The stockpot has been a tradition in Western cooking since the days of the Roman Republic and before. Throughout Europe and Russia it yielded up a bounty of soups, stews, vegetable and meat dishes. It crossed the Atlantic with the first American settlers and remained in New World kitchens through the Revolution, through the Civil War, through the westward movement until around World War I, when convenience foods and mass urbanization brought a change to American kitchen practices and eating habits.

Now, with food prives caught in the same inflationary spiral as other consumer goods, with convenience foods costing more and more as labor and production costs skyrocket, many home cooks find themselves looking for easy and appetizing ways to stretch the grocery sollar. The stockpot can supply at least part of the answer. A NEW ENGLAND BOILED BRISKET (Serves 6) 2 1/2 to 3 pound brisket 4 quarts water 4 tablespoons salt 2 bay leaves 10 whole peppercorns 1 tablespoon dried crushed basil 2 cloves garlic 1 large onion 2 carrots 2 ribs celery (with leaves) 4 springs fresh parsley

Trim most of the fat from the brisket and cut vegetables into large pieces; place everything into a large pot. Bring the mixture to a rolling boil over high heat; skim the white foam from the surface as it starts to form and continue skimming until no more rises to the surface. Reduce the heat to low medium and simmer, partially covered for about 2 hours. Remove brisket to a plate, discard vegetables and strain the broth. Wash and rinse the large pot and return the broth and brisket to it.

Then take: 6 carrots, scraped and cut into pieces 3 ribs celery, cut into pieces

6 potatoes, peeled and cut into large pieces 3 turnings, peeled and quartered 8 to 10 whole small onions, peeled 1 large head cabbage, cut into 6 to 8 wedges

Add everything but the cabbage to the pot, cover and simmer over low heat for about 40 minutes (until the vegetables are just tender; add the cabbage for an additional 10 minutes of cooking.

Some people serve the meat and vegetables together in large bowls with the broth, others prefer the vegetables and meat on plates with mugs of broth along side. COCK-A-LEEKIE (Serves 6 to 8) 1/2 pounds prunes 1 1/2 pounds flank steak 3 quarts water 3 tablespoons salt 1 medium fryer, 3 to 3 1/2 pounds 6 leeks (2 left whole, 4 coursely chopped) Freshly ground black pepper

Soak the prunes overnight. Place the flank steak, water and salt into a large pot; bring the water slowly to a boil and skim any foam which appears on the surface; simmer for about 30 minutes. Add the chicken, the two whole leeks and a liberal sprinkling of pepper; again, skim any foam that rises to the surface. Cover and simmer the whole mixture for about 3 hours over very low heat.

Remove the chicken and beef and slice them into boneless portions. Remove and discard the whole leeks. Return the sliced meat to the broth and add the prunes; cover and simmer for 25 minutes; add the chopped leeks and simmer for 5 or 6 minutes more. Serve in large soup bowls with pumpernickel or whole meat bread.

MINESTRONE ALLA MILANESE (Serves 6 to 8)

There are many variations on what Americans have come to know as minestrene; this one comes from the vegetable-rich region around Milan via New York City, Clinton, Ind., and Denver. 1 plump (about 4 pounds) fryer, cut into 4 ot 5 pieces 1 large onion 2 carrots 4 tablespoons salt 1 teaspoon celery salt 1 teaspoon onion salt 1 tablespoon dried basil, crushed 1 rib celery with the leaves 4 quarts water

Cut the vegetables into large pieces, then place all ingredients into a large pot. Bring to a rapid boil over high heat and skim vigorously as the white foam rises, continue skimming until the foam ceases to rise. Reduce the heat to low and simmer, partially covered, for 1 1/2 hours. Remove the chicken to a plate to cool; remove vegetables and discard them; strain the broth. Remove chicken meat from the bones and cut it into medium-size pieces. Wash and rinse the largest pot; return the meat and broth to it.

Then take: 3 carrots scraped and sliced 1 large potato finely diced 1 package (10 1/2 ounces) frozen green beans 1 package (10 1/2 ounces) frozen peas 1 can (12 ounces) whole tomatoes 2 ribs celery, scraped and sliced 1 large onion, finely chopped 1 package (10 1/2 ounces) frozen spinach 2 cups uncooked pasta (shells, noodles, broken linguini or spaghetti)

Test the stock and add more salt if necessary. Add all ingredients except spinach and pasta. Simmer over low heat until the vegetables are barely tender, 25 to 30 minutes. Add spinach and pasta for an additional 15 or 20 minutes, until pasta is aldente. Serve with crusty bread and a green salad.