Although it was cool to bombard people with artillery, Marin found a problem - the 50 Furlong rear-loading bronze cannons captured from the army of the Electorate of Saxony were not uniform......

Of the 50 Furlong guns, some were 2-pounderers, some were three-pounderers, and some were 4-pounderers, with mixed calibers. Moreover, even if the same caliber, there are slight differences because of the casting process.

Therefore, if you are fighting with a captured Fran cannon, you will need to make matching ammunition. Fortunately, it is not difficult to cast shells, as long as there is a template shell with a high degree of fit, you can use the sand turning method to cast exactly the same shell. Although there must be some honeycomb in the shells cast in the wet sand because of the water vapor, because they are cannonballs, not barrels, it has no effect. Anyway, it is used to smash people, and the iron ball shell has a honeycomb, which is definitely harder than the human body. If you smash it, you must be finished......

And, to Marin's surprise, according to the confessions of the captured Saxon artillerymen - the artillery of the Saxons, a lot of them were made of stone balls, not iron balls. Because of the current backward iron smelting technology in Europe, most blacksmiths still use the direct reduction method of putting iron ore on a red-hot charcoal fire to smelt iron. Therefore, the price of iron in Europe is still very expensive at the moment. Therefore, it is also good to be able to use stone cannonballs instead of iron ball cannonballs......

"Stone cannonballs...... It doesn't seem to be powerful enough, and it can't hit the city wall......" Marin muttered.

However, soon, he reacted - infantry artillery is to hit people, not siege cities, it doesn't have to be iron balls, stone bullets are definitely enough.

However, for Marin, the production of stone shells is more troublesome than the production of iron ball shells. To produce iron ball shells, you can quickly cast shells of the same size by pressing out space in the two halves of the sand box with a model standard shell, then separating the two halves of the sand box, and then putting them together and pouring molten iron from the casting hole above.

If you use stone bullets, you need to use a stonemason to polish them by hand. Although the stonemason can also polish the stone projectile to the exact same size as the iron ball cannonball, it is very time-consuming and not as fast as the sand casting method. Other countries use stone bullets because iron balls are too expensive, but Marin doesn't care...... He had an iron-making blast furnace, used coke to smelt iron, and imported hematite from Luxembourg to smelt iron, and there was a lot of molten iron. Therefore, he does not care about the cost of iron balls. Moreover, polishing stone ball shells is too time-consuming and inefficient. Therefore, Marin still intends to use mainly iron ball shells.

However, one day, after seeing workers building concrete roads in the city, Marin immediately changed his mind......

Why? Because Marin came up with the idea of pouring shells with cement......

Yes, cement-poured shells. Stone shells are difficult to polish because they require a stonemason and take a lot of time. With cement, it's easier.

After thinking about it, Marin felt that it was possible to make two iron bowls that could be put together. Then, put the mixed cement into an iron bowl. After a while, when the cement ball can not fall apart, separate the iron bowls on both sides, and take out the cement ball to air dry or sun-dry. Then, a cement ball cannonball was born......

It is indeed a waste of infantry artillery to use iron balls to beat people. Anyway, it's a smashing person, and the difference between an iron ball and a cement ball is not very big. Moreover, how cheap are cement balls? It's easy to pour, and you can save a lot of money compared to using iron balls......

As soon as he thought of it, Marin immediately found a craftsman to first cast an iron bowl divided into two halves, which was specially used to pour cement ball shells. However, it seems that the processing of iron bowls is somewhat difficult, after all, it is an iron thing, and the mold is troublesome.

Later, a craftsman simply proposed that it would be better to use a wooden bowl...... Wooden bowls can also shape cement, and moreover, it is easy to process wooden bowls, and carpenters can fine-tune them at any time. Unlike iron bowls, if the casting fails, it is very difficult to modify. As for the wooden bowl, the carpenter can adjust it after a while of hammering with an axe and chisel. If it really doesn't work, just change it to a wooden bowl, and the wood is worthless......

After several days of fighting, a method of fixing concrete-poured shells with two hemispherical wooden bowls was developed......

As long as there is cement, pouring cement ball shells should not be too simple - pour cement directly into the bowl, and the two hemispheres will force together to squeeze out the excess cement. Then wait for an hour or two, and the cement in the bowl is almost not easy to fall apart, and then remove the two halves of the wooden bowl so that the cement ball is exposed to the sun or dried in the sun or air-dried...... A cement ball cannonball is done......

After the cement ball is dry and hardened, after testing, it is not particularly different from the stone shell. Anyway, it's enough to beat people. After all, if the human body collides with the cement ball, it must be the human body that suffers. Even if the cement ball is smashed, it is nothing, after all, cement is not valuable, and it is no big deal to get a few new ones. Even if you smash the gap, it's nothing, get some cement and paste the notched part, and it can continue to be used as a cannonball after it is dried. But people are different, they are hit by cement ball shells, they are either dead or disabled, and it is useless to wear plate armor. That kind of kinetic energy, even if it can't smash through the plate armor, can break your bones and make you die in pieces.

Marin summoned his men and showed them the low-cost cement ball cannonballs. As Chancellor of the Exchequer, Kohler fell in love with this low-cost cannonball at a glance. As Marin's henchman, Kohler knows very well how low the cost of cement is. At least, much lower than the iron ball. This is because to make iron balls, hematite needs to be imported from Luxembourg and then smelted into molten iron through the equipment of the steel mill and craftsmen. Finally, it is cast one by one by a craftsman who turns the sand casting. The cost of a series of shells is much higher than that of cement shells.

And what about the cement ball shells? Just find a construction worker, stir the cement, and then take out the mold wooden bowl, no craftsman is needed, ordinary construction workers can produce this kind of cannonball, it is extremely simple.

Although Marin said that the bombardment of the city walls and the artillery battle at sea still require the use of iron balls. However, switching to cement ball shells for infantry artillery will definitely save a lot of money. For Chancellor of the Exchequer Kohler, nothing is more important than saving money.

As for the problem that the cement ball cannonball shell is easy to cripple when bumped, just like Marin planned before - bring a few construction workers with the army, and bring a little cement yellow sand. If there is a gap in the recovered cement ball shell, stir some cement and smear it on the gap of the shell, dry it, blow it, and a new infantry shell will be baked again......

Marin was so proud of his original invention that it seemed that there had never been a cement cannonball in history......

It's no wonder, though. Because, when cement appeared (19th century), solid shells had been eliminated, and it was already the world of flowering shells. So, naturally, no one thought about pouring shells with cement. After all, cement can be made into solid shells like stone ball shells at most, not flowering shells.

Therefore, the cement ball cannonball made by Marin is really original. Moreover, because there is no cement in other countries, if you want to copycat, you must first master cement technology......