Purchase of sodium ferrocyanide
At some point, there was a spread of sodium ferrocyanide in the city, and it was widely used. I heard about it, and I longed for it, and wanted to buy it and use it.

So I traveled to all the city shops, looking for grocery stores and medicine stone stores, but I couldn't find it. I was worried, I was afraid I wouldn't be able to find this treasure.

And those who asked all the merchants, all shook their heads in ignorance. Suddenly I recalled that there was a Jia person in the city who was good at seeking strange goods, so I visited him.

When I went there, I saw Jia people were busy. Yu Zhiqian, bowed and asked, "Dare to ask you if you know where to get sodium ferrocyanide?" Jia pondered for a moment, and said, "This product is rare, but I have a way to make it happen recently." Yu Daxi said, "I wish you help me, and I wish you a generous reward."

Jia nodded and told Yu to wait for a while. A few days later, Jia sent a boy to inform him that sodium ferrocyanide had arrived. Yu was in a hurry to get it, and when he saw it, it was pure in color and luster, and his heart was very happy. He paid a reward and brought it back with him for later use. Since then, he has obtained this sodium ferrocyanide, and he is satisfied, and he will use it to develop its effect.