Just when art world observers were beginning to fret about a suddenly lukewarm auction market, Mark Rothko’s work once again sold for a dizzying figure. The painter’s “No. 1 (Royal Red and Blue)” went to a telephone buyer at Sotheby’s last night for $75.1 million–including the house’s fees. The classic 1954 canvas is a prominent example of what art enthusiasts call “wall power,” and continues the tradition of Rothko artworks setting the auction world on fire. In 2007 David Rockefeller sold a 1950 abstract canvas by the artist for $72.8 million, and in May Sotheby’s sold “Orange, Red, Yellow,” from 1961, for almost $87 million.