The principle of hot air balloon is very simple, there are only two difficulties in making, one is the combustion device, and the other is the airbag.

The first point is that in the absence of a pressure vessel to provide gaseous fuel, firewood or charcoal alone to heat the air, the efficiency is not to mention, and the fuel limit can not fly far.This is also the long history of the discovery of the principle of hot air balloons, but the first to be put into use in the actual battle is the reason why hydrogen balls.So Roland simply gave up the incendiary device and let Anna ignite the heat.

The difficulty of airbags is confined, but for Roland, who has learned from the experience of his predecessors, this problem is easy to solve and use mezzanine fabrics.The outermost layer of the airbag is a wear-resistant canvas, with a kraft film in the middle, and a lightweight gauze in the inner layer, so that it can be stitched to prevent leakage, while not afraid of the peek of birds.

Roland propped open the bottom of the airbag, allowing Anna to squive a black fire close to the temperature and ordinary flame, and the airbag slowly bulging up, looking like a folded winter melon.Considering that the hot air balloon needs to carry two people to lift off, the width of the airbag is five meters in diameter, and the intestinal membrane of the twelve cows is used, and the sewing work is close to a week.If it is not the lord who governs a place, it is not necessarily able to make such a big toy.

“Does it fly with the buoyancy provided by heat?”Anna asked, "I remember that the hot air always rises."

"Yes, hot air rises and cold air sinks is a common natural phenomenon.To explain the particle theory, it is that the hot air small ball movement is intensified, the ability to spread around, and the density will become smaller after the volume expansion.For the unaltered air, it is as light as it becomes lighter and therefore rises.”

After Roland finished the principle, he found that in addition to Anna showing such an expression, the other three people were dazed, making him secretly lament the importance of talent.

When the airbag completely expanded and floated upwards, the traction rope was slowly straightened, Roland first turned into the hanging basket, and then took over the climbing Anna.

"I'm still a little worried," said Nightingeon uneasily, "or you'll let me go up and try it first."

"Believe me, nothing will happen," Roland smiled easily, "and even if an accident happens, there's lightning."

"I'll catch them, don't worry."The lightning patted his chest.

“And me and I choking!”Maisie learned to pat the chest with the appearance of lightning.

With a wave of shaking, the hot air balloon led the hanging basket away from the ground and gradually climbed up.Not long after, the two crossed the top of the castle, and the whole picture of the town appeared in front of them.

For Roland, such a scene is not strange, after all, he is also a person who has seen the skyscraper, but in Anna's eyes, it is a completely different experience from the previous perspective.She lay on the edge of the hanging basket probe and looked out, and one hand firmly grasped Roland's arm, which seemed excited and nervous.

This is the first time Roland saw her show such a look, probably the feet have never been far from the ground, the first time to fly to the sky, will produce a slight feeling of fear.

Soon, the hemp rope used to tie the hot air balloon under the hanging basket was pulled to the limit, and the rise stopped.The rope is about 50 meters long, which is the height of the next fifteen or six floors.Roland let Anna reduce her firepower, and the hot air balloon eventually hovered in the air.

At the beginning, the lightning was still on the edge of the hanging basket, and when he saw the basket stabilized, he also rested assured that he was playing a chase game around the hot air balloon with Maisie.

From here, you can clearly see the roof of the castle, the small towns under construction everywhere, the red water river flowing from west to the east, and the verdant farmland along the river.

“How do you feel?”

It wasn’t until Anna pulled back her head that Roland asked with a smile.

"Thank you for the gift," she said excitedly, "that I can fly so high."

"It can be higher," Roland sat down on the side wall of the rattan basket, "if the line below is longer, flying ten times the distance is no problem, but the more the upper airflow is more complex, the safety is difficult to guarantee."And this is just a primary flying machine, and when a piston machine is built, ordinary people can fly faster than birds, higher than birds, and then...” He looked up at the blue sky, “People can even fly out of this world and go to boundless space.”

Anna held her breath, her eyes gleaming, something calling out.

"Fly out of the world, I can't guarantee," Roland was teasing at her look, "but make a piston machine so that ordinary people can fly like birds, and they should still be able to do it in their lifetime."In fact, there is Anna, the processing capacity has no bottleneck, the current short board exists in the material properties.Poor quality raw iron can be combined to make steam engine, cooked iron can make guns, with black fire smelting steel wheel gun is not a big problem, but the internal combustion engine, I am afraid that you need high-quality cast iron, cast steel or aluminum."The border town can be as it is, and all this is to your credit, Miss Anna."

After hearing this, Anna stopped.After a while, she sat down and whispered, “My mother died in a fire, but instead of being buried in smoke and fire, I became a witch.”For a long time, I thought that my awakening had led to the fire and that I hated myself as a witch.When I was in prison, thinking that this might lead to liberation, you saved me from prison and taught me how to use power... I did not think that the flame could be of so much use than to bring burning and suffering.”Anna paused, "I should be satisfied with you, but now I find that my thoughts have changed, and sometimes I feel depressed and want more."

She climbed Roland’s shoulder and said, “Even then, do you want to hire me?”

Her lake blue eyes were sparkling, breathing blew on her face, some itchy feeling.In the thin clothes, he could feel each other's soft body and thumping heartbeat.Nevertheless, she did not avoid the look of eyes when there was no nightingle, she was always full of enthusiasm and initiative.

“There’s out there...”

Roland had not finished, and Anna had closed his lips.

After separating, he took a soft breath, “I want to hire you, all the time.”“Miss Anna.”

“Hmm.”

This time, he bowed his head and held her close together.

...

"Well, wait," said Maisie, after chasing the lightning for a moment, and suddenly a hasty stop in the air, looking out at the empty hanging basket, "they're gone!"

“Ah?”The lightning glanced at him, "They just sat down."

“Can’t you see the outside view?”

"The scenery can be seen at any time, but there are not many opportunities like this."

“The opportunity?”Maisie shook her wings and fell on the shoulder of the lightning, "I don't know how, do you want to go and see them?"

"That can't be done," said the lightning, holding the pigeon, "this is a sacred ceremony, and it cannot be interrupted."

“Goo?”

"Anyway, you'll see later, at such times, as long as it's not seen, that's what my father's greatest explorer told me."The lightning threw out Maisie, forked the waist, "Now run, let's change me to follow you!"(Not completed.If you like this work, you are welcome to start the campaign, and your support is my biggest motivation.Mobile phone users please read.)