The proverbially cool cucumber, perfect in salads and soups

In the Dickens novel ''Martin Chuzzlewit'' Sairey Gamp says, ''In case there should be such a thing as a cowcumber in the house will you be so kind as to bring it, for I'm rather partial to 'em.''

The word and its pronunciation may have changed but not the world's liking for cucumbers. In this country, only tomatoes and beans are more popular in the backyard plot.

There is a logical reason for the phrase ''cool as a cucumber.'' The pulp temperature of a cucumber is 20 degrees cooler than the outside air.

Therefore, it is not surprising that it is used more in salads and in cold soups than in any other manner.

The crispness is also a great boon to sandwiches, either plain or in combination with egg salad, cold sliced meats, and in seafood or poultry salads and many other dishes.

Broadly classified, there are three types of cucumbers, although there are many varieties. Some have white skins; yellow ones are called lemon cukes. But most have dark green shiny skins.

A small variety, the gherkin, is used for pickling in vinegar and the small green French cucumber, most always served with pate is called a cornichon.

A new, long, variety, either European or Oriental is now in most supermarkets. It has a long slender shape, and is pointed at both ends.

This is the type I enjoyed while visiting Turkey. They are sold by street vendors who carry salt shakers with them for seasoning the raw vegetable.

Cucumbers were somewhat neglected in cookbooks of the past, although they were often pared, sliced, soaked in salt water and wrung out until the pulp was soft and limp. We now know that fresh garden cucumbers add crunch and color to a salad if the skin is left on. If skins are tough or bitter, or waxed, they should of course be peeled.

To seed a cucumber, halve it lengthwise and scoop out the seeds with a teaspoon. If it is to be stuffed, seed it with an apple corer.

Elegant restaurants often cut the peeled, seeded cucumber into ovals about an inch long, simmer in chicken broth or steam them and serve as a vegetable.

Anywhere in the world where cucumbers are grown you will find favorite regional recipes such as the Greek Tsatziki, which is cucumbers in yogurt and garlic sauce.

In New England there was a time when a serving dish of marinated cucumbers was a fixture on the summer table. Marinated Cucumber Slices 2 small or 1 large cucumber, unpeeled, seeded and very thinly sliced 1 1/2 teaspoons salt 1/2 cup white vinegar 1/4 cup finely chopped parsley 1/2 teaspoon sugar 1/4 teaspoon white pepper

Layer cucumber slices with 1 teaspoon of salt in a 9-inch pie plate. Let stand 10 minutes. Press cucumbers into plate and pour off liquid that accumulates.

Sprinkle vinegar, parsley, sugar, pepper, and remaining salt over cucumbers, tossing gently to mix well. Marinate, covered, for at least 30 minutes to let flavors blend before serving. Serves 6.

We are all familiar with the delicious cold summer cucumber soups made with sour cream or yogurt. The following is a hot variation, Finnish in origin. Hot Cucumber Soup 4 5-inch cucumbers, peeled, seeded, and sliced 1 small onion, chopped 2 tablespoons butter of margarine 3 tablespoons flour 6 cups chicken broth 1/4 teaspoon white pepper Salt to taste 1 cup half-and-half 2 egg yolks 3 tablespoons chopped parsley Chopped cucumber for garnish

Simmer cucumbers and onion in butter in Dutch oven 10 minutes, being careful not to brown. Sprinkle with flour and stir until blended. Gradually stir in broth and pepper and simmer 10 minutes.

Press through strainer or food mill or whirl mixture, 1 cup at a time, in blender. Salt to taste. Blend half-and-half and egg yolks. Add to puree and heat , but don't boil. Sprinkle with parsley and serve at once. Pass chopped cucumber. Serves 6 to 8.