If you were wondering why Martin Scorsese decided to adapt Brian Selznick's children's book 'The Invention of Hugo Cabret,' consider this: at one point in the film, a bearded film historian (Michael Stuhlbarg, looking like Scorsese circa 'After Hours') makes a plea for preserving old movies and why its important to remember where the medium came from. Which is another way of saying that 'Hugo' may be the first children's film for Cahiers du Cinéma subscribers. Scorsese screened a work-in-progress cut of 'Hugo' at the New York Film Festival on Monday night (the surprise screening was spoiled earlier Monday by the scoopsters at Deadline) in front of journalists, fans, and Selznick himself, who was seated near me with what seemed like his entire family. They were very pleased with the unfinished 3D film. So were many of the theatergoers, judging from the laughter, applause and general post-screening reaction. Ahead, seven observations from inside New York's Avery Fisher Hall about the first public screening of 'Hugo.'