The four elements, fire, air, earth, and water, have their own symbols. Air is represented by the circle, fire by the triangle, earth by the square, and water by the crescent - all points on the alchemist's pentacle. You have probably seen one in Rycharde's and Edmonde's lab . Air is moist and hot. Fire, naturally, is hot and dry.
Earth is dry and cold.
And finally, water is cold and moist. In addition, the art of astronomy is quite closely related to alchemy. A very clear example of that are the seven basic metals. Each is governed by its own planetary body. I also have cures and elixirs collected from all over the known world.