"However, even if it's black lazuli, I can still break it!"

"Look at the move, fire slash!" Ma Xuyun burst out, the treasure knife in his hand turned into an orange-red light, and then, a loud explosion came. Pen ~ fun ~ pavilion www.biquge.info

"Boom........!" There was a flurry of swaying in the underground water transportation channel, which showed the power of Ma Xuyun's move just now.

"Plop plop ........plop!" Countless gravel fell into the water with a loud sound.

".......!" the water in the underground water passage poured on the fiery red walls, making a loud sound, and then....

"Click......!"

"It was hit by these people by mistake, and the thermal expansion and cold contraction made them speed up the speed of destroying the black gold stone wall, and it was not bad to transport!" Lin Ze on the ground smiled.

Originally, it would take about half an hour for Lu Ming and the others to get through the stone wall built by the Black Gold Stone, but now it seems that they can get through it in about ten minutes at most.

The reason is very simple, it is because of thermal expansion and contraction.

Using the principle of thermal expansion and cold contraction to destroy stones, such a thing was very common in ancient China.

In ancient times, when there were no explosives, this method was used to mine ores and stones, and to destroy hard stones when building roads.

First of all, a lot of firewood is placed on top of the stone that needs to be mined, or the stone that needs to be destroyed, and then it is lit, and the stone is directly heated and red, and then a basin of cold water is poured directly on the reddened stone.

"........ "As these sounds sound, you will magically find that this hard stone is starting to crumble.......

This method is best for breaking stones, but if you want to mine stone, there is another way.

This method takes a little longer, and the principle is the principle of expansion.

Drill a few holes in the stone with an iron drill, then drive a piece of wood about the size of the hole into the hole, and then pour water on the log.

When the wood is soaked in water, it immediately begins to swell and the stone cracks.......

"Haha...... , God help me, with this water, we can get out faster, hahaha......." Seeing a large amount of black gold stone falling rapidly under the watering of the water, Lu Ming and Ma Xuyun laughed.

"Captain Ma, come on, we have to open the hole as soon as possible, the enemy may start to act now!" Happy to happy, Lu Ming still understood it very well in his heart, so he urged Ma Xuyun to speed up.

"Okay, Commander Lu, I understand!" After speaking, Ma Xuyun transported the true qi of his whole body together, turned into flames, and slashed towards the black gold stone wall in front of him.

At the same time, Lu Ming on the side also transported the true qi of his whole body, which also turned into orange-red flames, burning the black lazuli wall, and when the time was right, he used the true qi to set off a large amount of water to wash the wall, making the black lazuli naturally burst.

Some people may wonder why Ma Xuyun and Lu Ming's true qi are both fire attributes?

In fact, it's not just Lu Ming and Ma Xuyun's true qi that is fire attributed, in the Black Wind Thief, no, in the sea of thousands of miles of sand, the vast majority of the true qi attributes of the martial artists here are fire attributed.

The temperature in the sea of sand is extremely high, and the temperature is 256 degrees Celsius in the winter when the temperature is the lowest, and the temperature is about 378 degrees Celsius in normal times, and 60 degrees Celsius is not a problem when the temperature is high in summer.

Such a high temperature has led to the aura here, and the aura above the eighth layer is all fire attribute aura, so most of the martial artists who cultivate here have fire attribute true qi.

Changing to a water-attribute martial artist to cultivate here, isn't this asking for hardship?!

Cultivating water-attribute martial arts in a place like Wanli Shahai that is full of fire aura, this martial artist is either a fool or has his head hit.

"Boom, ........boom, boom!" A loud explosion came from inside the underground water channel, and many people on the ground heard these unusual movements underground.

Soon, these abnormal movements were reported to Lin Ze's City Lord's Mansion.

"My lord, there is a report from below, there seems to be an unusual movement underground, many people have heard it, there is an explosion below, I went to see it myself, and found that there seems to be someone fighting underground. Tie Ying came to the City Lord's Mansion with a puzzled look and said to Lin Ze.

"Hehe, don't make a fuss, I have already discovered the enemy underground, and now there will be a battle below, because I sent people down to eliminate these people, so that everyone should not make a fuss!" Lin Ze replied with a smile.

Tie Ying and these people don't know about the situation underground, and it takes time to understand such a complex underground water transportation channel, plus this time the infiltrators are some powerful martial artists, let Tie Ying and them deal with it, Lin Ze believes that Tie Ying and these people will definitely have huge casualties, and even Tie Ying, the masters that Lin Ze has worked so hard to cultivate, will also have big casualties, so this time to eliminate the invading Lu Ming and others, Lin Ze himself came.

"Your Excellency is wise!" Tie Ying looked at Lin Ze with admiration, he didn't expect that Lin Ze had already made such preparations.

"Tie Ying, wait a minute, you will take someone to the big water point on the left side of the east city wall, and bring me those ground rats underground when the time comes. Lin Ze commanded.

"Yes, my lord!" Tie Ying quickly went down.

..............................................................

At this time, in the camp of the Black Wind Thieves, Xiao Quan didn't look at Liu Yu and his party who knelt on the ground and pleaded guilty, all his attention was now at the East City Gate.

"Now Lu Ming and they should arrive at their destination, that is to say, there will be chaos at the East City Gate soon, and I have to prepare here first. Thinking of this, Xiao Quan directly said to his eldest son Xiao Chengji beside him: "Chengji, you go to the heavy cavalry unit now to prepare for the attack and wait for my order!"

"Father, what do you mean........" Xiao Chengji was confused, he couldn't figure out why Xiao Quan asked him to go to the heavy cavalry unit now.

This attack has already failed, and even if it is necessary to start the next attack, the heavy cavalry will not be allowed to attack.

Let the heavy cavalry attack a large city with a height of forty or fifty meters, this is not an attack, but a send-off.

"Inheritance, Lu Ming and they have already infiltrated Black Sand City!" Speaking of this, Xiao Quan had a smug look on his face.

"Father, this ....... , is this true?" asked Xiao Chengji with a look of disbelief.

He had already found out that Lu Ming and the personal guards were missing, and at that time, he was wondering in his heart whether Lu Ming and these personal guards were sent out by his father to do some special mission.

Unexpectedly, this is indeed the case, they were all sent by their father to infiltrate Black Sand City.

"Of course, didn't you notice that Lu Ming and the guards around Wei's father are gone, they were all sent by Wei's father to infiltrate Black Sand City. Xiao Quan explained with a smile.

"Father, how did you let them enter Black Sand City? Could it be that you have any secret path in your hands?" Xiao Chengji was worthy of being Xiao Quan's most valued eldest son, and quickly thought of the reason.

"That's a good guess, inheritance, father, I do have a secret passage into Black Sand City, hehe........" Speaking of this, Xiao Quan smiled very proudly.

"There really is!" Xiao Quan's affirmative answer relieved Xiao Chengji's nervous heart.

"Father, you have such a secret passage, why didn't you say it before, we don't have to lose so many vanguard troops, and it won't be long before we attack directly through the secret passage?"

This is exactly what Xiao Chengji can't figure out, if there is a secret passage, why does Xiao Quan still let the vanguard army go to death, and directly send the army to enter Black Sand City through the dark passage, isn't it good?

"Alas, this dark passage is not large, and can only accommodate small troops. Xiao Quan explained, and at the same time, he decided in his heart that after recapturing Black Sand City this time, he would directly dig a hidden passage.

If something like this happens again in the future, you can enter the city through this secret passage.

"Oh, I see!" Xiao Chengji said with a sudden expression.

"But, father, can you tell me where this secret passage is?" Xiao Chengji's face was curious.

Not only Xiao Chengji, but even other people, including Liu Yu, who knelt on the ground and pleaded guilty, were also full of curiosity in their hearts.

"Actually, everyone has seen this secret passage, but everyone won't think of it!" Xiao Quan replied with a smile, he was not prepared to keep the matter of the underground water passage secret.

He sent an army of nearly 4,000 to infiltrate the underground water channel, and this matter would be exposed sooner or later, so he was ready to say it without concealing it at all, so as to increase the loyalty of the underground people to him.

After all, Xiao Quan didn't hide such a secret thing from his subordinates, which means that he really treats his subordinates as his own.

Who wouldn't want to work and serve such a person who thinks of himself as his own?!

"Oh, we've actually seen each other before. Xiao Chengji began to recall in his mind, trying to find some special memories.

It's a pity that he searched for all his memories, but he still couldn't find this 'special' memory.

"Hehe, don't think about it anymore, you can't think of it. Xiao Quan said with a smile.

He didn't sell it anymore, and said directly: "Inheritance, you have forgotten the wells scattered around the city wall!"

Xiao Quan directly solved the puzzle.

"Water well?" Xiao Chengji frowned.

The next moment, he suddenly realized: "Father, is it .......?"

"Yes, it's an underground water channel. Xiao Quan replied in the affirmative.