It took going to a cat show in Arlington to find it out, but my own favorite cat celebrity, Chessie, is 50 years old this month.

For readers who might not recognize her, she's the cuddly tabby pictured above, first given nationwide publicity in an advertisement published in the September 1933 issue of Fortune Magazine by the Chesapeake & Ohio Railway to promote the comfort of its new air-conditioned sleeping cars.

Chessie adorned the 1934 calendar issued by the C&O and countless engaging ads through subsequent years, and by the 1960s her name had been adopted as the moniker of the whole railroad--the Chessie System.

An original of the 1935 magazine advertisement in which the reproduced Chessie picture appears cost me $12 at the National Capital Cat Show, held over the weekend at the Thomas Jefferson Center in Arlington. Having been owned by three cats in my adult life, I attended the show with a friend who currently is owned by two Siamese which sometimes adopt me as surrogate.

One of the commercial booths on the sidelines was run by Ken Durham of Washington, who had a selection of cat-related memorabilia, such as cartoons, postcards and authentic Chessie items, including one that tipped me to her hitherto unrecognized half-century birthday. One of the items, a 1956 calendar depicting Chessie being awakened by a Pullman porter as the train arrived at the C&O-owned Greenbriar Hotel resort, was priced at $125.

As we talked, judging was going on at five rings around the huge hall. I dropped by as Donna Jean Thompson of Manassas was judging a dozen Abyssinian kittens. The tiny tawny felines looked, as the young lady alongside me said, "like little mountain lions," but with the deceptively innocent look of kittenhood. Only the apartment restriction that forbids pets kept me from buying and taking one home.