The matter of lead vinegar and hydrogen sulfide
In the past, I was a scholar, and I was good at the art of checking things. One day, I took the liquid of lead vinegar and placed it in an open vessel. Then, there was hydrogen sulfide gas, quietly entering it.

But seeing the two meet, in an instant, the liquid of lead vinegar gradually changed. There was a black thing in the liquid, which slowly precipitated, like ink dyed in water, gradually diffused. This is the reason why lead vinegar and hydrogen sulfide combine.

Lead vinegar has a peaceful nature, while the gas of hydrogen sulfide has a pungent smell and is also lively. When the two meet, they react. Lead ions combine with sulfur ions to form black lead sulfide. Its appearance is also, black and delicate, sunk at the bottom of the tool, like night falling, with a deep ink color.

The wonder of this change is not only a wonder visible to the naked eye, but also related to the principle of knowledge through matter. When a scholar sees this, he realizes the wonder of the symmetry of matter. Everything in the world interacts with each other and changes endlessly. The encounter between lead vinegar and hydrogen sulfide is just one example. Looking at this tiny change, it can be deduced to the mystery of the sympathies of all things. The reason why this scholar is tireless.