Later, there was an opportunity to make a greater coup, and here, there was no need for clever expertise. A good eye for beauty was enough. The Madonna and Child painted by Simon Vouet was already admired in the 17th century, as may be inferred from a 1638 engraving that reproduces it. It is one of the French artist’s great masterpieces. The light that falls on the young woman’s face and her adoring yet wistful gaze as she contemplates the infant combine to make it unforgettable. Sold within the estimated bracket, the picture was nevertheless a steal at $158,500. Vouet’s work hardly ever comes up at auction. Indeed, what made the coup possible is the very rarity of his oeuvre, not to be seen anywhere in large numbers. The gem effectively slipped under the radar of most viewers.

Nothing of the kind happened when it came to the two or three outstanding pictures by masters that constantly remain in the public eye.

An exquisite view of a Flemish town under snow painted by Pieter Brueghel the Younger in the late 16th century, The Bird Trap, estimated to be worth $300,000 to $500,000, did better than that as it climbed to $674,500.

A day later Sotheby’s demonstrated the bullishness of the market with a markedly superior sale that took off immediately. A tiny panel by Lorenzo Monaco was the first great catch. The Magus Hermogenes Casting His Magic Books into the Water was originally part of a predella at the base of an altarpiece commissioned in 1387 or 1388. Its boldness appeals to the modern eye, and most of Monaco’s paintings are locked up in churches and museums. Magus Hermogenes climbed to $1.4 million.

The next gem was a profoundly poetic flight into Egypt set in a river landscape, done in the 1620s by the Antwerp master Maerten Ryckaert interpreting an original by Jan Brueghel the Elder. Determined to get it, Johnny Van Haeften, the European leader in Dutch and Flemish art, sent it flying to $698,500, surpassing the high estimate of $500,000.

The ultimate prize of the week was yet to come. The likeness of a Bagpipe Player in Profile, 1624 by Hendrick Ter Brugghen is the kind of major painting by a famous master that normally no longer comes up at auction. This one was returned last year to the heirs of Herbert von Klemperer, an opponent to the Nazi regime, whose painting was dispatched in 1938 to a forced sale. The Sotheby’s estimate, $4 million to $6 million, did not take into account the psychological impact that the unexpected return to the market of a museum rarity has on potential buyers. Van Haeften had told me before the sale that he would try for it, but even he did not expect that he would end up paying $10.2 million, an auction record for the artist.

At that point, the financial tempest raging out in the big world seemed to have been forgotten. A return to reality came with the second big star lot of the evening. The matching likenesses of a Dutch burgher and his wife portrayed by Frans Hals in 1637 are the last such pair by the Haarlem school master still in private hands. But $15 million to $21 million is a gigantic estimate for portraits that lack the rasping edge of Hals at his greatest. These hardly qualified as the kind of opportunity to be pounced upon at any cost, and they crashed unwanted. Other glitches were likewise due to over-optimistic estimation. Salome with the Head of John the Baptist, now considered to be by Titian, is too gruesome, with its matron exhibiting the martyr’s head in a platter, to appeal to many buyers. Nor is it sufficiently established as an undisputed Titian for museums to want it — when last offered at auction, at Christie’s London on December 9, 1994, it was still catalogued as "studio work."

On the whole, though, the sale went well. No truly great picture was ignored. A marvelous, highly original still life with a glass of beer and smoking implements by the little-known and rare 17th-century Amsterdam artist Jan van de Velde thus brought $842,500, and some indifferent works, such as a sentimental Annunciation by Giulio Cesare Procaccini, sold without a hitch. At $362,500, the Procaccini could hardly have fared better. The seemingly ominous casualty rate, 46 percent, merely reflected the difficulty of finding good paintings. Now that the Old Master paintings market has returned to its natural constituency, the connoisseurs, many mediocrities drop dead because nobody wants them, while any misjudgments by the auction-house experts in assessing beauty or quality is fatal.