Zheng Hui hurriedly replied: "The prince is wise, the prince found such a rich land for the Han people, it can be said that he is an immortal hero of my Han people, a heroic hero." ”

Li Zhi laughed, pointed to the west and said, "This Australia is not only a rich land, but also a resource-rich mining area. There are abundant metal deposits here, and in the future, it can become a large rear base of our one town and nine provinces. ”

Australia is one of the world's most famous mining regions. It accounts for one-tenth of the world's iron and copper ore, and one-third of the world's aluminum.

Many of Australia's minerals are located close to the sea, and can be transported to Tianjin by ship after a short distance on the road. In this way, the freight is very low, after all, a ship with dozens of sailors can complete the transportation of hundreds of tons of ore in ten days.

Shipping ore from Australia is cheaper than hauling ore by horse-drawn cart from the interior of Daming.

Cheap raw materials are very important for industry. The essence of industry is to turn raw materials into industrial products, if the price of raw materials is low, the production cost of products is low, then enterprises can greatly reduce the price of products. After the price of the product is reduced, the demand for the product will rise sharply in the whole society.

With cheap raw materials, the industry will expand violently like a shot in the arm.

Gao Ligong said: "Lord Wang, this Australia is occupied by us, and if we find minerals here, it will be much more reliable than the mines in Shanxi and Mongolia." ”

Li Zhi nodded, waved his hand and pointed ahead, and said, "Go!" Let's go over there! ”

####

On the fourth day of July, Li Zhi had just returned to Tianjin from Australia and had started work before he had a few days off.

The first thing Li Zhi wanted to look at was the newly produced rear-loading artillery from the artillery factory.

After Li Zhi designed the Jinwang rear-loading rifle, the design of this new rifle gave great inspiration to the craftsmen of the arsenal. Rear-loading greatly increased the rate of fire and improved the rifle's battlefield adaptability, which was a novelty for gunsmiths.

Inspired by this, Cao Yu, the chief manager of the arsenal, led the gunsmiths to tackle key problems. Cao Yu was originally a gunsmith and was very good at casting artillery. After a few years, now they have managed to design a breech-loading gun.

Cao Yu's new artillery was placed on the training ground, Li Zhi looked at the gun body and asked, "How did this gun achieve rear loading?" ”

Cao Yu bent down and pointed to the back of the barrel and said, "Lord Wang, look, the back of the barrel is open, and the hole in the entire barrel is exposed. Our soldiers, if they want to load, only need to load the shells and fanny packs from the tail of the barrel into the bottom of the cannon. ”

Li Zhi looked at the tail of the round hole, nodded, and asked, "Then how did you close the artillery?" ”

Cao Yu lifted a rather complicated-looking iron-handle-shaped bolt from the ground, and said to Li Zhi: "Lord, you see, we used this bolt to insert this bolt into this hole on the side of the cannon tail to achieve breath-holding. ”

Li Zhi took a closer look at the bolt.

The bolt was made of copper, not a regular rectangle, but an irregular trapezoidal shape. The front of the bolt inserted into the tail of the gun is completely perpendicular to the hole at 90 degrees, but the back of the bolt is angled.

"Look, lord!"

Cao Yu inserted the bolt into a hole on the side of the bottom of the gun. As soon as it is rotated, the caliper of the bolt gets stuck in the inside of the hole. Then he began to turn the large handle on the top of the bolt, separating the main part of the bolt from the caliper of the bolt, and pressing the body of the bolt into the depths of the hole.

Since the back of the bolt body is slanted, the more the bolt body is pressed into the inside of the hole, the greater the pressure will be generated between the back side and the inner wall of the hole, pressing the front of the bolt tightly against the bottom of the barrel.

As a result, the rear part of the barrel was sealed with a clamping bolt.

Copper is a metal that is quite elastic. Although the force of manpower on the handle is not large, it is converted by the principle of leverage, and the force acting on the bolt is very huge, which is enough to firmly press the bolt at the bottom of the barrel.

With this sealing method, the force acting on the bolt when the cannon fires does not eject the bolt. Because the force generated by the expansion force of the propellant acts directly to the back, and the bolt is inserted from the side and pressed tightly into the hole, the force of the backward pressure is perpendicular to the direction of the insertion and exit of the bolt.

This sealing method is the same principle as the sealing method of the Krupp rear-loading gun in the late nineteenth century. It is a little more ingenious than the British Armstrong rear-loading gun, and it is also a little less difficult to machine.

Of course, the actual Krupp gun has a higher level of technology, and the structure of the bolt is more complicated. Li Zhi felt that with the current industrial level of Tianjin, it was not yet mature to develop the Krupp artillery.

With Cao Yu's simple sealing method, the rear-loading gun can achieve a considerable degree of sealing.

The development of rear-loading guns is also progressing gradually, not overnight. In fact, the Furlong cannon widely used in the late Ming Dynasty was also a very practical rear-loading gun, of course, this kind of cannon had poor sealing and limited firing range.

Li Zhi nodded again and asked, "How do you shoot it?" “

Cao Yu pointed to a small hole in the tail of the cannon and said, "We still use the Thunder Acid Gong as the firing medicine." We made a cartridge of thundermercury and black powder. When firing, this cartridge is inserted into the firing hole, and as soon as the firing rope is pulled, the thunder mercury ignites the black powder, and the propellant in the barrel is ignited. ”

Li Zhi waved his hand and said, "Try to shoot a shot!" “

Cao Yu shouted the order, and together with several artillerymen, he opened the barrel of the cannon and stuffed the conical lead bullet and the bagged black powder into the tail of the gun. Then Cao Yu inserted the bolt into the hole in the tail of the gun, and rotated the handle to seal the tail of the gun. At the same time, another gunner loaded the firing powder cartridge.

"Three!"

"Two!"

"One!"

"Fire!"

With a "boom", the small cannon spewed out tongues of fire towards the target area. The tail of the cannon spewed out huge white smoke, which greatly hindered Li Zhi's vision.

Li Zhi took a few steps to the side, looked through the smoke, and found that the target a hundred meters away had been knocked down.

Li Zhi said: "Try to hit a farther target!" “

Cao Yu and the gunners hurriedly adjusted the muzzle of the gun and began to load the ammunition again.

With the cooperation of three gunners, the six-pounder cannon can be reloaded about every fifteen seconds, which is significantly faster than the front-loading gun.

The artillery fired at targets farther away, and the hit rate was quite impressive. This rear-loading gun is also rifled inside, and there are no problems with accuracy. It can hit targets up to three miles away.

Li Zhi observed the rear-loading cannon and pondered for a while.

"Some air leaks..."

Cao Yu touched his head and said, "Lord Wang, there is more or less a little air leakage, but we will find a way to improve it." “

Li Zhi said: "But you can load this kind of cannon on the tank first." Our tanks do not yet have offensive weapons, and we urgently need your rear-loading guns. “

Cao Yu's eyes lit up when he heard this.

"Lord Wang, so our rear-loading cannon can be used?"

Li Zhi smiled and said, "It's barely usable, let's make do with it first." It's called Cao's rear-loading gun. “

"The craftsmen who participated in the development were each rewarded with one hundred taels of silver. The leader will be rewarded with two hundred taels. Cao Yu rewarded five hundred taels. If the airtightness is improved in the future, there will be more rewards! “