[136] and each of these, again, received other further subdivisions; for the land was divided into continents and islands, and the water into sea and rivers, and all drinkable springs, and the air was divided into the solstices of summer and winter; fire, also, was divided into what is useful (but fire is a most insatiable and destructive thing), and also by a different division into what is saving; and this division was assigned for the conformation of the heaven.