"Zhuangzi" says, "When wood touches each other, it will happen." I rubbed two pieces of wood against each other. They generated only a slight temperature, but it was impossible to burn them. The ancients used sandalwood to make a flywheel, set it on a horizontal axis, and crank the handle to rotate quickly. Then touch the edge of the wheel with a dry locust wood stick, which will soon smoke and burn. Zheng Xuan's annotation "Zhou Li? 6? 1 Xia Guan? 6? 1 Si?" leads people to say "the fire of locust sandalwood is taken in winter", which is how it was taken. These two methods are also.
The third method is to use Yang Sui to make fire, see Cui Bao's "Ancient and Modern Notes". The Yangsui is a concave bronze mirror shaped like a cup and saucer. It faces the sun and focuses on moxa, which quickly ignites. The fourth method is to use a crystal ball to make fire. "Old Book of Tang Dynasty" says: "The Rakshasa Kingdom produces fire beads, which look like water essences. At noon, the beads bear the shadow, and if you take moxa and hold it, the fire will come out." The ancient Rakshasa Kingdom was in today's India. The fire bead is a crystal ball, which is used as a convex lens to focus the burning moxa, the same as the Yang Sui. The fifth method is strange, using ice to make fire. There is an ancient book that says, "Cut ice to make it round." Fire is like a convex lens that focuses sunlight. It's a pity that I don't know how to cut the ice. Don't think that primitive people are stupid. They know how to use local materials and reduce costs to a minimum. The Sixth Method was to make fire by striking flints, which later evolved into lighters.
However, what amazed me the most was the seventh method. A low-educated gentleman who was released from prison told me that he used a bamboo chopstick, wrapped it in bed straw, stepped on plastic soles, and rolled it back and forth on the rough cement floor. Always step on it tightly to ensure that the fire will occur within three minutes. He said: "Smoking in prison is how you make fire." This is really a modern Suiren, I admire him. I also want to say how smart working people are, but I finally feel it is inappropriate. The prison has prison regulations, and Suiren's family is not allowed to make fire randomly.