IF YOU'RE planning to send your sweetie a valentine, you should know that in the old days Feb. 14 was a holiday mostly for high rollers. The reason was the high cost of postage, thanks to a Congress sitting in Washington that was allergic to red ink.

In the early 19th century, for example, mailing costs were determined by distance. A letter moving 39 miles would cost 6 cents, but one in excess of 400 miles would cost 25 cents. Valentines traveling long distances thus represented sizable investments.

It took Congress until 1851 to recognize high postal rates were bad public policy. In that year, it threw out rates based on distance and substituted a 3-cent first-class stamp. The effect on Valentine Day's missives was enormous, especially as commercial printers produced cards for as little as a penny. By 1863, one periodical noted that "with the exception of Christmas there is no festival throughout the year which is invested with half the interest belonging to this cherished {Feb. 14} anniversary."

Of course, certain towns with names of endearment over subsequent years tried to get lovers to send valentines from their post offices. These included Loveland, Colo.; Romance, Ark.; Darling, Pa.; and Kissimmee, Fla. Other towns or cities without loving names tried to promote contests for the best original verse for the day, and still others awarded prizes for partial poems, such as the final two lines of the traditional Valentine Day's verse that begins "Roses are red, violets are blue . . . ."

Other Americans with a fascination for trivia remember Feb. 14 in terms of the best, worst or unique things that happened on that day.

The best events of Feb. 14:

Oregon (1859) and Arizona (1912) became states.

Comedian Jack Benny was born in 1894, retaining until his death the loving age of 39.

Captain Cook went the way of the wind in Hawaii in 1779.

A solar eclipse occurred in 1934, making the day all the more intriguing for lovers.

The worst events:

The gangland massacre in Chicago in 1929.

The closing of all Michigan banks in 1933 during the depth of the Great Depression.

The launching of the German warship Bismarck in 1939.

The most disputed event of Feb. 14 occurred in 1876. Elisha Gray and Alexander Graham Bell both filed their patents for the telephone on Valentine's Day of that year, but Bell beat Gray by just a few hours.

The most popular valentine of World War I was when Herbert Hoover held the position of food administrator, admonishing Americans to eat less butter on their spuds and to observe wheatless and meatless times in order to ensure adequate food resources at home and abroad. The most popular verse on Feb. 14, 1918, read:

I can Hooverize on dinners,

And on lights and fuel, too,

But I'll never learn to Hooverize

When it comes to loving you.

Thomas V. DiBacco is a historian at American University.