Bill Hanna - "Saturday Evening Puss"

This scene below from "Saturday Evening Puss" is one of my favorite musical moments from Tom and Jerry. I think Bill Hanna had a great sense of timing, and not just for musical numbers. Though I do think he was greatly influenced by those he worked with. Early in his career as director the timing of his cartoons is very similar to a Rudy Ising short. When Tex Avery started at MGM Hanna-Barbera's cartoons really started to pick up the pace much like Tex's shorts. Here's a couple of paragraphs from Bill Hanna's biography on timing:

Timing a cartoon is a partly mathematical and partly intuitive process. In studying the markings indicated on the metronome, I was able to determine that when the metronome clicked at a rate of 144 beats per minute, every beat represented ten frames of film. Using the index of twenty-four frames a second in animation movement, I figured that a twelve beat was half of that, so every time it clicked it would be twelve frames. Using that multiple I marked on my metronome for a ten beat, twelve beat, fourteen beat, sixteen beat, and so on to setting the tempo of, for example, a character’s walk by coordinating the action in frames to the beat of the metronome.

Such an axiom was fine for some things. In others, such as timing the facial reaction of a character, a double take, or some other comedic or dramatic bit of action, you just had to rely on your intuitive sense of timing and know how long you wanted to hold that look on their face, or other bit of business the action calls for. Then it becomes something that is felt more than precisely measured. You see it, you feel it, and somehow you just know if it is right or wrong.