You certainly have been a very prolific writer on your blog and my students and I have been enjoying your posts. I read the post on Float, Sink, Swallow and Spit (September 12, 2006) with interest. I too have heard these terms before in Chinese martial arts, but didn't really delve too deeply to try and find out what they meant. Thanks for relaying the definitions per Harry Cook.
Interestingly enough, we have these concepts in Kishaba Juku, too, although they are not categorized with the same terms. If I get your meanings for each of these: Float equates to rising power as in moving from low block to high block like in Fukyugata Ichi. Sink equates to dropping power or seating the koshi such as we do when we go from high block to low block in Fukyugata Ichi. Swallow sounds like what we refer to as "All blocks suck" or the motion of pulling a blocking or parrying technique back in toward the body. Spit just sounds like what naturally happens after one of the other three. Rising power, dropping power and "blocks suck" are terms that Paris Janos has used over the years that I have trained with him.
When we were in Okinawa, Shinzato Sensei discussed "Floating Koshi" which is a totally different concept from "Float" as described in your post. He described this as a way to press down into your stance, then bounce off the compression in order to change stances or direction quickly by "floating." He demonstrated this by pushing a ball down on the dojo floor, then taking his hand off the compressed ball. This let the ball bounce or float off the floor. We worked on this for a number of hours.
Anyway, keep up the great posts!