The Ancient Art of Incubation                                                                      We know that the domestication of fowl began about 6000 years ago. The first records of crude incubation for hatching eggs is documented in Alexandria, but we get a better example and understanding when we study the methods of the ancient Egyptian civilization. Fowl have been observed in their natural habitats building nests to incubate their young. Writings from Greek mythology show us that man was observant concerning his surroundings and the hen since about 400 B.C. Aristotle, " The bird eggs and eggs of the fore footed beasts are ripened by the Incubation of the dam." It was the observance of the hen and natural incubation that led man to try artificial means of hatching. "For all these lay in the earth, and their eggs are hatched by the warmth of the Earth." Upon these observations of the hen and her nest man began to attempt to simulate what he observed. Ancient cultures were aware of the radiant heat that the hen created upon setting and thus found natural means to recreate that heat. One such way to generate the heat needed to hatch is the using of animal "dung". Many ancient cultures used mounds of animal dung to incubate larger amounts of eggs. In the same manner as an undomesticated hen they would fashion a hole in the earth, where upon they would pile a mound of eggs and cover with dung. The ancient Chinese were the first to use animal dung for fuel to generate heat for incubation. This method of artificial incubation would lead to the building of small buildings or rooms for incubation. Eggs would be placed taking care in placement as we learn by the writings of John Baptist Porta, "Lay upon every story a hundred eggs more or less.  Let the great end of the eggs, lie downwards, the sharp end upwards."   Eggs were placed in large piles on the floor in carefully constructed rooms with an upper and lower chamber. In the upper chamber of the room shelves would be constructed with low burning fires of dung, straw, or charcoal. The ancients understood the theory of radiant heat needed in order to incubate and hatch. It is also a belief that they may have understood the need for sufficient oxygen levels and heat radiating from developing eggs. Could this understanding have influenced the architecture of the incubation rooms they built. A struggle that many will have to deal with in the development of incubators along the way. Depending upon the design some would only allow entry of an arm for the ritual of turning the eggs, later designs allowing complete entrance through small manholes, to eventually rooms and accommodations that could be a residence for those that cared for the eggs. John Baptist Porta traveled great distances and wrote of what he saw. He was considered a naturalist, and one of the most famous writers and scientist in Italy at the time, and viewed these natural occurrences as magic in the 1500’s. From his writings we are able to ascertain that many cultures were beginning to use the art of radiant heat. He explains in great detail what must be done in order to hatch without the use of a hen. He also writes how he observed these cultures monitoring heat, fertility and when a hatch should occur. " Take an egg out of the place, and lay it on your eye, for that will try it well.  If is too hot for you, the heat is too much.  If you feel it not, it is weak.  A strong heat will hatch them, but a weak one will make them addle. So you must add or take away from your lamp, to make the light adequate and proportional.  After the fourth day that the Eggs begin to be warmed, take them out of the cells, and not shaking them hard, hold them gently against the Sun beams or light of a candle, and see whether they be not Addle.  For if you discern any fibers or bloody matter run about the Egg, it is good.  But if it is clear and transparent, it is naught.  Put another Egg in place of it.  All that are good must be daily turned at the lamp heat, and turn them round as the Hen is found to do." In another passage we see his relating what he must have observed upon the time for hatching, " In summer after nineteen or twenty days, or in winter after twenty-five or twenty-eight days, you shall take the Eggs in your hand, and hold them against the Sun and see how the Chicken beak stands.  There break the shell, and by the hole of the Egg take the Chicken by the beak and pull out its head.  And lay it in its place again.  For the Chicken will come forth itself. " A key point that Porta observed, was hatching regardless of the season, this will many centuries later influence and encourage the design of artificial incubators.