As Americans pause on the Fourth of July to celebrate the bravery of the patriots who created this nation, they might also laud the genius of those who have made the United States what it is today -- and tomorrow. Consider, for instance, Robert M. Green.

Most students of the history of ice cream agree that the moment of greatness for Green, a soft-drink concessionaire at Philadelphia's Franklin Institute Exposition, arrived one day in 1874 when he ran out of sweet cream. This was a time of crisis since Green's featured specialty was the "iced cream soda," made by pouring carbonated water, syrup and sweet cream over shaved ice.

Acting upon his spark of genius, Green substituted melted ice cream for sweet cream.

"The result was satisfactory," the inventor humbly wrote in his diary, "but people were slow to try the new novelty." The first day Green sold only $8 worth of ice-cream sodas, but by the time the exposition closed he was raking in $400 a day on the newfangled drink -- a good example of the power of word-of-mouth.

As it became increasingly stylish to gather around ornate soda fountains during the last quarter of the 19th century, the ice-cream soda became firmly established as an American institution. But the old standard fountain-style drinks, which had become popular decades earlier at the corner drug store, were still much in demand.

It is no accident that the earliest soda-water drinks were sold at drug stores, for they were originally recommended for their medicinal value. When an Englishman named Dr. Joseph Priestly figured out a way to produce carbonic gas in 1767, little did he imagine that 100 years later carbonated waters with added mineral salts would be prescribed as a cure for obesity.

As time went on, dispensers began adding artificially flavored syrups or eggs to make the medicinal drinks more palatable and healthful, and before long America had a range of drinks with such colorful names as phosphates, rickeys, fizzes, flips, toddies, punches, egg creams, frappe's, shakes, malteds and ades. And that infamous character, the soda jerk -- so named for the jerking action of pumping out soda water and syrup -- had become something of a folk hero with a glowing vocabulary entirely his own.

The skill of the soda jerk must not be underestimated, for it took considerable practice to gain familiarity with the hundreds of drink recipes listed in such volumes as the "Modern Guide for Soda Dispensers" (1896) or "The Soda Water Formulary" (1902). Furthermore, the "jerk" was expected to be something of a performer who could "shake, strain, and throw." In the days before the blender, he had to aerate certain drinks by agitating them between a shaker and a glass. He was then expected to "throw" the liquid in an arch through the air from the shaker to the serving glass before it was set before the patron.

Unfortunately, by the mid-1930s America's enthusiasm for the soda fountain began to wane. Many of the younger, talented "jerks" were drafted into the army and by the time they returned, the ice cream soda and lime rickey had begun to play second string to the B.L.T. and the tunafish sandwich. Slowly but surely, the magnificently ornate wood-and-marble soda fountains gave way to the simpler, more streamlined Formica luncheonette counters which dominated during the '50s.

The demise of the soda fountain in America is more than a little sad since many of the wonderful drinks on soda-fountain menus are difficult to reproduce at home. For one thing, the range of syrups commonly available to the soda-fountain dispenser was vast and included such esoteric candidates as crabapple, currant vinegar and wild strawberry. Secondly, the highly carbonated water and the pressure of the pump made it possible to aerate drinks in varying proportions as required.

Nevertheless, some very tasty and refreshing soda-fountain drinks can be prepared either in a blender or -- as in the case of the ice cream soda -- without any machinery at all.

For best results in preparing the following drinks, be sure that all of the ingredients are very cold. The recipes will yield one serving in a 12-ounce glass, and the scoop size is equivalent to 1/4 cup. For a richer drink, substitute whipping cream for the half-and-half and use a very creamy ice cream. For a lighter drink, substitute milk for the half-and-half and experiment with ice milk or sorbet.

Whatever you do, have plenty of straws at the ready! CHOCOLATE SYRUP (Makes 1 1/4 cups)

You may, of course, purchase chocolate syrup, but the following recipe is simple to make and produces a syrup with a slightly more intense flavor than most commercial brands. 3/4 cup unsweetened cocoa powder 3/4 cup sugar 2 teaspoons instant coffee powder Pinch salt

In a small bowl, combine the cocoa powder and sugar. In a heavy saucepan, bring 3/4 cup water to the boil, then reduce to simmer and gradually whisk in the cocoa-sugar mixture. Add the coffee powder and salt, and continue whisking until the mixture is smooth. Cool slightly, then pour into a wide-mouthed jar and cool completely. Store in the refrigerator until needed. BLACK AND WHITE (Chocolate ice-cream soda) (1 serving) 1/3 cup cold half-and-half 2 tablespoons chocolate syrup 3/4 cup no-salt soda water, approximately 2 scoops vanilla ice cream Pour the half-and-half into a tall glass and stir in the chocolate syrup. Add just enough soda water to reach about 2 inches below the rim. Stir to blend. Add ice cream and serve immediately. BROWN COW (Root beer-chocolate float) (1 serving) 1/2 cup cold half-and-half 3 tablespoons chocolate syrup 1/2 cup chilled root beer, approximately 1 to 2 scoops vanilla ice cream

Pour the half-and-half into a tall glass and stir in the chocolate syrup. Add just enough root beer to reach about 2 inches below the rim. Stir vigorously to blend. Add the ice cream and serve immediately with a straw. PASSION FRUIT FRAPPE' (1 serving)

The word frappe' is derived from the French frapper, meaning "to strike". Presumably the reference is to the crushed ice over which syrup and cream were poured to make the traditional frappe'.

The recipe which follows is for a contemporary version of a frappe'. If prognosticators are correct that passion fruit is to become "the kiwi of the '80s," then this drink combines the past and the trendy present in a most agreeable way. 1/4 cup cold half-and-half 6 tablespoons La Grande Passion (a new passion fruit liqueur) 3 ice cubes 2 scoops ( 1/2 cup) vanilla ice cream In a blender capable of chopping ice, combine the above ingredients. Process for about 30 seconds or until the mixture is well blended and frothy. Pour into a tall glass and serve immediately with a straw. MIGNON (Maple syrup ice cream soda) (1 serving) 1/3 cup cold half-and-half 3 tablespoons maple syrup, preferably grade A dark amber* 1/2 cup no-salt, cold soda water, approximately 2 scoops ( 1/2 cup) vanilla ice cream (or substitute maple walnut ice cream)

In a tall glass, combine the half-and-half and the maple syrup. Stir in just enough soda water to reach about 2 inches below the rim. Add the ice cream and serve immediately with a straw.

* If you use a lighter maple syrup which is more delicate in flavor, you may need slightly more. BURN ONE ALL THE WAY (Chocolate malted with chocolate ice cream) (1 serving) Grated nutmeg was the traditional garnish for many soda fountain drinks. Give it a try. 1/2 cup cold half-and-half 2 tablespoons chocolate syrup 1 1/2 tablespoons malted milk powder 3 scoops ( 3/4 cup) chocolate syrup

Freshly grated nutmeg for garnish (optional) In a blender, combine the ingredients and process for about 30 seconds, or until well mixed and frothy. Pour into a tall glass and serve immediately with a straw, garnished with nutmeg if desired.

* If you prefer to omit the malted milk powder, you may combine the other ingredients for a thick chocolate shake. SQUARE MEAL (Chocolate egg cream) (1 serving)

This recipe is a variation of the old-fashioned egg cream, the one that still had the egg in it. 1 egg 1/2 cup cold half-and-half 3 tablespoons chocolate syrup 2 scoops ( 1/2 cup) chocolate ice cream In a blender, combine the ingredients and process for about 30 seconds, or until well mixed and frothy. Pour into a tall glass and serve immediately with a straw. STRAWBERRY THICK SHAKE (1 serving) 1 cup cold fresh strawberries (about 10 large) 1/2 cup cold half-and-half 2 scoops ( 1/2 cup) vanilla or strawberry ice cream Confectioners' sugar to taste, if needed In a blender, pure'e strawberries with the half-and-half. Blend in the ice cream. Taste and add sugar, if needed. Continue to process for another 20 to 30 seconds, or until mixture is well blended and frothy. Pour into a tall glass and serve immediately with a straw.