How to Invent Everything

if at this point you’re thinking you could easily improve this system by farming only half your fields each year while the other half recover, congratulations: you just invented crop rotation!
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locks in 0 degrees as the temperature of a weird slurry of ice, water, and salt that Mr. Fahrenheit threw together before calling it a day, and we will discuss it no further,

. All you need is this book and some water.