It ties in with a Hilton Hotema book I'm reading. He says that our beings are constituted of 4 cosmic principles - earth-air-water-fire and that each is related to one of the first 4 chakras.
chakra 1 - earth - dust of the earth - body of life
chakra 2 - water - river of life
chakra 3 - fire - solar radiation - spark of life
chakra 4 - air - breath of life
For posting the image, I right-clicked on it to save it to my computer and then used Zoebess's instruction which she posted here: