Sunday, August 5, 2012
Clockwise Shadows (Smithsonian Castle)
Sundial, Smithsonian Castle Garden, August 5, 2012. 1:15 pm. Latin inscription (left on this photo): Aspice, Respice, Prospice = "Look Around, Look Back, and Look Forward" (or, more loosely translated, "Observe, Reflect, and Think Ahead").
Some observations: You'll see that "north" (and 12 o'clock) on the middle right in this photo; I oriented the image to better reveal the shadow of the gnomon (rod) that's indicating the time. Over the course of a day, the Sun causes the shadow to around the sundial in a "clockwise" direction. The only reason mechanical clocks go "clockwise" is that they follow the motion established by earlier sundials - if sundials (and clocks) had been invented in the Southern Hemisphere, they'd now be going in the "other" direction.
Numbers on the clock are indicated in Roman numerals. The number "four" is indicated as IIII, after the Roman fashion; the form "IV" was actually a later (medieval) development.