Castle of Black Iron

Lin Xiuxian smirked as he said, "It's difficult to get this thing. A knight found a few of it from Earth-element Realm a few days ago, after coming back, he deposited it in my friend's store for sale. Take a look at it, whether it's enough?"

Lin Xiuxian said as he passed the lead barrel to Zhang Tie.

After taking that lead barrel, Zhang Tie opened it. Closely after that, a punch-sized golden crystal escaped out of it like a balloon as it flew all the way towards the ceiling. Zhang Tie instantly caught that crystal by hand. After that, he closed the lead barrel.

"Watch out, I also don't know what to do if you let it go..." Lin Xiuxian hurriedly reminded Zhang Tie.

Zhang Tie nodded as he pinched that punch-sized crystal and watched it carefully.

The punch-sized crystal was like a combination of gold and crystal. It possessed the metallic luster and was semi-transparent. What was more marvelous was that as long as you opened the lead barrel, this thing would escape away. Even though Zhang Tie was holding it, he could still feel it struggling to escape away from his hand.

This was also the most expensive and mysterious metal in the world, the raw material of the core components of airboats——air floating gold.

It was Zhang Tie's first time to see the look of the raw ore of air floating gold.

"How many are there in the lead barrel?"

"7 more of the same size!"

"Okay, thanks..." Zhang Tie said as he opened the lead barrel and foisted that air floating gold into it. Closely after that, he put the lead barrel into his space-teleportation finger ring. What was strange was that the air floating gold immediately became calm soon after it was put into the lead barrel.

After that, Zhang Tie took out 14 earth element crystals from his portable space-teleportation finger ring and pushed them to the front of Lin Xiuxian.

Lin Xiuxian and Zhu Daqian watched how Zhang Tie took earth crystals out of his portable space-teleportation finger ring and put the lead barrel into his portable space-teleportation finger ring like performing magic with an amazed look.

Even knights treasured space-teleportation equipment, not to mention these runed instrument masters. The two people had been shocked when Zhang Tie showed this space-teleportation finger ring to them at the beginning.

"F*ck, when this father makes a fortune and promotes to a craftsman master, I will also fetch a portable space-teleportation equipment..." Lin Xiuxian said as he hurriedly put those earth crystals into his portable storage bag one after another. Compared to space-teleportation finger ring, these earth element crystals were also very eye-catching.

"Come on, don't dream anymore. We'd better stock enough earth element crystals and buy some secret item pearls to try our luck in Taiyi City!" Zhu Daqian said after throwing a glance at Zhang Tie's finger ring for a couple of times greedily.

"Your finger ring is too attractive. It's safe in Heavenly Craftsmanship City; however, you'd better take care of yourself outside the city. Even knights would envy you at the sight of it. You're just a LV 10 strong fighter, a knight could kill you and make you disappear without blinking his eyes. If people were possessed by devils, they would be as cruel and cold as demons. Your space-teleportation equipment could easily make people be possessed by devils!" Lin Xiuxian reminded Zhang Tie after putting away his earth element crystals.

"Thanks for your warning, Brother Lin, I see. I also know a bit of disguising skill, I will protect myself outside the city!" Zhang Tie said with a faint smile, "Brother Lin, do you have other methods to get air floating gold? I don't care about the price!"

"Air floating gold is a product in Earth-element Realm. The largest mine of air floating gold is under the control of imperial households of Taixia Country. Nobody else could acquire a large amount of air floating gold. Even this bit of air floating gold is got by a knight in a mine of the Earth-element Realm by fortune. Additionally, air floating gold was useless to commoners as the manufacturing method of airboat using air floating gold is grasped by the imperial households of Taixia country!" Lin Xiuxian threw a serious glance at Zhang Tie as he continued, "As for our rune instrument masters, this rune of air floating gold has poor compatibility. It couldn't combine with other metals. Even though you could make a set of equipment using air floating gold, you couldn't use it at all as it was as unstable as flying a kite. You couldn't even determine the direction. Previously, a rune instrument master in this city made a pair of wings using air floating gold, which looked pretty dignified. However, as he failed to control his direction in the air, he almost killed himself. What do you want it for..."

"I'm designing a set of the wholly new steam centrifugal ballista. As the bearing of the principal axis of steam centrifugal ballista that we use now is facing issues such as overheat and poor endurability when running at a high speed. I prepare to collect some air floating gold and make a set of suspension bearing which is featured by zero wear and high endurability..." Zhang Tie said as he started to draw it on the table by hand.

As this bar was especially for rune instrument masters, it was common for rune instrument masters to discuss weapons, equipment and their design drawings. Therefore, the surface of each table here was magnetic rune plotting platform. Anyone could draw something on it for the sake of discussion whenever they got the inspiration.

Zhang Tie just drew the drawing of the illusory steam centrifugal ballista on the table.

As a rune instrument master, it was his basic skill to draw. Zhang Tie's drawing was as same as the blueprints drawn by other designers by rulers and compasses. His lines were so straight and his rounds were perfect. It took Zhang Tie less than 1 minute to finish drawing the sketch of the steam centrifugal ballista together with the approximate parameters.

Lin Xiuxian and Zhu Daqian watched the sketch seriously as they winked and considered about it. After a while, Zhu Daqian stroked his jaw as he asked Zhang Tie, "Your design is a bit interesting. The main turntable of your steam centrifugal ballista is akin to the traditional energy storage flywheel. Such a design requires the flywheel to run in a vacuum so as to reduce the energy loss. Additionally, with the non-contact suspension main bearing, the flywheel could reach its maximal speed; as a result, the ammo would gain a much greater initial velocity. However, it requires many times higher cost; especially that the suspension main bearing should be made of air floating gold. Given the input and the output, it's not economical. You could make over 10 ordinary steam centrifugal ballistas and could gain a few times greater effect when you spend time making one of it. Do you want to attend the annual competition on the range of steam centrifugal ballistas held by Rune Instrument Masters Union..." Zhu Daqian asked as he threw a couple of times more glance at Zhang Tie. After that, he shook his head too as he said, "That's impossible. That match is specially set for rune instrument masters below rune craftsmen. Old Tie, you don't need to join in the fun..."

"No..." Lin Xiuxian's eyes shone at once as he said, "Old Tie, there's something else that you've not presented to us, here..." Lin Xiuxian said as he pointed at the sketch on the table, "Old Tie, something should be here..."

Zhang Tie let out a sigh inside, 'What an experienced man! After staying in Heavenly Craftsmanship City for a few decades, this guy really has an unusual insight. He found an interface for a reserved function module from the sketch.'

Now that Lin Xiuxian had already noticed it, Zhang Tie didn't need to hide it anymore. Therefore, he added something with an ordinary symbol that was widely accepted by rune instrument masters on the place where Lin Xiuxian pointed at.

"High-speed vacuum flywheel's centrifugal disk made of air floating gold plus an explosive high-pressure steam propulsion valve. Even though it requires a high cost, it's enough to kill a battle spirit. However, it seems to be a bit wasteful by killing battle spirits using this device..." Lin Xiuxian suddenly watched Zhang Tie with widely opened eyes as he said, "Old Tie, do you also want to make steam centrifugal ballistas that could kill knights?"

Zhang Tie kneaded his face as he answered, "What do you mean by 'also'?"

"Because I've seen the similar design decades of years ago. It was designed by my master; however, he failed in the end!" Lin Xiuxian let out a sigh as he started to improve the sketch, "My master was already a major craftsman when I was young. He was also ambitious about designing equipment or weapon to kill knights. Finally, he chose steam centrifugal ballista as a breakthrough. My master also chose the steam centrifugal ballista with flywheel structure. He thought that the highest speed of revolution of flywheel could reach 200,000 rpm; if a flywheel whose diameter was hundreds of meters, the linear velocity of the edge of the flywheel might reach a terrifying level when its speed of revolution could reach 200,000 rpm. Anything being tossed out at such a terrifying speed would carry great kinetic energy which would kill knights. However..."

"However, did your master find that the greatest linear velocity of the edge of any flywheel could never reach the speed of sound? The theoretical speed of 200,000 rpm of a flywheel is just limited to a small-diameter of the flywheel in a vacuum. As long as the size of the flywheel was magnified, it would meet its physical upper limit!" Zhang Tie replied with a bitter smile.

"Right, therefore, my master thought about giving the ammo an impetus the moment it left the turntable, namely, adding an explosive high-pressure steam propulsion valve at the exit. Even so, my master could at most make the initial speed of the ammo 1,700 m/s after 2 decades' effort, which was only equal to 5 times that of the speed of sound. With such a speed, he could kill battle spirit by steam centrifugal ballista; however, he still couldn't kill knights using it..."

"Then?"

Lin Xiuxian pursed his lips with red eyes, "That old thing didn't admit defeat; he abandoned the design of explosive high-pressure steam propulsion valve and would like to increase initial speed using pure alchemist's bomb. After a few experiments, he was exploded to death due to an accident, leaving me alone in Heavenly Craftsmanship City!" Lin Xiuxian watched Zhang Tie as he said seriously, "Old Tie, I know you don't lack money; however, many top rune instrument masters wanted to break through it and carve themselves a place in history and reach their heyday; however, none of them succeeded..."

Zhang Tie knew that Lin Xiuxian was telling the truth, because what he said rightly verified what Zhang Tie got in his lab and Castle of Black Iron over the past 2 months. The maximal linear speed of the edge of the flywheel of steam centrifugal ballista could only approach 340 m/s infinitely. In terms of explosive high-pressure steam propulsion valve, the upper initial speed limit of the ammo could not reach 2,000 m/s.

"I still want to have a try; there might be some other method!"

"There're two methods. First, to have the linear speed of the flywheel break the speed of sound; second, to add a greater impetus to the steam centrifugal ammo; however, we've already seen the upper limit of that. Alchemist bomb doesn't work at all. Because of its overreaction, it would kill yourself ahead of the enemy..."

"Steam and alchemist bombs are not the mere methods!"

"You're right. Before my master passed away, he suddenly became greatly discerning and apprehending. He said someone might be able to increase the initial speed of ammo or break through the maximal linear speed of the edge of the flywheel in terms of runes array. However, only god-level craftsmen could grasp the knowledge of runes array. Less than 10 god-level craftsmen could be found in Taixia Country. Importantly, none of the runes adopted by modern runes instrument masters could increase speed for lifeless objects. The Rune Instrument Masters Union spent a lot of money and time in seeking for such a far-ancient rune from the Earth-element Realm annually. However, they always failed. I even doubt that there was not even such a rune even in far-ancient times. Old Tie, the road that you chose would be very very difficult..."

"I know it would be very very difficult; however, at least I have two methods to go. If not try them, I would feel regretful for the rest of my life. I will do my best and leave the rest to Heaven!" Zhang Tie also let out a sigh.

Over the past 2 months, after so many attempts and failures, Zhang Tie maintained his belief. He was more aware of the road facing him. If it was an easy way to go, it might have long been occupied by others numerous times.

"If so, wish you good luck. I will have to leave Heavenly Craftsmanship City in a couple of days. Hongsheng Palace, Yunzhou City is going to build a Class A city, as I acquaint with an elder of Meng Clan, he invited me to preside over the establishment of the city-defense system of the city with the compensation of 1 billion gold coins. Just go to make some pocket money. Therefore, I want to bid a farewell to you two here..."

Zhu Daqian replied with a bitter smile, "You also have a part-time job? I might go to Military City in a couple of days!"

"What's up?"

"As I invented a mini nitrogen separator previously, I know something about separating nitrogen from the air. I didn't think it was useful; I've not imagined that an official of the Weiji General's Mansion found me yesterday and invited me to attend the design of a weapon program in a military arsenal of Huanzhou Province..."

'I've not imagined that Zhu Daqian's schedule is related to me.' Zhang Tie sighed with feelings that it was such a small world. Of course, the one who came here for Zhu Daqian was not arranged by Zhang Tie himself. Zhang Tie estimated that it was a subordinate of Lu Yanyu. In this case, Zhang Tie didn't know what to say.

"What weapon program?"

"A Fiery-Oil driven flaming tank. I'm responsible for the liquefying nitrogen device in the tank!"

"Flaming tank?" Lin Xiuxian was stunned evidently; however, Zhang Tie remained calm because it was within his expectation. When he took out those Fiery-Oil weapons from Fiery-Dragon Bounty Territory, he had guessed that Taixia Country would make more destructive weapons based on their overall strength. Zhang Tie's invention was just a beginning.

"Of course, look at the provinces in the theater of operations. They're all busy building Fiery-Oil bases. All the farmlands have been covered with Qianji Hermit's fermentors of earth pulp and earthworms rearing pools. This scene is even more boisterous than when in peacetime. Qianji Hermit really has unpredictable abilities. Previously, the 4 provinces were filled with negative emotions; only after he served as Weiji General for a few months, all the disappointed emotions have been dispersed while all the commoners, major clans, officials became active and many factories in this city started to study Fiery-Oil weapons. No wonder he was appointed as Weiji General by the commander-in-chief!" Zhu Daqian said with full of admiration.

"Ahem, ahem, Qianji Hermit might only be a bit fortunate. It's said that he's still young and knows nothing at all!" Zhang Tie pretended to cough twice before saying.

"Hahaha, Old Tie, we all know that you're ambitious; however, Qianji Hermit is indeed an affectionate and righteous man. His military exploits and meritorious deeds could never be matched by us. It's said that he's the founder of Iron-Dragon Sect in Youzhou Province. Last year, Old Zhu and I were talking about seeking refuge in Iron-Dragon Sect after we were bored of this city. Based on our abilities, we might not be refused..." Lin Xiuxian said while bursting out into laughter.

"Based on two elder brothers' talents, if you go to Iron-Dragon Sect, Qianji Hermit would definitely open a palace for each of you!" Zhang Tie replied with a smile.

"Hahaha, thanks for your auspicious words. Oh, how long will you stay in Heavenly Craftsmanship City? If you plan to stay here for a longer time, I will introduce you to some friends..."

"I would leave soon too. After coming here for over 2 months, I've made a great achievement. I've realized that something could only be done step by step. As it's growing more and more chaotic, if that thing couldn't be invented for the time being, I'd like to cultivate for a period seriously first. Hopefully, I would promote to a higher level as soon as possible. It's not bad whatsoever!"

After coming to this city for 2 months, Zhang Tie's greatest achievement was that he understood what difficulties and obstacles he would overcome in order to make his dream come true. It couldn't be reached in one day. It couldn't even be done by himself based on his current rune instrument manufacturing level. After realizing this point, Zhang Tie had determined to leave as it would be meaningless for him to further stay here.

He didn't need to care about the rear end because he had made arrangements properly in all aspects. As long as they proceeded it orderly, there would not be any big trouble. Therefore, Zhang Tie would like to deepen into the theater of operations alone only for promoting to a shadow knight first. The so-called Weiji General was unrealistic in Zhang Tie's eyes because the title could be conferred and canceled whenever the commander-in-chief wanted. The vanity meant nothing for Zhang Tie. Additionally, Meng Shidao was observing him in Xuanyuan Hill maliciously; Zhang Tie didn't want to be involved in the officialdom of Taixia Country too much as it was not necessarily a good thing for him.

As for a knight, battle strength and rank were their largest dependence. After deepening into the theater of operations, he could at least kill some demon nights or give demons and Heavens Reaching Church a hard time so as to make the rear end less stressed. Over the past 2 months, although Taixia Country didn't face that urgent situation anymore; it was still not facing an optimistic prospect. As a knight, Zhang Tie really couldn't waste time at this critical moment...