The Phoenicians called. it the Enchanted Isle but the Portuguese named it Madeira after the dense wooden growth they found there in 1420. Measuring a scant 16-by-30 miles, the volcanic island of Madeira pushes up steeply from the ocean bottom to a height of 6,000 feet. From these precipitous slopes came the favorite wine of the American revolution.

But early accounts, Madeira, 400 miles off the coast of Morocco, was so tangled with heavy vegetation tha portuguese sailing captain Joao Goncalves Zarco set fire to the forests, which burned for years. The resulting combination of leaf mold, ash, volcanic soil and tropical sun created the elements for a unique wine.

The original madeira, produced from the malvasia grape from Crete, was sweetish in nature and extremetly popular in Europe as early as the mid-1400s. Much later it was found that madeira shipped to America or India improved after the long, hot journey. The high temperatures and constant rolling of the ships developed the wine into a luscious, supple beverage. The addition of brandy as a stabilizer in the 1700s helped create a demand for madeira shipped "round the Horn and back." Fine madeira graced the tables of America's founding fathers and the courts of Europe's aristocracy. It was wisely acclaimed as a tonic for ailments as well as the ideal perfume for ladies' handkerchiefs.

Then twin disasters struck. The vine disease oidium invaded the island in 1852, followed 20 years later by the equally fatal American root louse, phylloxera. As vines died rapidly, many British firms, known as "lodges" left the island. Only a dedicated few remained. They painstakingly imported and grafted phylloxera-resistant roots to the native grapes. Production fell sharply and the worldwide market for fine madeira never recovered.

Today vines are grown high on over-head trelliswork on the terracted steps of the island and are pruned to allow maximum exposure to the sun. Four grape varieties are cultivated which correspond to the terms used on madeira bottles. In declining degree of sweetness they are malmsey, bual, verdelho and sercial.

The grapes are harvested by hand and taken to presses, which extract the juice, or must. The must is then carried in goatskins to the "estufa", a special building or stove where the wine is heated to 120 degrees during a six-month cycle. This substitutes for the "trip around the Horn".

The wine is then rested for 18 months, sorted and blended by type. The result is a caramel-or butterscotch-flavored wine of varying degrees of sweetness.

Malmsey usually is considered the highest quality product and has a pronounced sweetness, making it an ideal after-dinner drink. Bual retains sweet edge but allows more tartness to show through. Verdelho introduces a light, dry taste but is softer than the completely pale, dry sercial with its powerful nose. Rainwater, a generic blend, is similar to a light verdelho or secial and is produced especially for the American market.

Madeira sometimes is put through the solera system. As with sherry, the solera is designed to marry each successive vintage of madeira into a base consistent with the taste of the original year. Thus an 1860 madeira would be replenished with each year's harvest to compensate for evaporation and current sales. Obviously the bottle may have very little if any original wine but the marriage has taken place to refashion the wine to its original standards.

Occasionally madeira is bottled as a vintage instead of a blend or solera. The date in this case is authentic and such bottles will be rare as well as expensive.

The versatility of madeira is quite remarkable. It is perfect for sauces - not being harmed by the heat as are other wines. It makes an excellent before-dinner drink, the equal of the more familiar dry sherries. And it is a dessert accompaniment comparable to a fine port.

Madiera will last well after exposed to air. Therefore it is one of the only wines suitable for decanter use. If left unopened, your madeira may outlive its owner.And it is not subject to the rigorous conditions recommended for laying down other wines. Just keep it where it is handy.

Though once one of America's most fashionable drinks, today madeira is more often enjoyed in Scandinavia, France and Germany. Recent sales, however, may indicate a resurgence for madeira in this country similar to that developing for port.

Madeira is widely distributed in the Washington area. There are three major lines here, Barbeito, Justino's and Bainchi's with each offering malmsey, bual, sercial, rainwater and the occasional verdelho. The Justino's sercial and rainwater ($3.69 to $4.99) generally are superior while the Bainchi malmsey For bual, the Cossart No. 26 Golden Mellow at Harry's for $4.99 is recommended. The Montgomery County system has a very good sercial in the Leacock Fine Dry madeira at $4.99

Not long ago a number of exceptional solera madeiras were available here. Gradually the supply has dwindled, but with diligence a few still can be found. For those with unlimited budgets, Eagle has a line of vintage madeiras including 1905 sercial, 1934 verdelho, 1914 bual and 1906 malmsey ranging in price from $29 to $48.

Each drop is golden at these prices and you pay as much for the experience as the quality.