Sun-dials are common in almost all parts of the world, and not a few of them have in one way or another become famous. The largest is at Jaipur in India, and was erected about 1730. Its gnomon is ninety feet high and one hundred and forty-seven feet long. A flight of stone steps run up the slope of it, and at the top there is a sort of little watch-tower. And the shadow, which falls upon a great stone quadrant instead of upon a flat surface, moves at the rate of two and a half inches a minute. Another great dial is the so-called Calendar Stone of Mexico, which was made by the Aztec priests more than a hundred years before the Spaniards came. It weighs nearly fifty tons, and is not only a sun-dial but a representation of the zodiac and a diagram of the astronomical changes of the year: thus showing that the ancient Mexicans in their own way paralleled the astrology of the Babylonians on the other side of the world. Probably the most expensive and elaborate sun-dial ever built was the one set up in 1669 by King Charles II of England in front of the banqueting house at White Hall in London. It was in the form of a tall pyramid on which were two hundred and seventy-one different dials, giving not only the hour of the day but various astronomical and geographical indications as well. The place called Seven Dials in London takes its name from a tall pillar with sun-dials around its top which used to stand at the junction of seven streets radiating starwise from that spot as a center. The pillar was overthrown in 1773 by a party of vandals digging for buried treasure which they believed to have been hidden beneath its base. Extensive list, descriptions and illustrations, See Book of Sun-dials, Mrs. Alfred Gatty; Sun-dials and Roses, Mrs. Alice Morse Earle. [Illustration: OLD ENGLISH PILLAR DIAL] SUN-DIALS, GREEK—1. Diogenes asserts that the first Greek dial or gnomon was erected by Anaximander of Miletus. It was probably a vertical rod on a horizontal plane. This was two centuries after the Dial of Ahaz. 2. On the "Tower of the Winds" in Athens—a dial on each face. SUN-DIAL, HOLLOW—A form of sun-dial invented by the Chaldean Berosus. A hollow hemisphere with a bead at its center, whose shadow indicated the hour of the day. SUN-DIAL, MOTTOES—On nearly all sun-dials both ancient and modern there there is inscribed a motto—usually of the moral significance of the passage of time. Very ancient also, as well as equally common in modern times is the custom of placing upon the sun-dial some appropriate motto expressive of the mystery of Time. There are hundreds of such mottoes, ranging in sentiment from the old Roman one: _Horas non numero nisi Serenas_. "I number no hours but the fair ones," to the couplet of a modern poet: "Time flies, you say? Ah no, Alas! Time stays; we go."