Midwinter calling, day 42

Tick-Tock

The pendulum clock mechanism seems to work fine. It's a bare clock mechanism with no case and the clock face is a sheet of paper with a drawing. For now we just hang it on the wall in the great hall. It's to check that it works well, and we will finish fine-tuning it with the help of my wristwatches and mobile phones, and see how often the weight needs to be wound up to improve and adapt future models.

The pendulum is one meter long and is an aerodynamic pendulum arm and brass weight whose position/length can be adjusted with a spring locked screw at the bottom, and the pendulum moves about 5 degrees between outer positions. A pendulum cycle takes two seconds, and its spiked wheel has 30 tooth's per revolution so the gearing is really simple to get a minute, and similarly simple for the hour hand. It is a 24 hour model and to add a minute hand through the hour hand shaft was just an unnecessary complication, so the prototypes minute hand is to the side on its own small face, and so is the seconds hand below. The second or minute hand is really practical for quickly making the adjustment by comparing time with the wristwatch or mobile phone. Has the pendulum clock gone 60s but the mobile phone and the wristwatch show 56.5s? Adjust the pendulum slightly longer. Has the pendulum clock passed 10 minutes when the other shows 10m7s? Adjust a tiny bit shorter. Each pendulum clock will need to be adjusted individually, but this gives experience. As long as there is just one clock it doesn't really need to be that exact and for most people it won't really matter. We will have many clocks in just this building, and the same applies for the Academy, and to avoid adjusting many pendulum clocks and having clocks that strike differently, I'm quite keen to make a pendulum clock that creates an electrical pulse every fifteen seconds or so, and simply build 'clocks' without a timekeeping part where an electromagnet advances a wheel like in the servant system, with just gearing for the minute and hour hands. Far less work than building real pendulum clocks, and they will all run in sync and be cheaper and smaller, and I can even make that electromagnetic mechanism so silent that it basically doesn't tick, which would be nice. Ticking is annoying.

Still, pendulum clocks will be the primary clock for everyone else probably for a century or more, so I will try to make a temperature compensated pendulum in metal rods that have different lengths of expansion. Maybe it will be iron and zinc, tin or brass, but I just haven't bothered to figure out what is most suitable to do and make the metal bars for it, and I just made the prototype pendulum clock. The principle is quite simple; one metal that will be iron that expands less builds downwards, and others that expand more lift upwards. If you balance with the right lengths in relation to the expansion coefficient, the changes in length cancel each other out when the temperature changes, and the watch keeps more accurate time. Another trick is to put the pendulum in a sealed vacuum and keep it at the same temperature.

Jane facepalm when I tell her that way back historically with the first mechanical clocks in monasteries etc, the day was divided into 12 hour periods and the night also had 12 hours. Regardless of the time of year or location on the Earth. They adjusted the ticking of the clock to match the day, and instead of a pendulum, they had a rotating solution with weights they could move in or out to adjust how long the hours of the clock were depending on the time of year. And that also had to change at sunrise and sunset since a long day required a short night. Neither Jane nor I can understand why they didn't use an adjustment table for day of the year when they usually had a person ringing the church bells anyway, but they did it the way they did. I suspect that there will be quite a few versions of bells and complications in the future as I am kind of keen to make a clock that shows the day of the week, month, moon phase, date, etc. It might even be a cuckoo clock although I would have liked to have some kind of Aesir religion variant instead, like a raven if I can build some kind of mechanism that sounds vaguely raven like, which wood against wood might do, much like adding a playing cards in the spokes of a bicycle wheel. I personally don't want clocks making noises, but others might like it.

The elves have to learn to read the clock, which only Jane takes for granted everyone should just know how to do, apparently not remembering that that is taught in school. But that is not what's on the top of her mind right now.

"Why the bloody hell did you do a 24 hour clock?! You could at least have put 12 at the top instead of the bottom. This is just idiotic!"

"Jane, why is 12 hour clock face better?"

"What?"

"Justify why a 12 hour clock face is better than a 24 hour."

She wasn't expecting that and Jane starts to reply but holds her tongue as she actually think about it. I can see her getting more frustrated and annoyed as she obviously can't think of anything good, while she knows that I will have good reasons since I made it 24 hours. Eventually she just closes her eyes and resignedly say: "It just is."

"Well, with a 24 hour face and time, you don't have to mention AM or PM, and 24 hour time and faces is used in scientific contexts, in military time, polar time and when dealing with time zones. Just a quick look and you will know. 24 hour clocks was also used really far back until it became fashionable with 1-12 watch faces in Europe which we had to live with since. It is better that the elves learn to read a 24 hour clock which also match with solar time, and I already marked all the sundials with a 24 hour scale, but that was admittedly out of sheer habit. Any division including Decimal time would have worked, but more annoying for us to learn, and it's so much easier for the future to have 24 hours, 60 minutes and 60 seconds, just for all the scientific measurements and stuff I introduce, and if they ever make proper contact and exchange people and goods with Midgård. Anyone claiming that 12 should be at the top because that is when the sun is at the top, and that summer-wintertime is stupid, should also want a 24 hour clock since then the hour hand will actually match the movement of the sun. If you're in the northern hemisphere and the clock is set up due south being read from the north. But a sundial use the shadow, and the closer to the Equator you are the more vertical the scale becomes, and 12 will be..."

"... at the bottom." Jane answer my prompting in a low voice, but she is not happy.

"Anyway, that small round thing with the spikes on the back end of the hour hand is a small sun symbol, and it goes up and down quite logically."

"Oh, that is suppose to be the sun. Okay, that is kind of nice, and I admit it is a good design from a functional, scientific and logical point of view." I can't help but feel quite smug, and Jane's eyes narrow as she gets a menacing look. "But 12 hour is better." Jane dares me to say anything, before she turn around and leave.

Maybe I should give Jane her own pendulum clock with a 1-12 face. That goes backwards. I just have to reverse the direction with gearing or reverse the first spiked wheel and the anchor. If I make a pretty clock face with just markings or decorations for all the hour positions except 12 and 6, Jane won't realise it until the hour hand start moving. Oooh! I can make the minute hand move in the right direction and reverse the hour hand! That will annoy the heck out of her! I can add a lever or push button mechanism with extra gears, or just prepare it so that the gearing is via a small gear that can be replaced with two and thus change direction. I could then also make it change to 24h time so she has to choose between counter-clockwise 12h or clockwise 24h.

A Vetinari watch would be even more fun, but more difficult. I could make the second hand completely disconnected from the minute and hour function, and put the second hand on a slightly misshapen gear to somehow change the angular speed of the rotation, so that a revolution or two is still correct but the tempo between steps differs. The problem is that the tick-tock from the pendulum will not be unsynced and the sound would absolutely be the most effective if it is a little off. I might try making an asymmetrical pendulum wheel and see if I can still get a clock to go right, although it will be very inefficient and probably need to be wound up more often. Or a small silent higher speed pendulum hidden internally drives the clock while the large visible pendulum that makes more sound is to annoy? Pendulums on the same platform tend to synchronize and transfer energy between each other, so that might be an issue even with different lengths. Can I exploit that phenomenon? If it is an electrically controlled 'clock' where the hands are actually controlled by a time signal, then the pendulum doesn't matter, and a pendulum that slows down and stops, and then increases to full swing again and goes back and forth would be annoying and confusing. A pendulum that behaves weirdly, that makes noise even though it is standing still, connected to an asymmetric second hand where the minute hand is right over a five-minute intervals would be fun to have in a waiting room or similar. The problem is that people won't be used to pendulum clocks and instinctively know how they should run and sound.

Damn. Jane is pretty much the only one I can annoy, maybe for a decade.