We explored the impact of ossification fluid on violin timbre. Now is the time to unravel the specific formula of the ossification fluid. We have demonstrated through analysis of the chemical composition of the ossified soundboard that the substance contains a large amount of silicon dioxide and potassium. This fully demonstrates that ossification fluid is a substance similar to glass, more precisely potassium silicate and calcium. In ancient times, craftsmen melted silica, charcoal, and potassium hydroxide in sealed crucibles to obtain potassium silicate and calcium. Potassium hydroxide can be extracted by burning charcoal from growing green grape vines, and the carbon effect is better with squeezed grape pomace. Carbon, silica, and charcoal are all very brittle. Crush them and dissolve them in boiling water. Boil the solution again to make it thick, then precipitate and pour out the clean solution to obtain a colorless ossification liquid. When the liquid is applied to the soundboard, it appears yellow green, and after oxidation, it turns into a beautiful golden cinnamon color. When the liquid is too thick, it must be dissolved in water to the desired consistency before use, but the effect is better when the liquid is still fresh. In fact, if it is too thick or left for a long time, the substance will become difficult to hydrolyze and produce many clumps. Therefore, it is best to drop a drop on oil-free glass before use. If the liquid is white and opaque, it cannot be used, just as transparent as glass. In ancient times, this mixture was used in surgical procedures to harden bones; In modern times, people in rural areas often use it to coat eggshells for preservation purposes. The viscosity of this potassium calcium silicate solution must be adjusted properly to allow the liquid to penetrate the wood well and coat the fibers of the soundboard pores, but it cannot block the pores due to being too thick. The surface of the processed soundboard will become rough, and can be polished with fine fish skin and goose grass powder. Under oblique illumination, with a magnifying glass, we can see small and beautiful lines and spots in the grooves under the coating. The polishing process needs to be very careful to avoid surface abrasion. This important process can be replaced by wiping with a cloth dipped in water once or twice. Potassium will dissolve, but silicon has already combined with wood fibers. This coating is of great significance to the subsequent paint, as the paint will adhere to it but never penetrate into the wood. A molten layer is formed between the wood and the ossified coating, and between the ossified layer and the paint layer, the paint only tightly grasps the ossified wood pores and adheres to the surface of the soundboard rather than penetrating into the wood. We can see clearly with a magnifying glass, and even with the naked eye, I can see the stretched ossification layers between the wood fibers. I came to realize the above facts through the following two observations. We see that the paint film of all the old pianos has been worn off, but there are still a few spots of paint remaining at the pores. In addition, the paint film at the cut part of the wood fiber is even preserved intact. In order to explore the material composition of ancient paint, I set aside the viewpoints and ideas of modern and passed down old formulas and sought answers from Lao Qin. The first impression a Stradivarius gives is that it is so soft and gorgeous, very rich in oil and wax. If it is really oily, then it should not only deeply penetrate the wooden soundboard on the surface. This impression arises from people's awareness of the changes in wood grain caused by the reflection of light from different angles on the paint layer.