Dec. 13, Monday -- St. Lucy. Stolen "Mona Lisa" returned to Louvre, 1913. Mary Todd Lincoln born, 1818.

Dec. 14, Tuesday -- Halcyon Days. Nostradamus born, 1503. Washington died, 1799.Dec. 15, Wednesday -- Ember Day. Bill of Rights Day. Sitting Bull died, 1890.

Dec. 16, Thursday -- Margaret Mead born, 1901. Boston Tea Party, 1773.

Dec. 17, Friday -- Ember Day. Arthur Fiedler born, 1896. Moon on Equator.

Dec. 18, Saturday -- Ember Day. "Each day that Fortune gives you, be it what it may, set down for gain." -- Horace.

Dec. 19, Sunday -- Fourth Sunday in Advent. "Piercing cold" at Valley Forge, 1777.

Ask the Old Farmer's Almanac: What is the source of "Yule" as in Yuletide and Yule logs? -- B.U., New York, N.Y.

Answer:It comes from the feast of Jul, a Scandinavian celebration in honor of Thor, then passed down through the Goths and Saxons. In Sweden, St. Lucy's Day (Dec. 13) coincided with Little Yule Day and signaled the beginning of the Midwinter Festival. Originally a solar ritual, celebrated around the time of the Winter Solstice, Jul or Yuletide festivities included fires to symbolize the heat of the Sun and inviting the renewal of light. Yule logs were as big and hard as possible, for longer burning. In some cases, they were actually a large ball of roots. They might be burned one night, then carefully smothered with ashes and stoked again the following nights, for as long as possible. In some customs, a branch of the Yule log would be saved from one year and used to light the Yule log of the following year. Ashes from the consumed Yule log might be strewn over the fields, to encourage better fertility of crops.

Various hearth rituals have been added to the Yule ceremony, over the years. In the American South in the 1800s, the Yule custom was briefly associated with certain slavery laws. Slave owners might be bound by laws that afforded the slaves seven days rest around this holiday. In some localities, this was equated with the time it took the Yule log to burn, which led to some clever ways to prolong the Yule burning -- such as by soaking the log in water.

In some cultures, prayers or hymns might be offered up the chimney, in hopes of a better reception. Sweeping and cleaning the hearth, decorating it with evergreens (home to the good-willed forest fairies and spirits), and later, waiting for Santa Claus are just a few of the rituals that have merged from various cultures.

Ask the Old Farmer's Almanac: Somewhere, I've seen the math that goes with the Christmas carol, "The Twelve Days of Christmas." Can you supply it? -- M.K., Marblehead, Mass.

Answer: In calculating carols, be sure to have an extra adding machine tape at hand. Here's the addition of what "my true love sends to me," adding up the total after each round of the song is sung: 12 partridges in 12 pear trees, 42 swans a-swimming, 22 turtle doves, 40 maids a-milking, plus cows, of course; 30 French hens, 36 ladies dancing, 36 calling birds, 30 lords a-leaping, 40 gold rings, 22 pipers piping, 42 geese a-laying (no eggs yet, that we know of... ) and 12 drummers drumming.

We've also seen attempts to estimate what the total gift might cost, in today's numbers, but we'll leave that part to you. In some cases, supplies may be difficult to find. We suggest you shop early.

Ask the Old Farmer's Almanac: Does the evergreen tree that housebuilders nail to the rafters for good luck have Christmas associations? -- T. A., Beaumont, Texas

Answer: Not particularly, no, although the evergreen itself is a symbol of renewal or immortality, in both cases. Once the roof rafters are raised on a new dwelling, the custom is to nail an evergreen tree to the highest peak to appease the wood gods and bring good luck to the house. There are many superstitions associated with wood, most of which come from early pagan rituals and druid rites.

For example, trees are considered the homes of the gods, so touching bare wood brings their favorable luck. You've probably heard of knocking on wood when you ask a favor, speak of good luck, or boast of accomplishment.

Knocking three times is even better. Poplar is considered the devil's wood, the proof being that its leaves never stand still whether the wind blows or not. Some lumberjacks won't cut it, because it's believed to be the wood of Christ's crucifix.

As for the coming holiday, it's bad luck to bring cedar boughs or mistletoe into the house except around Christmas. So, now's the time.

Send your questions to: Ask the Almanac, The Old Farmer's Almanac, Main St., Dublin, NH 03444. Every day the editors of The Old Farmer's Almanac answer a question on the Internet. All questions are archived there as well. On the World Wide Web, the address is www.almanac.comYankee Publishing, Inc. Dist. by United Feature Syndicate Inc.