63. Pendulums
Thuorfosi, at the Building Shrine of Giltak in Omexkel
Dinner tired Emily out. I haven't decided if this was a good thing or a bad thing. The only modification to the chair for Emily was a pile of cushions. Though she could reach, it was at the expense of her lower back muscles. The seating arrangements put Emily between me and Raoleer. This means they talked furnaces and metal all dinner. Emily ended up kneeling on the chair so she could write and diagram things for Raoleer.
Emily was tired enough after dinner that she fell asleep with her head on my shoulder while walking back to the guest house. She did not wake up when we got back. I put the sleeping lump of Emily to bed. At least the guest house had rooms sized for Coyn. It didn't make my life easier, but it was more comfortable for her.
Raoleer wanted to show Emily the different furnaces already built for tin and copper and something called zinc. In the morning, High Priestess Lisaykos and I both agreed that Emily needed a rest day. Emily didn't agree, but since she was too sore to sit up in bed without help, her disagreement was moot. She dozed all morning. When the midday bell rang, High Priestess Raoleer and my mistress both appeared at our quarters. We woke up Emily and headed to the mid repast in Raoleer's private dining room.
Lisaykos had counseled Raoleer not to bring up metals or furnaces today because Emily gets too excited talking about them. Instead, Raoleer broached the subject of time measurement. This was a mistake because we discovered that Emily was also passionate about measuring time. At least her back was sore enough that she didn’t make it worse by writing at the table during the meal.
I may have witnessed the world change at mid repast. Raoleer and her artificers had a problem trying to measure time. Emily solved it at the table as we ate. In yet another "Emily moment," as the Blessed Lisaykos liked to call them, Emily listened to the Holy Raoleer describe the shrine's pendulum problem and then popped out an answer. I didn't understand most of what she and Raoleer were talking about so don't blame me if this isn't accurate. I'm just a priestess healer, not a priestess artificer.
The High Priestess Raoleer told the Blessed Emily about a strange behavior of the big pendulums: they didn't travel back and forth in a straight line like everyone expected. Emily nodded her head as if she expected Raoleer's description of the strange pendulum movements. Her explanation showed that she even knew Sekoy's Law, which should have been impossible. The things she said about pendulums were incredible.
It is such a mystery to me how Emily knows so much. Where does all this knowledge come from? I sometimes think she might be the prophet in the Prophesy of the Great Breaking. She shows the signs of high favor from the gods: she's the first Coyn to be a revelator, the first person to receive revelations from more than one god, and the recipient of multiple dream commands. She is just too strange at times. If Artificer Sekoy's pendulum mechanics were just published two years ago, then how did Emily know so much about the subject?
Pendulums are important right now at the Shrine of Giltak because their use might solve the problem of measuring shorter periods of time. Longer periods are measured using the ten bell system calibrated off sundials and the motion of the stars. Daylight is divided into six equal parts using seven bells. The first bell is at dawn, the fourth at midday, and the seventh at dusk. The night is divided into quarters, with three bells.
This system is easy for those who have sundials, star maps, and correction tables provided by the Shrine of Tiki; however, bells and sundials are not useful for anyone who needs to measure a smaller division of time. The bells have the additional problem that the time between bells changes every day because days are longest during the growing season and shortest during the cold season.
There is no uniform way to measure short periods of time. At the Shrine of Mugash, we have our own measure not shared by anyone else. We use the finest white beeswax candles cast in uniform molds with marks for one-eighth of a bell on them as measured on the day of the equinox.
Priestess Artificer Sekoy discovered that the time it took for a pendulum to travel back and forth depended on the square root of the length of the pendulum. This is now known as Sekoy’s law. Sekoy then realized that large pendulums could help solve the time measurement problem for both long and short periods.
The shrine made several large pendulums and hung them in the third chamber in the Shrine of Giltac to find the conversion that turned pendulum length into time. If the unknown number was the same for every pendulum length, then large pendulums could provide better and more uniform timekeeping everywhere. It sounded clever to me. Priestess Sekoy must be a very smart lady.
The High Priestess Raoleer told the Blessed Emily that the pendulum ball on each pendulum was displaced to the left every time it swung, and it happened for every pendulum regardless of its length or the size of the weight.
Emily nodded, not at all surprised or perplexed. "Holy One, that happened because the planet moved to the right underneath each pendulum,” Emily remarked as if this was obvious. “By hanging each pendulum from the ceiling, y...you essentially put each inside its own inertial reference frame." Emily looked at Raoleer’s confounded face as she digested Emily's statement.
"Before y...you protest, Holy One, that if this were true, then w...why did the pendulum take a day and a half, give or take a bell, instead of just one day, to complete its circuit of the circle and return to the position where it started?
"The answer is that the inertial reference frame of the pendulum is also rotating about the rotational axis of the planet but at a speed w...which is determined by the inverse of the latitude of the pendulum, w...with the latitude at the equator being defined as zero. So the time that the pendulum takes to make the complete circuit of the circle is one day divided by the sine of its latitude. If y...you draw it out with all the angles identified, you w...will find that this is indeed correct. The closer you get to the equator, the longer it w...will take the pendulum to make a full rotation w...within the circle of its reference frame.
"W...when the pendulum is at the equator, the plane of its travel is now fixed relative to the planet, and the time it takes to travel the circle is now infinite. In other words, the inertial reference frame of the pendulum is rotating around the planet's axis at the same speed the planet is rotating, and it w...will never trace out a full circle. It w...will only trace out a line.
"At the poles of the planet, the pendulum w...will trace out its circular path in exactly one day as its inertial reference frame is stationary and the planet revolves underneath it. If you give it a little thought, Holy One, you'll realize that you could use your massive pendulums as a w...way to accurately establish latitude and calculate the curvature of the planet to a high degree of accuracy, simply by measuring the time taken to make a complete circuit of a circle by the pendulum at different locations."
Emily looked at Raoleer, who looked beyond gobsmacked. "Did I lose y...you somewhere, Holy One? I'm interested in this because I've been w...w...worrying about trying to standardize units of time, distance, mass, and temperature. I planned to ask you about this very subject w...while I was here."
Raoleer closed her eyes and shook her head. "How can you know all this?"
"It's simple," Emily said a bit defensively. "Just start from first principles. The planet is round. The planet orbits the sun. The planet rotates about its axis, one planetary rotation per day. Because we have seasons, we know the axis of the planet has to be tilted; otherwise temperature w...would vary only by latitude and not by the time of the year.
"You've got the hard part down, Holy One, w...which is the experiment to find the missing constant that relates pendulum travel time to the square root of the pendulum length. Throw in the equation for simple harmonic motion, and you can calculate everything else with knowledge of how geometry works. Right?" Emily's face was cheerful and optimistic as if this was the easiest thing in the world.
Raoleer's expression just got more incredulous. "How old are you, Great One?" Raoleer gave Emily a penetrating look.
She answered honestly, "I don't know. I never knew my parents and I never had a family."
"You've never been to any kind of school?"
"That is correct."
"Who taught you to read and write?"
"Lisaykos taught me to read and write in Fosk."
Raoleer looked at the Blessed Lisaykos, frowning.
"That's the truth, sister," my mistress said without even blinking.
"Where did you learn your mathematics skills?" Raoleer turned back to Emily.
"W...when I was younger, I w...was captured by some Cosm. The first time they whipped me, I woke up the next morning in a fever, and most of what I know w...was stuffed in my head."
"Most?"
"Now and then, the gods decide t...to mess with my head and put more things in it," Emily said with bitterness and just a touch of anger. I had never heard her talk like this before. The bitterness surprised me. Why did she not feel grateful for such a wonderful gift from the gods?
"Unbelievable." Raoleer studied Emily for several breaths. “What is the equation of simple harmonic motion and what is an inertial reference frame?”
Emily’s fish face was impressive, “y...you don’t know?”
“Maybe I should get Sekoy and you can explain this to us?”
“Not this afternoon, sister,” Lisaykos smiled at Raoleer, “not if you want her to make sky metal tomorrow. She won’t rest if she spends the afternoon talking with you. You bring out the worst in each other.”
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Jane, who can not remember her Foskan name, in the Fenlands.
* Jane dear, what you need to do is to use the charm of undoing, the spell of creation, and the spell of repair, in that order, and the tightness in your clothes will go away. I had to do it to myself several times over the last few millennia or so, but then again, my exoskeleton is my clothing. *
"This is quite upsetting," Jane said, "I was too big to begin with, and now I'm getting bigger? People are too scared of me as it is." She closed her eyes and shook her head. A lonely tear escaped down her cheek.
* Oh! Jane! You remember that people were scared? Follow that thought if you can. Who was scared? When did this happen? *
"I...I...," she frowned in frustration. "I just know people were scared of me...and...and I was lonely all the time. I don't remember anything else."
* Ah, but Jane dear, you just remembered another thing you didn't remember before. You see, it is getting better. You already remember your old name and some of your previous life. You need to be patient, dear, and give it time. Some of your memory is already returning. *
"What good is memory, Ud, if everyone runs away from me?" she remarked with bitterness.
* You don't know that everyone ran from you. Some probably did not. They were your friends, and you will want to see them again. I am certain that they are missing you and looking for you. Seriously, look at the monstrous me. Even you screamed when you first saw what I looked like, and yet, here we are, having a cup of tea and a nice chat on the beach. Shallow people will only see the outside of you, but your friends will see the beauty of you on the inside, which is what matters. *
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