celebrating Life in Leatherstocking Country" at JimAtwell.com.