Sunday, September 28, 2014
Sundials were invented to solve this problem. Because they measure small intervals of time using cosmic activity, sundials were considered to be one of the earliest scientific instruments. The Egyptians were the first people recorded in the West to use the sundial. Their sundial consisted of the gnomon (a crossbar) and a flat base divided into six “hours.” In the morning, the gnomon faced east, and the afternoon west. The shadow cast by the gnomon on the base determined the hour.
Using their knowledge of geometry, the Greeks refined the sun dial of the Egyptians. They invented the hemicyclium (hemispherium), which is a block of stone with a hemisphere cut into it. The gnomon was placed on top. The half-sphere created a circular arc that determined time more accurately. The hemicyclium resembled a hollowed out bowl with a stick on top.
Sundials used in Europe were adapted from the Greeks and the Egyptians. These instruments featured twelve “hour” days and nights. However, the Norse and Saxons based theirs on the ebb and flow of tides. They marked two high and two low tides, which were further divided into halves and quarters for a total of sixteen “hours.”
One major problem with ancient sundials is that they measured “unequal” (“temporary”) “hours.” Summer, which has longer days, produces longer “hours,” than winter. Moreover, the further north (or south) from the Equator, the location of the sundial is, the more pronounced the difference between summer and winter “hours” are.
In the 1300s, Abu’l-Hasan (Ibn al-Shatir), an Arab Muslim astronomer and religious timekeeper, invented “equal” (“equinoctial”) “hours” based on trigonometry. He reasoned that a gnomon parallel to the Earth’s axis (i.e. polar axis) would produce “equal hours.” “Equal hours” are measured from the passing of the low meridian (12 Midnight) until the next low meridian, and then divided into twenty-four hours. Once sundials were adjusted to the latitude of where they were, they kept accurate time. People, then, used sundials to set mechanical clocks.
Sundials are divided into two groups – Altitude and Azimuth. The Altitude sundials determine time by the sun’s altitude. These Altitude sundials were either aligned with either the sun or the cardinal directions. Azimuth sundials determine the time from the “hour angle of the sun.” (Azimuth refers to direction of the sun’s angle.) These sundials are oriented by a compass.
Example of an Altitude sundial is the pole (pillar) dial, which is a pole with a gnomon at the top. Meanwhile Azimuth sundials are often found in gardens. These are the tilted horizontal ones with the gnomon inclined at the latitude of the garden.
As society became more complex, instruments to tract time in finer increments were invented. Though seemingly simple, sundials are actually intricate devices for keeping time. Because of their importance, people, over the centuries, worked to improve sundials. In fact, sundials were still being used in the 19th Century to set mechanical clocks.
Ling Liew Huay and Yee, Lim Siew, “The Mathematics of Sundials,” National University of Singapore, 2001, http://www.math.nus.edu.sg/aslaksen/projects/sundials/
Marie, Niclas, “When Time Began: The History and Science of Sundials,” TimeCenter, 2014, https://www.timecenter.com/articles/when-time-began-the-history-and-science-of-sundials/ .
Nordoff, Helena, “Fun in the Sun: A Sundial Tutorial,” 21 August, 2003, http://www.qwerty.co.za/sundials/index.html.
“Unit 6: Sundials,” Polaris Project, Iowa State University, 2001, http://www.polaris.iastate.edu/NorthStar/Unit6/unit6_intro.htm.
Ward, John and Margaret Folkard, “Sundials Part 2: Definitions and Basic Types,” Royal New Zealand Institute of Horticulture, 1997, http://www.rnzih.org.nz/pages/sundial2.htm.
Monday, September 22, 2014
Between places of
Not coming or going.
Crossing Thresholds is
Not all at Thresholds
But Heroes must
But Guardians must
To keep in and to keep out.
Before from after
In between secure
Doors have Gods
Janus of Two Heads guards the Out and the In
Cardea of the Door stands firm
Limentius of the Threshold stands firm
Portunus of the Portal holds the key
A reason for opening
A reason for closing
Forculus of the Passage
Only One Transforms.
Goodin, Melinda, “Archetypes in the Hero’s Journey,” Crossing the Threshold, March 2004, web, http://members.optusnet.com.au/~mgoodin68/archtype.htm
Peterson, Deb, “The Archetypes of the Hero’s Journey,” About Education, 2014, web, http://adulted.about.com/od/howtos/a/archetypes.htm
---, “Threshold Guardians,” Television Tropes and Idioms, web, http://tvtropes.org/pmwiki/pmwiki.php/Main/ThresholdGuardians
Vega, Debra, "Writers, Know Your Archetypes: The Threshold Guardian,” Moon in Gemini, web blog, 5 January 2014, http://debravega.wordpress.com/2014/01/05/writers-know-your-archetypes-the-threshold-guardian/
Wednesday, September 17, 2014
Noted for her well-developed limbs and deeply forked tongue that flicker in and out like a Snake's, Goanna is a distinctive looking Lizard. Long and stout, She has a tail that strikes out at her enemies. An active forager, Goanna digs out other Lizards, Insects, and small Mammals to eat.
This fierce looking Lizard is shy and timid but can be quite territorial and agressive when confronted. An excellent tree climber, Goanna will scoot up a tree trunk when danger threatens. Her reckless speed in escaping is legendary among Australians. They joke about scared Goannas racing up people’s legs thinking that they are trees. Australians advise to lie down when Goanna runs at you, and remember get treated for her bite. (It is not poisonous but can cause sickness.)
Among native Australians, Goanna is considered to be lazy. They tell stories of how ingenious Goanna was in climbing trees to get bark to make a canoe for sailing to Australia. However, when industrious Goanna arrived, She became lazy. She stopped farming and started stealing food from Echidna instead.
However, when She is confronted, Goanna races out of danger. Her most noteworthy characteristic is her speed, which serves Goanna well. Like Goanna, we can explore but be prepared to race away when danger threatens.
"Curiosity killed the cat but information brought the Goanna back." Goanna is forever looking into what is going on around it. Using its powerful body and legs, it climbs trees and rocks to find out what’s going on over there! Goanna’s tongue flashes back and forth from his mouth, as he tastes the air to find out who’s about. He calmly saunters along poking his nose into all manner of mischief but, forget not, that should Goanna feel the need for speed, there is nothing to see after the dust has cleared. Copyright: “Wisdom of Australian Animals,” Ann Williams-Fitzgerald.
Saturday, September 06, 2014
Ranging from shy reclusive Goannas to nasty and aggressive Komodo Dragons, Monitor Lizards often fill the niche of predatory and scavenging Mammals. Active foragers, Monitor Lizards will swallow their prey whole. What distinguish this Family of Lizards are their well-developed limbs and forked tongues.
Extremely hardy, Monitor Lizards have aggressive temperaments, a powerful bite, and a lashing tail. At the slightest provocation, They lash out with their tails. Although their tails produce a stinging lash, Monitor Lizards do not lose their tails like other Lizards.
Crocodile Monitor (WhoZoo)Monitor Lizards have inspired much of people’s mythology such as dragons, which often resemble these Lizards. Because of Monitor Lizards’ aggressive natures, peoples of Borneo put images of Them on their shields to strike dread in the hearts of their opponents. In Thailand during the full moon, some unfortunate people became “were-monitors” prowling about for victims. Ancient Egyptians excluded Monitor Lizards from their after life since They preyed on young Crocodiles, who represented the Egyptians’s beloved god, Sobek. Meanwhile in Australia, stories abound of industrious Goannas inventing bark canoes for traveling.
Monitor Lizards fire people’s imagination. Dragons are their big brothers. Believing Them to be poisonous, People have thought of Monitor Lizards as “were-lizards”. Australians tell stories of how Goannas learned to climb trees to make boats. Let Monitor Lizards feed your imagination. Just remember not to be anti-social and lash out.
Note: Alligator Lizards (Anguids) are close relatives of Monitor Lizards. Scientists think that Snakes are related to Monitor Lizards as well.
Conservation Note: Monitor Lizards are threatened and endangered in part of their range from the pet trade and leather trade. Komodo Dragons are protected in Indonesia.