09:1 · The cross with arms of equal length is an extremely old ideogram used in most cultures. It is also one of the basic gestalts in Western ideography (as opposed to the basic elements, which are derived entities). The cross is found in every part of the world, in prehistoric caves and engraved on rocks.
    In pre-Columbian America the sign seems to have been associated to the four points of the compass and the weather gods. In the earliest Chinese ideography it appears as a sign for perfection and 10, the most perfect number. In astrological symbolism is the graphic symbol for matter, the earthly life, the plane of physical existence.
    Compare this with , which in early Chinese ideography meant ground.
    The alchemists used as one of the signs for the four elements represented by the four arms. Their point of intersection they perceived as coniunctio, quinta essentia, the fifth element, etc. But the cross was much more often used as a sign for acids, vinegar and soot by the alchemists and early chemists.
    The alchemists of the Middle Ages also used to append a cross to most of their signs for chemical elements and compounds.
    Semiotically the stem of the cross, the vertical beam (see in Group 10) stands for the heavenly or spiritual, whereas the transverse beam (see in Group 10) represents the material plane of existence.
    The cross as a closed sign, and with arms of equal length, , and the Latin cross, , are the ideograms most closely associated with the Western world and thus also appear on many Western countries' flags.
    The cross with arms of equal length was common in the neolithic age. The so called Ice Man, a man who died on the top of an Alp pass at 3000 meters about 3200 B.C., had this sign tattooed on one of his legs. Read about him and his death in Der Mann im Eis, 1993, by prof. Konrad Spindler.
    Many of the first cross structures were those of the wheel cross, which was used in e.g. Assyria () and ancient Egypt (). In Assyria, at least, it clearly is a symbol for the sun. On the other hand it also is a graphic representation of the centralizing revolution of the ancient societies' social structure that was associated with the invention of the wheel, as the meaning town of the Egyptian hieroglyph just showed suggests. The great semiotician Marshall McLuhan wrote that all media and inventions are extensions of some basic human faculty. The wheel, as an extension of the foot, was a powerful centralizing force. By foot you can walk in faraway places where a cart would have great difficulties in getting through. But near the center of a society the swamps become fields, and the paths become roads. Thus transport successively becomes more easy the closer you get to the center of a human society. It is easy to get to the center, but gradually more difficult to travel and transport the longer from the center you get. That is the rationale behind McLuhan's words about the centralizing effects of the invention of the wheel.
    For more data about the cross and its history as an ideogram, see in Group 3. In Western ideography the cross, and its graphic opposite, the circle, are the most common basic gestalts, and appear in many different Western ideographic systems. Here are some of the meanings of in different systems: death, end and beginning (on coins and medals with reference to inscriptions), boundary (rows of crosses on maps), shoal (maps and nautical charts), church, chapel (maps, charts), north (astronomy), positive pole or terminal or charge (electricity), clockwise rotation (optics), and positive ions (chemistry).
    In dualistic systems of signs represents the positive pole: positive charge, increase, and the hemisphere north of the equator.
    In the sixteenth century began to be used in mathematics, and we know it as the plus sign meaning addition.
    The law of the polarity of meanings of elementary graphs is well illustrated by , which is both a sign that unites, as in logic, mathematics, and chemistry, and a sign that separates, as in numismatics and cartography; and is positive in many systems, but negative in the French hobo or gypsy system: here they give nothing.
    For as a Christian symbol, see in Group 3, and "The sign of the cross in Western ideography" in the Appendices.