After the Frost Descent, one can see the following phenomena when going out in the morning and evening: a layer of water droplets on the roof of cars downstairs, shoes getting wet when stepping on the grass, and even the balcony railings feeling sticky to the touch. Old people who get up early to take a walk know that dew comes and goes at will in this season, being thickest around dawn, and disappearing completely once the sun rises high in the sky. The sleepers beside the railway also experience this. Covered in dew in the morning, they are dry and refreshing at noon, only to be covered again the next morning.
Dew and frost are siblings, both condensed from water vapor when it encounters cool objects. In this season, the temperature difference between day and night widens. During the day, the sun still warms the air, but as soon as it sets, the cool air settles close to the ground, cooling things faster than the air. Water vapor condenses as soon as it touches it. At night, it's not too cold, so what condenses is dew. As you step further into the cold, dew turns into frost, a white layer that becomes more pronounced at dawn. The interesting thing about frost is that when it hangs on your body, it looks like dry powder. When the sun comes out, it melts and turns back into water. It's like this layer of dampness is saved for the morning. The solar term of Frost Descent talks about this hurdle. From now on, everything left outdoors will have some water on it, and it won't fail every day.
Wood that has been exposed to water sounds untrustworthy. Who hasn't seen the state of the wooden stakes in our old courtyard and the planks under the windowsill after a few rainstorms? Water seeps into the wood along the grain, causing the color to become darker or lighter in patches. The grain swells, giving a rough feel. Over time, the texture inside gradually changes, and a pit appears when you scratch it. This is the natural soft spot of wood, which absorbs water silently.
The wooden sleeper also has the same grain pattern, with fine cracks running one after another. It should be the most absorbent. But even if dew lies on it for a whole night, it doesn't really penetrate deep. The water droplets cling to the surface, wandering along the grain patterns, searching all night but finding no entry. The dew is not deep, just a thin layer, but it comes every day and is the best at wearing away. As soon as the sun comes out, it dries up, and the water has come for nothing.
The confidence lies within. Back then, during the oil impregnation process, the oil penetrated into every tiny crevice of the wood. Oil, once in, never leaves. It stays for decades, more attached to its home than anyone else. The interior is filled with it. Water, by nature, seeks out cracks to penetrate, but there's no place for it in the crevices. After circling the door, it finds someone living inside, so it can only wait outside. By noon, when the sun shines, it tidies up and leaves.
This season is the time of the year when water vapor is most prevalent. Summer rain is like a downpour, coming in bursts and stopping intermittently. It may be fierce, but at least there are moments of respite. Autumn dew is like a drizzle, not much in quantity, but it persists daily, arriving morning and evening, like a set alarm clock. For an ordinary piece of wood, enduring this constant dampness is the hardest. For sleepers, there are countless ways to get wet, but the outcome is the same: you can go out and about, but don't even think about getting inside. This ordeal, it can withstand.
Not only are they scattered along this row in the wilderness. Those densely paved beside the switch, those rolled back and forth by mining cars on the mining tracks, and those lying in the freight yard beside the platform, all are the same wood, in the same situation. As the weather turns cold, dew doesn't discriminate; it hangs wherever it is placed. These woods are not in a hurry, each with oil in its crevices, each guarding its own territory. When the oil entered this layer back then, everything was already arranged.
In the days following the Frost Descent, the dew became thicker day by day, and frost came one after another. They all traveled back and forth on the wooden sleepers, and for decades, they had not gained any advantage.
Tomorrow morning, when I pass by the railway, the dew on the grass blades will be thick, and there will also be a layer on the sleepers. Don't worry about it, because the sun will come out and it will disappear. It has long been familiar with the rules of dew.
