Year – Astronomically, the period of time occupied by the earth in making one complete revolution around the sun. The calendar year is an arbitrarily determined division of time, approximating more or less closely the astronomical year. See Calendar, Gregorian (#Gregorian).
Zech, Jacob – Of Prague. Invented the fusee about 1525. The Society of Antiquaries possesses an example of his handiwork – a table time-piece with a circular brass-gilt case 9¾" in diameter and 5" high. For minute description see Archaeologia vol. xxxiii.
Zero – A time-telling term originating or at least made common during the Great War. Word commonly used in a military sense to indicate a secret instant of time from which an attack in its various stages is scheduled.
Zodiac – An imaginary belt 16 degrees in width, spread equally on both sides of the ecliptic (q. v.). It is divided into twelve sections or "signs" which receive their distinguishing names from the twelve principal constellations within the belt. That is how the Babylonians learned to tell the time by looking at the sun and the stars. Only their whole problem was vastly complicated by the daily rotation of the earth on its axis, which of course makes the whole sky seem to turn in the opposite direction day by day. The earth turns in the same direction that it goes round the sun, from West to East. So the heavens turn apparently from East to West, while the annual motion, as we saw just now by the illustration of the clock face, appears in its true direction, Eastward. Also, the great clock of the sky is not from our point of view horizontal, but stood up on edge; and not straight up and down even, but slanted at an angle. So its apparent movements are as it were in several directions at once, and the effect is very confusing. The real motions as they actually do occur are very much simpler and easier to understand. But of these the Babylonians had no idea. They knew only what they could see; and it is all the more wonderful that they contrived to reason out so much and so correctly.
They mapped out a belt or zone around the sky, with the Ecliptic along the middle of it. This they divided into twelve equal parts of thirty degrees each, called Signs or Houses, and each containing a constellation. These constellations were in order, Aries or the Ram; Taurus or the Bull; Gemini or the Twins; Cancer or the Crab; Leo or the Lion; Virgo or the Virgin; Libra or the Scales; Scorpio or the Scorpion; Sagittarius or the Archer; Capricornus or the Goat; Aquarius or the Water-Carrier; and Pisces or the Fishes. We know these by their Latin names, and the whole zone by its Greek name of The Zodiac. But their original titles were much the same, only in a different language. The sun went through one of these constellations each month; and by his position along the Zodiac they told the time of year. Thus the Spring Equinox was where the sun entered the House of the Ram; and that was for the ancients the first day of the new year. The House of the Crab was farthest North, and when the sun got there it was midsummer. The Autumn Equinox was in the House of the Scales; and when the sun reached the House of the Goat, he would be at the Southern or Winter end of his journey. Moreover, since the Moon and the Planets always keep close to the Ecliptic, their apparent motions all lie within the Zodiacal zone. And the Zodiac therefore represented the most important part of the heavens from the standpoint of keeping time; the part, that is, wherein all of those bodies which moved among the stars month by month and day by day appeared to have their motions.