MOSCOW: Through a long succession of sick days, Boris Yeltsin has definitely retained his sense of timing. Kremlin officials happily announced today that not only was the Russian president back in the Kremlin, but that Yeltsin would indeed keep this weekend's meeting with French President Jacques Chirac in Moscow. Yeltsin, who turns 66 on Saturday, returned to work in Moscow for the first time since Jan. 18, ostensibly to meet with Prime Minister Viktor Chernomyrdin and review government documents. But in what has become a symbolic gesture of declining value, the president's real purpose was to prove that he is able to show up at work. Aides aroused new suspicions about his health problems Monday, when they canceled Yeltsin's planned Feb. 4 trip to the Netherlands to consult with EU leaders. His March summit with President Clinton had already been postponed, and now are placing increased emphasis on a meeting next month between fellow heartbeat-aways Chernomyrdin and Al Gore.