How to Invent Everything: A Survival Guide for the Stranded Time Traveler

by Ryan North

CIVILIZATION PRO TIP: There are downsides to building the foundations of modern science and measurement around the mass of an old hunk of metal in a jar in France.

A rock tied to a string that can swing freely is called a pendulum, and it turns out that one second is the time it takes any pendulum on Earth—regardless of weight—to swing from one end to the other, as long as the pendulum is 99.4cm long. This cool property of pendulums—that they always take just about the same amount of time to complete a swing no matter how far back you pull the weight before letting it drop—makes this a particularly easy experiment to perform. This property was discovered by a guy named Galileo Galilei in 1602, but you’re going to take the credit. It’s your property now.

You might think, “Oh, I’m trapped in the past, time to kill a lion and do that thing where you skin it and then put its head on top of your head so you can wear a lion’s head like a hat.” This is a bad idea. Without tanning, animal skins quickly rot, and even dried ones become hard, inflexible, and brittle. Tanning transforms these skins into leather: a substance so resistant to rot that leather shoes from 3500 BCE have survived into the modern era. It’s something you’ll definitely want to do, but you should keep in mind that preparing animal skins for tanning involves not only skin fermentation but also soaking them in urine and massaging them in poop slurries, so maybe set up your tanneries downwind.

Anyway, enjoy the fun and practical technologies of leather and rawhide and try to forget the part where you splashed around in watered-down poop.

Finally, we should stress that none of the techniques in this table protect against sexually transmitted infections, which you’ll need to watch out for. Syphilis, in particular, should be avoided: it has much more awful strains that died out before the modern era. When it first appeared, syphilis sufferers would be horrified as their entire bodies became covered in pustules, and that was before the flesh would fall from their faces.* Penicillin (Section 10.3.1) is an effective syphilis cure, though in our timeline we only found that out centuries after the “face-fall-off” variant had died out.

You can get other colors from biological sources, and ground-up insects, mollusks, and even dried-out poops have been used in the past. It’s very easy to go too far: a shade of yellow called “Indian yellow” was once made by feeding cows only mango leaves until they were so malnourished their urine turned a bright yellow, and a favorite shade in 1600s CE Europe called “mummy brown” was made by grinding up ancient mummies (feline and, yes, human) to paint with their remains.

You can reinvent modern music by simply humming a song you remember, and when you’re done, announcing, “That composition is called Salt-N-Pepa’s ‘Shoop,’ and I just invented it”—we do, in fact, recommend you do exactly this—but later on we’ll be providing snippets of written music for you to preemptively plagiarize, so we need to teach you how to turn those written symbols into song.

Honey absorbs water so readily that any bacteria that attempt to colonize it have the water sucked out of their cells, thereby killing them.

That’s why there can’t be a single objectively perfect song, but there can still be one perfect song for you. That song? We can’t say for sure, but there’s a nonzero chance it could be “Shoop” by Salt-N-Pepa. Hey. Give it a chance.