In the autumn of this year, the Khitan lord Abaoji also died of illness, and with the support of the Empress Dowager Shulu, the second son Yelu Deguang crossed the eldest son "Human Emperor" Yelu Bei and became the new Khitan lord. It's just that due to internal instability, the ambitious Yelu Deguang has no plans to "go south to herd horses" for the time being.

Because the general Yuan Xingqin and Li Siyuan had a "grudge against killing their sons", in order to avoid giving Li Siyuan an excuse to send troops to fight, Li Qi recalled Yuan Xingqin back to Jinyang, and reassigned the general Zhang Jingda to stay behind Tonghua to guard Tongguan.

Fortunately, the Gujiao Iron Mill gradually mastered the smelting technology of spring steel in the steelmaking furnace using the churning method, and a furnace of spring steel can be smelted every few furnaces, although it is a bit like a pump, which is not very accurate.

With spring steel, Wang Mao, the head craftsman of the blacksmith workshop, took it upon himself to work in the blacksmith workshop for two days before he was able to create two steel crossbows of the kind that Li Qi requested. The crossbow is a powerful thing with strong penetration power. Since it can only shoot straight ahead, its range can only be within eighty paces, and its attack range and rate of fire are far inferior to those of the bow.

In the Tang Dynasty, the manufacturing technology of the crossbow was very mature, and it was divided into many types such as hand crossbows, stepping crossbows and bed crossbows. The steel crossbow made by the ancient Jiao Iron Workshop is similar to the Song Dynasty divine arm crossbow, and the change that Li Qi made for this hand-held crossbow is that the grip is no longer a straight square log, but is made into a shape similar to the butt of a later gun. This shape is more ergonomic, making it more stable when aiming and firing with a crossbow.

It's just that the shape of the crossbow is large, and it is very inconvenient to carry it in normal times.

Yuan Xingqin told him that it was much more convenient for cavalrymen to use a bow than a crossbow. And in Jinyang, a good iron tire bow can be sold for more than ten times.

Li Qi thought he had a point, so he followed his suggestion and let the craftsmen use the remaining spring steel to make riding bows after transporting the remaining spring steel back to Tang Ming Manor.

This is mainly for the sake of Brother Kong Fang's face.

The production of the bow is very complicated, mainly because it is not easy to shape the dry material of the bow body.

Unlike the southerners, who mostly use bamboo as bow tires, the northerners mostly use hardwood as the main material of the bow body.

The ancient Chinese recurve bow production process is very complex, it is a composite bow formed by a variety of materials bonded, and the main materials used are dry, angle, tendon, silk, glue, lacquer, which are collectively called "six materials".

Generally speaking, the standard of dry material of the bow body is that the top wood, the Italian wood, the oak wood is secondary, and the bamboo is the bottom. However, it is suitable for making a bow body, and it is very rare to have excellent elasticity and toughness.

It takes several months to make a bow from hardwood, but if you use spring steel, it saves a lot of time. Moreover, the strength and toughness of steel are far superior to that of wood, and the so-called iron tire bow in ancient times is precious, mainly because spring steel is very rare.

Now, the ironwork workshop of Gujiao has no such trouble.

And due to the application of hydraulic forging hammer, not only the production efficiency has been greatly improved, but also the quality of the bow body made of spring steel is quite good.

After the bow tire is made, all that remains is to stick the corners and apply the tendons. Horns, i.e., the horns of cattle and sheep, etc. The horns are cut open, then cut into long strip-shaped slices, and pasted on the inside of the bow tire with bladder glue. The glue is made of animal skin glue and fish fat, among which fish maw glue is the best. The tendons are made of filaments made from the ligaments of animals, among which the cow back tendons are the most preferable. The rib wire is also pasted on the back of the bow tire, that is, the outside. Silk is silk, which is mainly used to tightly wrap the bow body that has been preliminarily made by the corner tendons to make it stronger and tougher.

The process of making a bow is very complicated, and if it is a wooden bow, the whole process takes at least a year to complete, which is similar to the process of making a luthier in later generations. On the other hand, the process of making a good bow is longer, even taking two to three years to complete.

This is mainly because the main elasticity of the wooden bow comes from the tendons and horns.

The use of spring steel as the bow body itself has strong elasticity, and the strength and hardness of the steel bow itself is much higher than that of a wooden bow. However, since the two processes of tendon application and corner sticking still take nearly two months, it still takes three months for a steel bow to be completed.

However, the use of spring steel to make steel bows is also a major product of the Tang Ming Manor Iron Workshop.

When the craftsmen were looking for ore in Gujiao, they actually found a pyrite vein.

This pyrite was called fake gold by the ancients, and no one knows what it is used for except to deceive people. Except for some of the ore that crystallized better, which was polished into ornaments, most of the pyrite was thrown away as scrap.

This thing really can't make iron when thrown into an iron-making furnace.

It's just that Li Qi knew that in later generations, most of the domestic sulfuric acid production relied on calcined pyrite as the main raw material. Pyrite is ground into powder, and then put into a calciner similar to a lime kiln for heating and roasting, a large amount of sulfur dioxide will be produced, and sulfur dioxide vapor is then secondary oxidized through the lead chamber to make an aqueous solution of sulfur trioxide, which is sulfuric acid.

How do you build a lead room?

This is indeed a big problem, but it is not a problem that Li Jiqi is thinking about now.

He now has his eye on another product in the process of making acid from pyrite - ferric oxide.

This thing is one of the main pigments commonly known as "iron red".

With it, Li Qi was able to dye the lifeless gray-and-white tweed cloth that was now spun from wool in the workshop of Tang Ming Manor with bright colors.

It seems that dilute sulfuric acid can also treat wool and woolen cloth and play a certain role in bleaching......

Because there is a lot of wool in the north, and it is also very cheap, the weaving workshops of several royal estates in Jinyang are now very prosperous, and the crimson cloth woven and dyed has become one of the most sought-after goods for caravans on the grassland. The construction of barrages and dams is a major event that benefits the country and the people, and it is also a great opportunity to become famous in the world in one fell swoop. After several dams were built and reservoirs began to store water, coupled with some water conservancy and irrigation facilities planned to be built, most of the farmland in several estates could be irrigated, and there was also wealth, and this change alone was enough to feed more than 100,000 people around Jinyang City.

Inspecting these barrage dams under construction and the attached water conservancy facilities and hydraulic workshops can indeed make Li Qi feel a great sense of accomplishment from the bottom of his heart.

It's a good start.

He felt that since he had come to this world, he had an obligation to spread the seeds of industrial civilization in this world. Only after entering the industrial age will the ancient Chinese civilization become stronger and stronger in this world, and no longer suffer from the great destruction from the barbarian tribes.