He thanked her and went back to his house. There, he picked up the two stones that were inside the wardrobe. I'm so dumb, he thought, shaking his head at his oversight.
He tore a small piece of rag and placed it near the wood inside the fireplace. Striking the stones together, he managed to produce some sparks and ignite the rag.
I need to find more wood tomorrow, he reminded himself as the fire began to cast light across the room. Placing a chair in front of the fireplace, he sat down and began eating his soup. Okay. Now that paper is set, what will be next?
After finishing his meal, he grabbed the book and decided to finish Chapter 3. The last indispensable technology, let's see what it is, he thought as he searched for the right page.
[3.5. Calorie Surplus: The End of Hunting and Gathering, and The Beginning of Civilization
Hunting and gathering better ways to live your life.]
The chapter began by explaining how, in the early days, our ancestors relied solely on hunting and gathering, never staying in one place for prolonged periods: It costs calories to search for food. As he read, Rafael reached a conclusion: Hunting and gathering suck.
The next paragraph discussed the invention of farming and its advantages: (...) you have entered a new phase of humanity, one in which a single human can reliably produce much more food than they need to survive. This abundance allowed civilization to flourish, enabling more people to focus on intellectual pursuits rather than merely surviving day to day.
That's what I need. I need intelligent people to help me build this civilization, Rafael thought, realizing the importance of collaboration.
The book also pointed out the downsides of farming:
[*When wild food is abundant, farming is way more work than hunting and gathering. (...)
*Farming also requires technologies for food storage but you can see Section 10.2.4: Preserved Foods for that. (...)
*Farming creates the first income inequality. (...)
*Farming requires infrastructure (fences, etc.). (...)
*Animals carry diseases and can transmit them to humans. (...)]
"It's good that the book informed me about these cons, but the pros are vastly superior," Rafael mused aloud. "I think most of these technologies—no, not all of them—have been invented yet. Spoken and written language already exist, and so does the concept of calorie surplus. I just have to see what number system they use."
The sun had set not long ago, so Rafael decided to continue reading the next chapter.
[4. Units of Measurement Are Arbitrary, But Here's How You Can Reinvent the Standard Ones Used In This Book From Scratch
Can you really reinvent measurement while trapped in the past? We wouldn't . . . rule it out.]
The first part explained how temperature systems work with Celsius, Fahrenheit, and Kelvin.
"To make a thermometer, I'm going to need glass, and that doesn't seem so easy to make, even with this book's instructions. But it's good to have this knowledge at least," Rafael said, considering the challenges ahead.
The book then discussed the kilogram, explaining that until 2019 CE, it was based entirely on a physical cylinder of platinum, with copies stored around the world. A kilogram is however much that hunk of platinum weighs. But what caught Rafael's attention was why this method of measurement was eventually abandoned.
When scientists verified the weight of these copies, they discovered variations among them, and no one knew why. If I somehow manage to travel back to my timeline, I'll search for the answer to this, he resolved.
He stared into the fire, thinking again about how he had ended up in this place and whether it was some form of karma or something else entirely. After a long sigh, he thought, I know it won't be easy, but I have to try at least. If I somehow manage to create a better place to live... man...
Halting his daydreaming, he resumed reading. The text provided a quick overview of metric scales, from nano to giga, and explained a bit about the history of how a meter was created and defined.
[You've probably already noticed how these definitions started out completely useless to you. Luckily, we noticed that too, and so we have printed a handy 10cm ruler in this section(...)]
On a sidebar, there was a 10 cm ruler and a printed protractor. "Now that's convenient," Rafael noted, impressed by the practical inclusion.
[The only major unit left for you to define is time, which is based on the second.]
Wait, wait, is it going to say how to measure a second?! Rafael's eyes widened with anticipation as he continued reading.
[To produce a device that can indicate one second without requiring cesium 133, you'll need to construct a simple harmonic isolator, which means "tie a rock to a string".]
"Let's gooo!" Rafael shouted, punching the air in triumph. But then he quickly covered his mouth and lowered his head and arm. Shit, hope no one heard that, he thought, embarrassed by his outburst.
To measure a second, he would need to tie a rock onto a 99.4 cm long rope, creating a pendulum. The book explained that when the length was exactly that, no matter the weight of the rock or how far back you pulled it before letting it drop, the time it took to swing from one end to the other would always be 1 second.
The next paragraph explained that to measure one liter, you'd just need a cube 10 cm wide on each side, and having a liter of water also meant having 1 kg of weight. For sound, you'll want to measure frequency, which is simply the number of vibrations per second.
A hertz (or "Hz" for short) is one complete cycle per second. For physics, the amount of force required to accelerate a 1 kg mass by 1 meter per second squared is called a "newton," the amount of energy transferred to that object over 1 meter is called a "joule," and a watt is simply one joule per second.
Wow, calm down, book, too fast, Rafael thought, feeling a bit overwhelmed by the influx of information. Jokes aside, there is so much in here that I think people won't believe me if I just say that I invented and thought about all this alone.
Maybe if I say that half of it I learned from somewhere else... No, my background story is that I forgot everything. Aaaah, I'll figure something out in the future.