However, after seeing the real 'helmet dog', Liu Jingtian has a little idea for the next battle:

"If your body temperature is so high, you're afraid of the cold! It seems that there is an easier way to deal with it...... Besides, this thing is sensitive to magic! It can be used as bait...... The old man had an immature idea......"

The Great Demon King is brewing a conspiracy......

On the other side, the dungeon upstream. Pen ~ fun ~ pavilion www.biquge.info

Although mining has been temporarily stopped, everyone has collected a lot of pyrite that is shiny like gold.

However, this kind of iron ore can hardly be regarded as 'iron' ore in the earth plane, and has no smelting value, and is more used to prepare sulfuric acid.

Anyone who knows a little about heavy industry knows that in iron ore, the most hated are sulfur and phosphorus, which will make the product brittle and easy to rust, and at the same time, the smelting cost of iron ore with high impurities is also very high.

But the current kobold has no picky capital, so he can only bite the bullet. It just so happened that in the dark world before, everyone was also very short of sulfur, and as a result, Guan Renxiu came up with a very troublesome 'pyrite sulfur project', and the photochemical equation could be listed six or seven.

But Kwan Renxiu's process was really troublesome—it required a lot of clay pots and pipes, and the pipes were a dizzying mess, plus a series of heating processes...... As a result, the production of sulfur and iron oxide is still very small, and it is simply calculated in kilograms.

Looking at hundreds or thousands of tons of ore, Liu Jingtian said that the pressure is not great: if there are too many dogs, it is willful! Just open a few more production lines!

Doghead Waterfall Sweat ...... How many clay jars and clay pipes have to be burned!

Here's a little more verbose of Kwan Renxiu's method for junior high school students:

1. Pyrite to sulfuric acid

2. Dilute sulfuric acid and pyrite produce hydrogen sulfide and iron sulfate

3. Pyrite is heated with water to produce sulfur dioxide and iron oxide

4. Sulfur dioxide reacts with hydrogen sulfide to form elemental sulfur

Just looking at this chemical reaction process, you can see that it is simply a high-tech fancy dog abuse.

So, under the command of a small number of kobold intellectuals - primary school education - kobold began to spontaneously improve the craft.

Count them lucky, and by mistake, they found several simple pyrite smelting methods-

The easiest way to do this is to calcined it in the open air, which produces iron oxide and a very pleasant-smelling sulphur dioxide gas...... The yellow smoke is billowing out, those who see it hurt their eyes, and those who hear it cry.

Then this method was decisively killed by Liu Jingtian: Stop, the leaves of my farmland are all yellow! You are artificially creating acid rain!

Well, by mistake, another method was found - pyrite was ground into powder, and then a huge amount of toner was added, and then heated in a closed container, and iron oxide, sulfur, and carbon dioxide were directly obtained, and then according to the difference in weight, water was used to screen it......

And this method, the iron oxide obtained still contains a bit more sulfur, it doesn't matter, everyone runs a little farther, continue to calcine iron ore, and make yellow smoke!

Liu Jingtian said: This time it is not only polluting the air, but also polluting the river...... Forget it, I don't know, anyway, no one will be fined if it's far away......

In this way, stumbling, the kobold finally put the steel production that had been suspended for a long time into operation, and the gun factory, which had not been in operation for a long time, began to build cannons in full swing again......

The main force of production this time is mainly the twelve-pounder cannon and the eighteen-pounder cannon, and the six-pounder cannon and mortar cannon are completely discontinued - the former has been decided to replace it with a 'torsion compound bow double crossbow', and the latter can be replaced by a counterweight catapult.

The Twelve-pounder was already very mature in the dark world before it. And the design of the eighteen-pounder gun did not encounter any difficulties.

Because the kobold people have cheap and large bowls of steelmaking technology - fried steel, steel filling, crucible steel, they have all played, so the heavy artillery uses the structure of inner steel and outer iron, which can be called a lack of design experience, so they use krypton materials to make up for it.

In the end, the product was a large man with a caliber of 130 mm, a gun body two meters long, a weight of 800 kilograms, and a projectile weighing about nine kilograms.

Of course, by the time the new product passed the test and could be mass-produced, it would have missed the battle of the volcano to clear the 'helmet dog', and could only be used to arm the fortress.

The distance between the dungeon and the volcano sub-base is only 400 kilometers, and for Liu Jingtian, who can fly, it is only a day's distance.

"Helmet dogs like magic, right? That dimensional cave is also considered magic equipment, right? Such powerful magic equipment can be used as bait...... The old man is so witty!"

The dog head had been transporting wood and soil with this magical equipment some time ago, and someone had forgotten that he had such a priceless treasure on hand.

This time, only two ballistas came out of the work, but with the iron ore in the account, Liu Jingtian also arrogantly took out more than 20 six-pounder guns from the inventory and transported them to the front line.

After a few days, more than 1,000 kobolds from the volcano sub-base once again dragged a cart and a small cart to climb the mountain.

This poor volcano has been tossed by the dog's head for more than a month, and the magical creatures that inhabit the volcano are almost completely extinct, and even the seashells on the beach have been swept away. Along the way, only birds and rodents occasionally show their heads, and there is no more vibrant natural scenery than before.

The wheels rolled, and the kobolds who had slain again joined forces all the way, picked the widest cave, and marched into the interior of the volcano.

On Earth, below five meters underground, the temperature is close to constant. And every 100 meters down, the temperature will increase by 3 degrees Celsius, but the temperature underground of this nameless volcano in the other world can be much higher, and everyone has dropped less than 100 meters, and the temperature has risen to nearly 40 degrees, which is like an oven.

"How far is this, little ones!"

Along the way, he picked up a large number of abandoned baggage materials - that is, the ore and equipment that were lost when he was driven out of the volcano by the helmet dog, among which naturally there were six-pounder cannons and 'three cannons' and the like, but they were all bombarded into slag by the magic bullets of the 'helmet dog', and they could only be taken back to the furnace.

The kobold continued to grit his teeth and insisted on descending for dozens of meters, and then he couldn't climb at all - a strong hot wind blew high from the deep hole, and from time to time cold air poured in from a crack, it was really a sea of ice and fire, it was like a sauna.

However, the sacrifice was worth it, and in the distance, the terrible roar of the helmet dogs could already be heard, and it seemed that it was not far from their habitat.

However, the helmet dogs who had suffered a big loss seemed to have learned to be well-behaved, and they did not show up in the face of the approaching army of kobolds.