You don't see a thing in this black soup of a night. Nothing. This is frightening. But the soft stacatto cranking of bullfrogs nearby reassures you. You slip slowly into slumber. It has been a long day.

Then, while your mind plays with sweet images, there is a noise that is foreign. You hear it from the deep recesses of unconciousness. A crunching. (Armies marching?) Again you surface into the black night and try to focus on this noise. There. Someone is digging into a paper bag.

Munch, munch, munch.

Good God! Three hours till dawn and some meatball is eating potato chips.

It could only happen in a youth hostel.

The hostel is the Sandy Hook youth hostel in Sandy Hook, Md., a town on the Potomac consisting of a liquor store, a motel and a diner, about two miles from Harpers Ferry, W. Va. The meatball is a hiker off the Applachian Trail (AT), a hiker approaching age 50, from appearances, with crinkly gray hair out to there, a pointed Van Dyke beard in the manner of Kentucky colonels, a toe swollen to the point of bursting and AT patches covering his blue hiking shirt.

He signed into the register as a writer from Maine.

Three other persons are "overnighting" at the hostel, which can accommodate 32. Two are also hikers: one a musician from Massachusetts hiking the trail south; the other a pharmacist from North Carolina walking north. Both are in their 30s, the musician a slow sardonic type, the pharmacist a compulsive story-teller.

Youth hostels? Youth hostels? Yes, the favorite of buck-starved American students in Europe exists in the United States. It is neither a new wave nor a streaking sensation. It's just there, sort of, plugging along. About 225 American hostels in a world-wide network of 5,000.

About 85,000 Americans are AYH (American Youth Hostels) members, enjoying access to hostels both here and abroad. As one of them, you can spend the night in any number of America's favorite recreation areas for as little as $2.50. As long as you're willing to spend it in a bunk-bed with the sounds of occasional munch on a potato chip playing in your ear.

The American hostel movement (insiders like to call it a "movement" in the missionary sense of the word) drew its inspiration in the 1930s from the European example. The first hostel was conceived in Germany in 1909 by an elementary school teacher. By 1930 there were more than 2,000 hostels in that country (about 500 in West Germany today). Americans Isabel and Monroe Smith discovered these on a European trip with students and soon formed AYH.

They opened the first American hostel in 1934 in Northfield, Mass.

Since then, hostel growth has been sporadic and confined largely to New England.

"What we've had," says Robert Johnson, head of hostel development at AYH headquarters in Delaplane, Va., "is fairly slow and steady growth."

A quick scan of the AYH locator map shows many more little black triangles in such states as Massachusetts, New Hampshire, Vermont, New York and Pennsylvania than in any other geographic area of comparable size.

They are spreading, to be sure. Clusters have sprung up in Michigan and Ohio, a bunch in Colorado and California, and others dot the vast westness of the country. Alaska and Hawaii both have hostels (three in Alaska and two in Hawaii).

Many are doing very well, thank you, and, not coincidentally, are in the some of the most preferred places. For just $3.50 you can overnight in the Star of the Sea hostel in Nantucket, Mass. The converted lifeguard statios is listed in the National Register of Historic Places (along with more than 20 other American youth hostels.) The rate at the Martha's Vineyard hostel is $4 a night; $3 at San Pedro, Calif., a few miles from the beach; $2.50 in Port Townsend, Wash., on the coast within walking distance of clamming and the Olympic mountains; $3 at Wailuku on the island of Maui, Hawaii; $2 in Idaho Falls, Idaho, minutes from Yellowstone National Park; and $4 in winter in Kalkaska, Mich., with plenty of ski trails nearby.

(Of course it's not that simple. Many of the better and more appealingly situated hostels require reservations. And prices at the Jackson Hole hostel, in the middle of Teton ski country, are $18 and up.)

Yet, 11 states have no hostels at all. Southern states are the most barren of hostels but other have-nots include North Dakota, Nevada, Utah, and Oklahoma. Another 11 states have but one hostel -- just one in Great Big Texas, for instance.

Hostels come in all shapes and sizes: converted dance halls, restored cabins, private homes and new constructions. About 25 percent are located in urban areas; others are not as conveniently placed as you would like. Some are just plain out-of-the-way. And that is part of the problem with American Youth Hostels. AYH doesn't have the money to build them wherever it pleases (in many cases it relies on charitable organizations to provide buildings at $1 rents).

"It's not a complete chain," says Johnson. "In many ways it's still a bare skeleton of a system."

Cyclists and hikers, for instance, can tour the Potomac River along the C&O Canal towpath from Georgetown to Cumberland, Md. There are two hostels along the way: Sandy Hook and North Branch, near Cumberland. The hostel in Seneca, Md., has been out of operation lately for lack of "houseparents" to run it. AYH expects the hostel to open again soon. But until it does, there's no hostel for the first night out of Washington (unless you can make the 60 miles to Sandy Hook).

Johnson would like to see similar excursion routes -- for walking, biking, rafting, canoeing, etc. -- open up across the country, all outfitted with youth hostels for cheap, engaging overnights.

"The whole idea of a gasless vacation is the thing that we really want to promote," Johnson said.

Some areas where this kind of travel is flourishing, said Johnson, are New England, Pennsylvania, the Airondacks, Michigan, San Francisco Bay, Peugot Sound and around Rocky Mountain National Park.

But many of the nation's major trails and waterways are woefully low on hostels. Fewer than a handful serve the 3,000-mile Transamerica Bicycle trail, only a couple dot the Appalachian trail between Georgia and Maine, and just one or two along the Pacific Crest bicycle path from California to Washington.

Clearly, more work needs to be done getting more hostels, and help may be on the way in the form of legislation introduced in Congress.

U. S. Rep. Richard M. Nolan (D-Minn.) is sponsoring an American Youth Hostels Act that calls for a working relationship between AYH and the Department of the Interior and would provide $9 million in matching grants over three years toward restoration of old buildings for youth hostels. The bill would initiate a national development plan for youth hostels, with cooperation from outdoor recreation organizations, and includes $600,000 in matching grants for new hostel construction where buildings suitable for restoration are unavailable.

The bill must first pass the House National Parks and Insular Affairs subcommittee and the Banking, Finance and Urban Affairs committee. It went nowhere in the subcommittee last year and the committee hasn't touched it yet. But Stan Mahon, legislative assistant to Nolan, said after subcommittee hearings in July that there are indications the bill might reach the House floor this term.

"In the past," said Johnson, "we've relied on enthusiasm, good will and luck. Now we're trying to rely less on luck and plan new hostels. The national plan will explain how we will decide where hostels will go first, based on where the people are, where they go most and where the major national recreation areas are located."

AYH is eager to develop more hostels in transportation centers of major reaction areas as access points to surrounding countryside and wilderness.

"Everyone was enthusiastic for the countryside hostel idea," said Johnson, "but we didn't have the means to funnel people who wanted to go there."

Several major cities, including Washington, D.C., Denver, San Francisco, Seattle, Detroit and Boston, serve popular recreation areas with youth hostel facilities open to American and foreign travelers alike. New York is one of the notable exceptions. Hostelers are directed to the Prince George Hotel. The facility offers discount rates to card holders, but it is not a chartered hostel.

A few hostels are run by the national organization, but AYH normally charters facilities kept by individuals and non-profit groups. Though AYH monitors activities among its chartered members, you can't always depend on the service being the same -- or an good -- from one place to the next. This is reflected in "overnight" statistics.

"There's a real grapevine," says Johnson. "The word goes out about hostels very quickly."

And when the word isn't good -- often because houseparents aren't doing a very good job, Johnson conceded -- people stop going. One Washington area hostel, for instance, consistently reported more than 1,000 overnights annually until 1976. Then the number dropped to 628 and skidded to 600 the next year. A new houseparent was found and overnights immediately went back to more 1,000. He's expecting as many as 1,600 this year.

Beds are provided dormitory style. You can bring your own sleeping bag or sheets.Most hostels offer kitchens, showers, dining areas, sometimes recreation facilities and bike rental, and information on local events and attractions. Rules normally call for lights out around 11 p.m., leaving the hostel in the morning, no alcohol and restricted fraternizing between males and females in the dorm areas (some hostels have more private sleeping quarters for couples and families).

AYH sponsors many trips and will provide, on request, touring information on certain areas of the country, including where to buy maps. Membership is open to individuals of all ages and to groups. Prices are going up this fall to $7 a year for juniors (less than 18) and seniors (more than 65), $14 for everyone else.

Inquiries should be addressed to: American Youth Hostels, Inc., Delaplane, Va. 22025. The AYH handbook, Hosteling USA, lists and describes all U.S. hostels and how to use them.