Having survived 19 office moves, the disappearance of the staff's favorite restaurant, and a subscriber who received 400 copies of the same issue, Smithsonian magazine celebrated its 10th anniversary yesterday -- a mere 2-1/2 months after the event actually occurred.

"There's no particular reason that we picked today," managing editor Don Moser said yesterday as he looked over the layouts of the September issue, which includes a long piece on the fragility of coastal islands, an essay on a Viking artifacts show at the Met, a look at sociobiology and a spread on the great rich who had strange pets.

"We just didn't get around to it in April. We figured anytime in the year would be okay, and April 1 -- when you would have thought the weather would be less predictable . . . UGH!" He wiped sweat from his editorial brow.

Ah, that first 76-page issue. Here's the late Phil Casey writing in these pages about the debut:

"The first issue of 'Smithsonian,' a new magazine published by the Smithsonian Associates, is following a popular trend. It has sex on its cover.

"It's not much as cheesecake though, because the sex is between two elephants. They are courting. And when elephants court, they court. However, this does not show in the photo. It is a picture of the initial stages of an elephant courtship, and it is more tender than provocative; if, indeed, elephants can be either.

"In this photo, the female elephant is making what the handsome, four-color magazine call 'preliminary' advances to a male elephant that insists on keeping on eating banana stalks. Clearly, all is not well, yet. But things apparently improve . . ."

Apparently. Started on an amazingly low budget of $100,000, with a circulation of 175,000, Smithsonian now sells 1.8 million copies a month. It is America's 26th-most-popular magazine, lodged in the publishing statistics right between the 25th-ranked, can't live-without-it V.F.W. magazine and that great chronicler of resistors, Wankel engines and home-built telescopes, Popular Science, No. 27. Last year Smithsonian grossed about $30 million, and -- along with a few other (much less lucrative) Smithsonian Associates programs -- netted $6.4 million for the nation's attic. Not bad for courting elephants.

Some things never change. The current August cover boasts a variation on the courtship ritual, however Oedipal it may be: a common tern, which is a variety of bird, cuddling its new-born chick.

"Our idea in the beginning was to create a magazine that would be interested in whatever the Smithsonian was or might be interested in," said editor and publisher Ed Thompson, choking fitfully on a cigar. Before creating the new monthlky Smithsonian, Thompson spent 30 years at Life magazine, ultimately becoming its editor. At 72, he is taking a leave of absence on Long Island to write a book about the editing process.

"Well, that was a pretty broad mandate. The one thing I told Ripley was that I didn't was to edit a house organ."

Ripley is Secretary of the Smithsonian S. Dillon Ripley, who interrupted his ornithological explorations in India to return to Washington yesterday for the magazine's decennial bash.

"I spent two years trying to fight off the magazine because I thought it would be hideously time-consuming and expensive," said Ripley, who is more used to looking at birds than at magazines. "I was dragged kicking and screaming into it and I have been proven delightfully wrong."

In its decade of existence, Smithsonian has offered its readers a mix of stories on ecology, history, anthropology, technology and art -- a blend of National Geographic, Scientific American, American Heritage, Life and Art News. Subjects have ranged from computers that talk to Japanese carp to the whereabouts of the bones of Christopher Columbus to the world's best private lending library to Post-Impressionist painters.

Even before it began publication, Smithsonian was almost cut off at the pass by an eager cub reporter at a great metropolitan newspaper. The Institution's board of regents had been scheduled to vote on the magazine's fate. One regent, who in fairness shall also go nameless, fell asleep at the meeting. An assistant awakened him with a shot to the ribs -- a mode of revival often called for with this particular public servant -- and the regent shouted, "NO!", his characteristic response to most proposals. Said regent dutifully announced to cub reporter that the magazine in question had been killed, and the ardent member of the press ran with the story, as they say in the newspaper business.

Unfortunately, the matter of Smithsonian magazine hadn't even been discussed at the meeting, and the great metropolitan newspaper printed a retraction.

Once Smithsonian got its bureaucratic green light, it established fledgling advertising offices in a New York hotel whose telephones were destroyed in a fire, forcing ad salesmen to share pay phones with bookies in a tobacconist's shop down the street.

In Washington, meanwhile, the offices were constantly being relocated, often creating awkward situations wherein museum visitors would stroll accidentally into the cubicles of authors laboring over stories.

Editor Ted Park recalled the clever solution of a colleague who posted a sign on his door: TROPICAL DISEASE RESEARCH AUTHORITY Official Visitors Only Please check your special badge for change of color

Park -- who enjoys the rare journalistic distinction of once having thrown 14-year- old Rupert Murdoch out of the newsroom of the Melbourne Herald, owned by Rupert's father, Sir Keith -- recalled fondly editor Thompson's somewhat annoying habit of speaking without removing the cigar from his mouth. This created a mumble that defined mumble. r

"For two weeks running I didn't know whether he had hired me or not because I couldn't understand what he was saying," Park said.

"I think we've done okay with the magazine," mumbled Thompson. "Luckily, when we started up, the magazine fitted well with what was happening in the country -- which was a cultural binge. Somehow we appealed to the right kind of specialized audience. But don't ask me why this magazine worked and Life folded. I've got to write a chapter about that in this book, and I don't know what to write. One goal I had was to edit a magazine that people would read rather than put on a shelf and say, "Some day I've got to read that.'"

Do we detect a slight barb at crosstown National Geographic, to which Smithsonian is often compared (right down to their mutual non-profit status)?

"That's okay," said Bill Garrett, just named editor of the Geographic. When you're No. 3 in circulation -- 10.3 million -- it doesn't hurt much to get poked by No. 26.

"We love 'em. They supplement what we do. The more people that do this, the bigger the pool of money to keep free-lance writers and photographers eating."

And speaking of photographers, how about that great shot of Pittsburgh that Smithsonian ran on its cover: Proofed, run on the presses, stuck in the mail -- and then the letters started pouring in.

Unfortunately, the picture had been reversed.

"If it had been courting elephants, nobody would have noticed," said one staffer. "Pittsburgh, you've got a few people to deal with. . ."