patterns of flow

"We may say that the earth has a spirit of growth, and that its flesh is the soil; its bones are the successive strata of the rocks...its cartilage is the tufa stone; its blood the veins of its waters."
{that old genius, Leonardo}

I can't find the quote I was looking for-- the one where Leonardo compares water to human hair-- but that one's pretty great, too. I wanted to find it, because I've been trying to study and draw water from direct experience rather than photographs, which have a way of falsifying the elusive stuff (even film and video, which add movement, show a truncated body of information when you're REALLY trying to understand it). I've looked at ways that other artists have drawn water over the centuries before the camera, and it's really beautiful and fascinating. But Leonardo's quote stuck with me because I found it sort of odd. It wasn't until one day I was playing with my younger son's thin baby hair that I realized that hair is like a pre-photographic image of flow that can be studied more slowly than water.