Warning - emits sparks

In one of Oscar Wilde's stories, a princess (how could she not have known?) asks the king, ''What are fireworks like?'' The king's answer is typically Wilde and merrily inside-out:

''They are like the Aurora Borealis ... only much more natural. I prefer them to stars myself, as you always know when they are going to appear.''

While His Majesty is doubtless right on the unpredictability of stars, my memory of childhood fireworks suggests he was quite wrong about their reliability.

For some absurd reason the occasion for amateurs to hold firework displays in their back-gardens in England is ''Guy Fawkes Night,'' and this retributive annual effigy-burning of the misguided fellow who tried, whenever-it-was, to blow up the Mother of Parliaments - falls inevitably on the wettest night of the year. It is to this disappointing recurrence that we doubtless owe the dismissive phrase ''a damp squib.'' Our squibs were always damp. You never knew when - or if - they were going to ''appear.'' They soaked up the pervasive moisture like salt, and refused with sullen apathy to respond to countless attempts at activation. And then, just as you gave up on them, they would, with no prompting, go off with a sharp, terrific, crack! I did not like squibs.

And, in truth, I didn't think a great deal more of rockets, though at least they usually headed, with a whoosh, up and away from one. Sometimes, however, the milk bottle they were stood in fell over, and they flew, like mad things, horizontally and crooked, as if in search of an elusive target. More often than not, though, they simply demolished a couple of sleepy begonias in the herbaceous border. At other times they also succumbed to the drizzle and, after a fitful spurt, went out forever with a whimper.

I recall a number of mornings-after-the-Bonfire-Night-before when the grass was littered with the disconsolate and soggy remains of Roman candles that had failed to discharge a single star or colored ball, and various drenched cascades and fountains, asteroids, and comets, now mere carcasses on the deserted battlefield - though they had scarcely put up a fight. What better definition is there of an anticlimax than a firework that has neither fired nor worked?

Sometimes, of course, there were successes, and these made the whole thing worthwhile after all. Hand-held ''sparklers'' generally lit, and excitement mounted as the cold white, crackly fire fizzed and twinkled its way down the wire stem. Even those oversize matches that merely burned with sapphire or ruby flames were thrilling. And Catherine wheels could obligingly whirligig with startling effervescence.

Professional displays outdoing themselves over a half-mile expanse of black sky are infinitely more spectacular than one's meager attempts with a dozen items bought from the local newsagent. But even though the scale is different, the rapture and gasp can be just as spontaneous.

And there is another aspect to home fireworks. The potential factor. I was reminded of it when I happened to glance at a display case in the local museum. There, instantly recognizable, were three old Brock's fireworks, packed with promise and chemistry and decorated in candy colors: a Roman candle, like a stick of seaside peppermint rock, a long tube striped with alternating orange and green spirals; a cone-shaped ''Brock's Continental Erupting Vesuvius'' (it might have contained lemon-sherbet as easily as saltpeter), with a twist of blue touch paper at the peak; but most impressive, the ''Feu de Joie'' (its name, unlike the others, was apparently too splendid for English translation). This substantial drum was not equipped with mere touch paper. It was surmounted by a veritable chimney pot. The casing was cheerful with yellow and red swirls. Its gripping instructions were printed large:

''Firmly bury in soil in an upright position with the case slightly canted away from the spectators ... light touch paper ... stand 30 feet upwind ... Emits sparks, then explodes, throwing stars into the air ... MUST NOT BE HELD.'' And then all round the base of this portentous parcel of pyrotechny there was a procession of W's - WWWWWWWWWWW. (Standing for wild? or wonderful? or what?)

Now that is a firework of fireworks. It calls for planning, a good vocabulary (''canted?''), a knowledge of wind behavior, and a clearheaded gauging of distance. It is a work of art! But who wants it to burn? Its potential is surely quite as marvelous as its performance. I, for one, am glad it has taken up permanent residence in a museum, nice and dry in a glass case, to be gazed at by children and children's children for years to come, its potential never spent.