First, the president blew the whistle.

Then the circus began.

And then 17 elephants stood in a row, waiting for their marching orders.

No, it wasn't the start of another session of Congress, or a party line vote on the MX missile, but a morning of mirth and merriment for Ronald Reagan, who joined thousands of children at the Ringling Bros. and Barnum & Bailey Circus yesterday at the D.C. Armory.

"You know, this year is the Ringling Brothers' 100th birthday," the president quipped. "They're just a little older than I am."

Between the hordes of Secret Service agents and the platoon of photographers and reporters, the kids who made up the crowd ended up getting two circuses for the price of one. The president had arrived and made his entrance under a banner that read "Welcome Mr. President to the Greatest Show on Earth" (which turns out not to be "Nightline" after all). The children were duly impressed, briefly, as is their nature.

The president made an appearance at the circus not just to get away from some of it, but to introduce the Safe Kids program developed by the circus in response to the epidemic of missing children -- nationwide, 1.8 million children under 18 are currently classified as missing. Safe Kids will provide intensive safety education programs in more than 85 cities where Ringling Bros. and Barnum & Bailey's two traveling circuses have their runs. The program will also provide identification documents for parents that will include a child's color photograph, fingerprints and other pertinent information.

Reagan praised the circus-initiated program as one remedy for "all the problems that we're having in this country with missing children . They're going to give children and parents an opportunity to obtain free educational material and identification documentation and help keep your families safe and secure."

The president talked about a national partnership between businesses and government for child safety and then suggested several steps children should follow, including memorizing their full home addresses and telephone numbers, learning how to dial a phone and always letting their parents know where they are. "And most important, listen carefully to all the special safety tips that your parents and your teachers tell you. Each and every one of you is very important to us."

Before Reagan arrived, seven students from Martin Luther King Jr. Elementary School, which just happens to be the president's "adopted" school, were being fingerprinted by D.C. police officer C.M. Lee. Helping out was a clown who assured 7-year-old Armasherri Smith that her prints were "pretty." Also fingerprinted was the president's Official Pen Pal, second-grader Rudolph Hines.

After the president vigorously blew his Official Ringmaster's Whistle, he settled in among the 500 students from the King school and enjoyed a slightly truncated first half of the circus. Reagan seemed absorbed by the airborne adventures of the auspiciously accomplished aerial artists as they amply achieved astonishing acmes of altitudinous adeptness.

Not cut were two typically glitzy production numbers, the second of which was filled with the kind of patriotic fervor and imagery -- colorful eagle-emblazoned covers draping those reassuring elephants -- that the president seems to inspire.