Category Archives: book promotion

Ptolemy—why not take Ptolemy?

Ptolemy showing his geocentric model of the universe. That’s Earth in the middle.

We’re coming up on the Middle Ages, everybody! The Roman Empire has become the Holy Roman Empire—we’re still working on creating individual countries out of the territories of various tribes. The Christian Church has become a stabilizing institution. With Charlemagne’s help, religious centers—like monasteries—are also places of learning. Alcuin of York (Charlemagne’s right-hand man) designed an easier-to-read way of writing using capital letters and small letters instead of ALL CAPS!

Life isn’t easy for regular peasants, which is most people. It’s hard to make a living on a farm. Some people head to the towns to learn a trade. Sanitation isn’t so great and the bubonic plague is always just around the corner. It will be centuries before anyone figures out that plague is carried by fleas.

It usually takes a long time for civilizations to accept new ideas. Even after Eratosthanes showed the Earth to be round, many people thought she was flat. Both educated and uneducated people believed that the Earth was the center of the universe and the Sun, planets and stars revolved around her. They thought of the universe as a giant sphere—a ball—with planets and stars stuck onto it. This sphere would be like clear glass. The word for this idea is geocentricgeo is a Greek word for Earth, centric means smack dab in the middle.

We get this idea from an astronomer named Ptolemy (TOE-leh-mee), who lived in Alexandria, Egypt (100-170 ad, we think). He improved on the basic geocentric idea. Ptolemy used math to place the stars in fixed positions on this big sphere. He observed that the planets didn’t stay fixed on the sphere, though, so they were called wandering stars and got their own smaller spheres that fit inside the big one. The Sun made its own orbit, a circle, called an ecliptic.

Here’s Billie Holiday singing “All of Me.”

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https://www.britannica.com/biography/Ptolemy
https://www.teachastronomy.com/textbook/The-Copernican-Revolution/Ptolemy-and-the-Geocentric-Model/

It’s better than bad, it’s good

There is a mention of an hourglass in a ship’s inventory in the 1300s.

When you need to know where you are at sea, this is what you have to go on.

At sea, it’s difficult to know exactly where you are. No landmarks. No way to tell how far you are from land. Sailors had to be creative. To figure out distance, they used time.

Sailors liked the hourglass because it isn’t as affected by a ship’s bouncing around on the waves as a water-clock would be—it still marks an hour accurately. Smaller sandglasses with less sand mark shorter periods of time. Sailors could judge how fast their ship were traveling by ‘casting the log.’ They had a length of line—heavy cord—with a piece of wood (the log) tied to its end, and knots tied in it at regular intervals. They’d throw the log into the sea and turn the glass at the same time. The log dragged behind and pulled the line with it. When the sand ran out, they’d nip the line and count how many knots had run out. Number of knots = distance traveled in a set space of time.

If you know how fast you’re traveling, you can make a guess how far you traveled in an hour or a day or a week. This is how the sailors used to calculate where they were on the ocean.

Casting the log is said to have been invented in the 1500s. The first evidence of a ship’s log-book is from the 1600s. This is a guess, but it seems to me that the log-book would have been originally a record of the ship’s speeds—that eventually became a record of any important events that happened aboard the ship. With time, ‘log-book’ got shortened to ‘log.’

Today, people who post regularly on the worldwide web refer to their sad ramblings as a ‘web-log’ or ‘blog’ for short. Spare a thought for us poor, attention-starved souls.

Here’s an excellent video about casting the log.

https://www.britannica.com/technology/log-nautical-instrument
https://en.wikipedia.org/wiki/Chip_log
https://www.archives.gov/research/military/logbooks/naval-deck-logs.html

The secret origin of “log in”

More about time and distance.

Read this now! Time is running out!

Hourglasses are good timers that are easy to use, so they’ve been part of people’s lives for centuries. My mom used to have a little one that measured 3 minutes—just right for boiling an egg.

The hourglass became a symbol for time itself, and just how quickly it seems to pass. Go into an old cemetery and you might see one carved into a tombstone—eeek!

On some computers a little icon of an hourglass shows up to tell you that your program is still loading.

By golly, I would have committed murder to own that Wizard of Oz hourglass when I was an art student, How about the lucky prop artist who got to design it!

If you ever saw the old Wizard of Oz movie with Judy Garland, you’ll remember that terrifying big hourglass that belonged to the Wicked Witch of the West. Here’s a website that tells how hourglasses are made. This one’s good, too.

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Hourglasses

An hourglass is a device that measures time. It’s two glass bulbs joined together by a skinny neck. There’s sand inside, so when you set the hourglass with the sand-filled bulb on top, the sand trickles through the neck into the empty bulb below. The hourglass maker put in exactly an hour’s worth of sand, so when the top bulb is empty, one hour has passed. The whole contraption is contained in a frame so it can be stood on either end.

Hourglassses are sometimes called ‘sand clocks,’ but they’re timers. Remember the early Egyptian water clocks? They were timers, too, until Ctesibius figured how to make clocks out of them.

Legend says that a French monk called Liutprand (Lee-UT-prond) invented the hourglass in the 8th century ad. There doesn’t seem to be solid evidence to support or deny that. Charlemagne is supposed to have owned a 12-hour hourglass—Liutprand was French, Charlemagne was French, so maybe there’s a connection? And I guess I’d have to admit that at 12 hours, that hourglass was a clock.

https://www.guinnessworldrecords.com/world-records/first-hourglass

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Julius Caesar painting exercise

I just got a clamp-on holder for my phone and wanted to try this—

Update: Sorry for any confusion if you visited here in the last hour. I couldn’t get the video to show up. I’ve since added a link to Instagram. I hope that works! Thanks for your patience.

 

May we be Frank?

Throughout this history I’ve been trying to keep it zippy. Not too many words. No excess verbiage. Avoid the chit-chat. Anyway…to do that I’ve had to shrink down some larger-than-life personalities into one or two paragraphs. Charlemagne—also known as Carolus Magnus, Karl der Grosse, Charles the Great—is one guy who can hardly be covered in a book, let alone a blog post. But I’ll give it a whack.

After the western half of the Roman Empire fell to barbarian invasion in ad 476, civilization and culture had a tough time of it. From the north and west, people who would later become the French, the Germans, the Spanish and the Italians all fought within the empire. People from the MidEast also wanted to take over the empire. This state of constant warfare lasted more than a couple of centuries. Forget about culture—nobody could relax long enough to create art or music. Then in the 600s one tribe, the Franks, started fighting better than everybody else and a dynasty was begun—a ruling family who set up some stability and order using military power. The Carolingian Dynasty started with Charles Martel, then his son Pepin, then Charlemagne. Charlemagne was a ruler who rode at the head of his army and whupped the other armies. He brought more than peace to what had been the Roman Empire—he encouraged the arts, education and literature.

Remember that Christianity was the empire’s official religion since Theodosius. Pope Leo III was Charlemagne’s biggest fan and had Charlemagne crowned the Holy Roman Emperor in ad 800. After that, Charlemagne began a program of standardizing many parts of the Holy Roman Empire’s way of doing things. He relied on his right-hand man Alcuin of York to make much of this happen. Alcuin was a gifted innovator—he came up with cultural inventions that are part of our culture today.

F’rinstance, Charlemagne noticed that churches throughout the empire would sing a particular hymn, but each church used a different tune. He decided they should all sing a hymn using the same tune for that hymn, so Alcuin invented musical notation. With a songbook you can read how a tune should be sung. Charlemagne thought that the Roman way of writing (ALL CAPS) used up too much space and was difficult to read, so Alcuin invented upper-case and lower-case letters, like what you’re reading here.

Here’s why I’m telling you about Charlemagne. He liked Little Dennis’ Anno Domini system, so Charlemagne made AD and BC the Holy Roman Empire’s official way of numbering the years.

Just as it still is today.

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Everything AD does but backwards, in high heels

Long ago, in the dim misty recesses of history, there was a famous dance couple: Fred Astaire and Ginger Rogers. Their dance routines were stylish and glamorous—and captured in movie musicals so you can still watch them. Fred and Ginger made dancing look easy by putting in a lot of rehearsal time.

Ginger once joked that not only did she do everything Fred did, but she did it backwards, in high heels.

If you thought it was hard to figure out how the centuries are referred to in Anno Domini, how do we ever count back the centuries Before Christ? We live in the 2000s and call it the 21st Century. The 21st Century ad starts with 2001 and ends with 2100. How does that work in bc, where you count backwards?

Let’s pick a century. How about the 4th century? The 4th century Anno Domini started the first day of ad 301 and ended the last day of ad 400. It’s just the opposite in bc. The 4th century Before Christ started the first day of 400 bc and ended the last day of 301 bc.

Are you getting a headache yet?

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What century is this anyway?

All the years in this century start with 20… So how come it’s called the 21st Century?

Well, first of all, not all the years start with 20… The very last year of this century, its 100th year, will be 2100.

It works just like your age. Are you 12 years old? That means you’re in your 13th year. When you’re in your 21st year, you’ll be 20 years old until the very last day—the day before your birthday. Then on that birthday you’ll be 21 years old and in your 22nd year.

Anno Domini is in its 21st century, and is 2019 years old. December 31, 2100 will be the last day of the 21st Century. On January 1, 2101, AD will be in its 22nd century.

The Venerable Bede

What about all those years before Jesus was born? Don’t they get numbered, too?

I thought that a derby and a brolly would make him look more English.

In ad 731, an English monk, the Venerable Bede, wrote the Ecclesiastical History of the English People. He used the Anno Domini numbering system to date the years when events happened. Bede is considered to be the father of English history. Ecclesiastical means having to do with the Christian Church.

Bede’s History (5 volumes!) included events that happened before Christ was born. He numbered those years going backwards, starting with the year 1 Before Christ (bc for short). We still use bc and ad to number years. Lately it’s become fashionable among fancy-pants academic types to call Before Christ ‘Before Common Era’ and Anno Domini ‘Common Era.’ We use bc and ad in this history to honor the achievements of Bede and Dionysius.

‘Venerable’ means ‘honored’ or ‘revered.’

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Little Dennis

dennis570

At the Council of Nicaea a lot of things were agreed upon. One thing the western and eastern halves of the Roman Empire could not agree on was when Easter should be celebrated. Each half—western and eastern—celebrated on a different date. This went on for a long time until finally in ad 525 an expert was called in. Dionysius Exiguus (his name means ‘Little Dennis’) was a scholarly monk who got the job of figuring out exactly when the Christian holy day of Easter should occur every year.

Dionysius decided to go back and find when the first Easter occurred. Jesus’ resurrection happened during the Jewish Passover—Pesach. The Jewish calendar relies on the motions of the Moon and Earth’s orbit around the Sun. Using some incredibly complicated astronomical calculations, he was able to arrive at the original date.

Dionysius realized once he’d found the date of Jesus’ resurrection, he could then figure out when Jesus was born. Jesus was 33 years old when He was crucified, so Dionysius counted back 33 years from the first Easter to get the year of Jesus’ birth.

In the past, years had been named after whoever was the imperial consul at the time. Dionysius decided it was time to change that. He named the years after Jesus, the Christian Savior. So the years beginning with Jesus’ birth are numbered and called Anno Domini (ad for short)—Latin for ‘the year of our Lord.’

By the way, Dionysius reckoned that Easter should occur on the first Sunday following the 14th day of the lunar cycle—the full moon—that falls on or after the spring equinox.

Back to the beginning of The Western Civ User’s Guide to Time & Space.

https://www.encyclopedia.com/people/history/historians-european-biographies/dionysius-exiguus
https://www.britannica.com/biography/Constantine-I-Roman-emperor