As you untangle that holiday knot of colored bulbs and green wire that spends 50 weeks a year in a box with brown evergreen needles, you might do it with a little reverence, for this Christmas marks the 100th anniversary of the first electric Christmas-tree lights.

In 1882 Christmas lights were candles, sometimes clipped to tree branches, until Edward Johnson, a vice-president of Edison's Electric Company, had a string of 88 hand-blown bulbs, each the size of a walnut, strung together on the Christmas tree in his home on 36th Street in New York.

That first tree had red, white and blue bulbs and was rotated slowly by an electric motor in the base.

Soon, Christmas lights became a fad -- but only among the very rich. Bulbs cost one dollar each and had to be wired together by a "wireman." J. P. Morgan had a generator to power his tree since he lived outside the electrified part of New York City.

In 1890 General Electric, which had bought Edison's rights and factory, began to sell more bulbs as well as to rent them out during the holiday season.

At the turn of the century, Ever-Ready Company began marketing "festoons," strings of 28 bulb sockets. Later, they sold festoons that could be joined together for longer chains. Early advertisements extolled the safety of electric lights over open candles, which had started many tragic Yuletide fires.

By World War I, Christmas lights still remained beyond the reach of the average worker. But the affluent bestowed lights on the poor in the form of public displays. The first such display, the "People's Christmas Tree," erected in 1912 in New York, was decorated with lights donated by wealthy families.

Most New Yorkers, seeing Christmas lights for the first time, regarded them as a shining example of American inventiveness, the mystical joining of a wondrous new technology with an emotional, religious holiday. Those flameless colored lights, powered by unseen energy coursing through thin wires, were seen as miracles of the age.

American City Magazine wrote that the tree was "tender altruism," "publicity for a throbbing thought of love and kindness" but warned, "let us keep our tree free from the material misinterpretation of Christmas."

Two years later, 600 cities had "Trees of Lights," powered by electricity. Philadelphia had one with 400 bulbs. After World War I, the "tender altruism" of the earlier trees began to fade. Municipalities realized that public display of watts and wonder was good advertising for commercial areas. As one city official said, "Christmas lighting of the streets opens the pocket as well as the heart."

By the 1920s towns had not just one lit tree, but long rows of them. Inevitably, these "whiteways" were located in business districts.

Meanwhile, Christmas lights became cheaper to buy for the home. Underwriters Laboratory first set safety standards for them in 1921 and soon after, GE introduced outdoor lamps. Parallel wiring, bubbler lamps, twinklers and miniatures were to follow.

Now, as then, Christmas lights define the season with their high visibility and dazzle. They are appropriate symbols for this time of year, when light returns to the earth and longer days begin, promising warmth to come.