A reader called to say you can no longer buy a one pound can of coffee in America. Everything, she insisted, is now 13 ounces.

I went to the store and found she was right. First we lose the 8 ounce candy bar, then the one pound can of coffee, soon a gallon of milk will be down to 3 1/2 quarts.I decided it was time for some investigative journalism. I began by calling Melitta USA. The woman who answered transferred me to public relations. Public relations got nervous and transferred me to customer service. In turn, customer service transferred me to marketing. A woman there asked what she could do for me. I told her what I wanted.

"There's nobody here to answer," she said. "They're all at conferences."

Obviously, hiding from the truth.

I moved on to the next company on my list - Chock Full O' Nuts. They've now cut their cans down to a mere 10.5 ounces. I prepared some hard hitting questions to make them answer for this. Then I called directory assitance. Chock Full O' Nuts, it turns out, has an unpublished number. I guess I'd be unpublished too if I was selling a pound of coffee in 10.5 ounce servings.

Next, I called Autocrat, which is down to 14 ounces. I asked what had happened to the pound version.

"It's gone," said a woman in customer service.

"Gone?

"Gone," she said. Then she tried to wriggle out of it. "We stayed with a 14 so we're still higher than everyone - especially Folger's - watch out, they're 11.5."

But she couldn't say why. So I decided to switch strategies and call Martinson coffee, the one brand I could find that still sells a full pound.

A receptionist answered. I told her my business.

"Will there be a story written about us?" she said.

I told her there would be.

"I'll ring you up to Mr. Lincoln in legal," she said.

Mr. Lincoln wasn't in so they sent me to an associate product manager, who insisted Martinson was committed to the integrity of the one pound can.

I asked about the future.

"That decision is I suppose subject to business trends," I was told. "If all the dinosaurs become extinct and you're a dinosaur . . ." The associate product manager let the sentence linger.

I still didn't have my explanation. So I tried Hills Brothers, another 13 ounce convert. It turns out they're owned by Nestle, a Swiss company. It made sense that this was part of a foreign conspiracy. I asked what happened to the one pound can of coffee.

"They cut it down to size," a Hills Brothers spokeswoman said guiltily, "didn't they?"

I asked her why. She tried to dodge.

"Well," she said, "it's an industry wide movement."

Then she gave me a lead. She suggested I call Maxwell House or Folger's.

I did call Folger's.

"Thank you for calling Proctor and Gamble," said a Folgers recording.

Proctor and Gamble? So that was it. Michael Milken had no doubt helped P&G engineer a hostile takeover of Folgers, which in turn was forced to cut pound cans of coffee to 13 ounces to pay off the debt. Soon, I was transferred to the company's consumer answer line. I got a woman named Joan. I have to give Proctor and Gamble credit; they sure have their lines down.

"Basically," explained Joan, "Folgers has developed a fast roast method that yields more from each bean. The grounds are more porous like gravel instead of more dense like sand, allowing more water to come in contact with the surfaces."

In other words, a new process puffs up the bean, giving it more surface, so when water hits it it yields more coffee. Thirteen ounces allegedly gives you the same bang that 16 used to.

At least that's what the coffee industry tells us.

Get ready for the 3 1/2 quart gallon of milk.