The greatest substance known to man is something called Life Calk, which smells like New Jersey and looks like road tar.

Life Calk, a product of Life Industries Corp. of Old Bethpage, New York, sticks to just about anything. If you leave it alone long enough it will dry to a medium-hard rubber consistency, creating a waterproof, flexible, airtight sealant.

In the last week I've fixed a shattered watertight boat compartment and a busted taillight on a motorcycle with it, and recommended to one of my bosses that she buy some to reattach her dangling refrigerator gasket. What life puts asunder, Life Calk joins back together.

It comes ina tube and is sold at marine stores worldwide. The thing is, I could kick myself because I'm sure I invented this stuff in 1958, but somebody else is getting the profits.

According to Life Industries president Ed Kehrt, the company is a "small operation with sales in the seven-figure bracket." Seven is where they start counting by the millions.

I'm almost positive that for my science project in the eight grade I made Life Calk, or something very close to it. That year I roped my father into helping me make snythetic rubber from a recipe in the World Book encyclopedia. We didn't have all the exact ingredients so we left out a few and added a few others.

ythe stuff we made consisted largely of sulfur. It smoked and bubbled on the stove for several hours while we were out raking leaves. The smoke coming out the window got so bad that Mrs. Duchnowski next door called the fire department, thinking the kitchen was ablaze.

The end product was a black goo that stuck tenaciously to everything it came in contact with, including the pot, which we had to throw away. It smelled like rotten eggs in a hot, confined place. But Boy, did it stick.

ymr. Melnick the science teacher, was so impressed with the obvious merits of the concoction that he ordered the gasoline can I brought it to school in capped and had a sign drawn up warning other greedy pupils not to open it for anything.

I swore I would never forget the odor and the consistency of that stuff and I didn't. I recognized it the moment I opened my first tube of Life Calk three weeks ago.

When I called Kehrt to determine how he got hold of the precious formula (could the Duchnowskis have sold out?) he at first threw out a bunch of fancy scientific terms but finally admitted, "It is basically synthetic rubber, let's face it."

Life Industries has been producing Life Calk since 1964, when Kerhrt said an entire five-year plan for producing and marketing the product "came to me in a dream. You won't believe it. Nobody does. But that's how it happened."

But his first encounter was polysulfide-based caulking compounds predated that dream by some 20 years, and my fateful encounter at the kitchen stove by a decade.

He was a first lieutenant commanding a gas-generating crew in the Philippines in World War II, Kehrt explained. His men, bored and looking for something to do, discovered 30 abandoned Japanese suicide boats tucked away in hiding.

The boats were 16-foot plywood skiffs with any old auto motor stuck in them. ythe Japanese, Kehrt said, attached an explosive charge to the bow and put a hapless sailor in each with instructions to aim straight for an Allied ship and ram it.

Kerht's crew wanted to use the boats for recreation, presumably after disarming them, but they leaked like sieves from having been too long on land.

Kerht found a polysulfide synthetic rubber concoction that the Air Force was using to patch wings and applied it to the leaky boats. It struck and it worked.

The breakthrough in marketing the stuff for public consumption came a few years later. The original goo needed a catalyst to harden it so it was a two-part mix operation. That's hard to sell. After the war someone figured out how to make a single substance with a catalyst that went into action when it was exposed to moisture.

But it wasn't until 1964 that Kerht had his dream and came up with the idea of marketing the stuff, with refinements for marine use, as Boat Life Life Calk. "Being a boatman anyway, I made my avocation my vocation," he said. The rest is history.

I don't believe in sour grapes, but it does strike me as ironic that Life Calk today is manufactured in Old Bethpage, barely 10 miles away from the place where the frst and only pot of my magnificent coal-black glop came into being.

I certainly donht begrudge Kehrt his success. Anyone who can turn a nightmare into a financial monument is all right in my book.

But I confess to a certain wistful feeling when I realize how close I came to fortune. To think, success was in the palm of my hand. It's not that I let it slip away. I couldn't get the dam stuff off.