The human-powered tricycle is undoubtedly a sophisticated machine for people in this era. And the best at tinkering with precision machines in this era are those watchmakers.

Leonardo da Vinci learned a few hands from these watchmakers in the first place, and in the original history, he tinkered with a robot lion, clockwork driven. And the technical content of the human-powered tricycle will definitely not be higher than that robot lion.

However, Leonardo da Vinci now has a heavier task, taking two groups of students to develop diesel engines and steam engines, and teaching a group of chemical engineering college students.

So, even though Leonardo da Vinci was the most suitable, Marin still didn't ask him to develop a human-powered tricycle. After all, people are already too busy to keep their feet on the ground. If you go to him to work on a rickshaw again, it will definitely tire people to death......

Moreover, human-powered tricycles and bicycles were familiar to Marin in his previous life. After all, you have it all at home. Before the rise of electric vehicles, Marin's family basically used bicycles to travel. And when you go out to transport something, except for the use of walk-behind tractors at the large scale, a small number of items are basically carried out by human-powered tricycles.

Because I have been using bicycles and tricycles for a long time, there have been many problems in the middle, and I have repaired them many times. So, with his eyes closed, Marlin could remember the structure of a bicycle and a rickshaw.

Therefore, he doesn't need a big guy like Leonardo da Vinci to come out, as long as an ordinary clockmaker with good craftsmanship can make a human-powered tricycle under his guidance. As for the bicycle, which he was more familiar with, because it didn't mean much to have a rickshaw, Marin was going to put it first.

Moreover, when a rickshaw is made, the bicycle is just a simple change, and there is no difficulty.

The only problem is probably the supply of engine oil required by the chain and the supply of rubber tires. After all, when the human-powered tricycle becomes a popular means of transportation, the consumption of engine oil and rubber tires required for the chain will definitely be relatively large.

Although he hasn't done it yet, Marin has never worried about whether the rubber tires can be made. He is only worried about the consumption of rubber tires, after all, in later generations, bicycle tire changes are a common thing, and the consumption of rubber tires is very large.

Today, however, the production of natural rubber is limited. Although the new natural rubber is planted, it will take six or seven years before it can be tapped...... Therefore, Marin suddenly felt that the cultivation of natural rubber needed to be expanded! Otherwise, once the human-powered tricycle is made, the consumption will be amazing......

In addition, the production of chain engine oil should also be increased. Therefore, the pace of oil development should also be accelerated. After all, engine oil is also refined from the residues of high boiling points after gasoline, diesel, and kerosene are refined from petroleum.

In addition, the research and development of wear-resistant tire technology also needs to be put on the agenda. Marin remembers that the tires of later generations of automobile tires were made of carbon black, which could increase the wear resistance of tires by ten times. Originally, the white rubber tires that were not mixed with carbon black had a lifespan of only 8,000 kilometers. When incorporated with carbon black, the service life is increased tenfold.

Therefore, Marin also needs to order his subordinates to study how to mix carbon black powder into the white tire tires. Also, you need to control the amount you add. This requires many attempts. But after knowing the principle, at least you can avoid a lot of detours.

In addition, Marlin will also take one step and directly adopt the radial tires that were popular in later generations. In this way, there are too many detours to take. As long as the research of radial tires with carbon black is successful, and the production of natural rubber is greatly increased, the wheels of vehicles in Beihai will be the world of rubber tires in the future.

But first, the source of rubber should be sufficient......

Although Marin knew about synthetic rubber, he didn't know chemistry and didn't know how to synthesize rubber. Therefore, he can only choose to grow more natural rubber.

In later generations, the largest natural rubber production areas were in Southeast Asia, such as Malaysia and Indonesia. But Marin knows that the reason why natural rubber is produced in Southeast Asia and not in the Americas is because in the nineteenth century, when the use of natural rubber was discovered, most of the countries in the Americas became independent, and only Southeast Asia and other places were still European colonies. Therefore, Europeans can only vigorously develop rubber cultivation in places such as Malaysia and Indonesia in Southeast Asia. In the Americas, however, the promotion is less so.

Therefore, it is not that rubber cannot be grown in the Caribbean, but that when rubber is promoted and planted, many countries in the Caribbean have become independent. Or, because of the small size of the island and the lack of labor, rubber cultivation has not been promoted.

After all, growing natural rubber and tapping rubber are labor-intensive industries that require a lot of labor. At that time, there were many Malays in Southeast Asia, and there were hard-working Chinese immigrants available, so a large-scale rubber plantation industry was developed.

Today, Marin has no industrious Chinese laborers available. But it is still possible to plunder tens of thousands of laborers from the million-strong island of Haiti to grow natural rubber. It seems that Haiti in later generations also produced natural rubber.

But Marin was very jealous of syphilis on the island of Haiti, so he did not plan to engage in rubber cultivation on the island of Haiti, but planned to take all the Taítans who did not have syphilis away from the island. Then, the remaining syphilis patients on the island were left to fend for themselves. When all these syphilis patients are dead, Marin will have to wait a few years before he can bring people back to develop the island of Haiti.

For this reason, Marin has issued an isolation order to isolate all people infected with syphilis, whether Europeans or natives. The islands, which have a large number of syphilis patients, will also become temporarily isolated.

In fact, in addition to the prevalence of syphilis among the Taíno people on the island of Haiti, there are also many Taíno tribes in the eastern part of the neighboring island of Cuba who have syphilis patients.

Therefore, while ordering the development of the Guantanamo area, Marin also planned to send troops to clean up the Taíno in the eastern part of the island of Cuba in the future. Once syphilis carriers are found, they are isolated and left to fend for themselves. The ultimate goal is to eradicate all sources of syphilis.

Syphilis is too contagious, and although Marin knew that penicillin could treat syphilis, he believed that it was better to eliminate the source of syphilis, which would be more worry-free and trouble-free.

The source of syphilis is also on the island of Haiti and several neighboring islands. Marin planned to take advantage of the opportunity to conquer the island of Haiti and send four or five thousand soldiers and horses, plus two thousand Mao Gonggong, to inspect the islands in the Caribbean in turn and isolate all syphilis patients. And use lime powder and other things to completely kill the virus, in order to eliminate the source of this evil disease.

At the same time, during the inventory of syphilis patients, those Indians who did not have syphilis were also taken away to help Marin grow natural rubber.

In this way, it can be regarded as killing two birds with one stone. It not only eliminated the source of syphilis, but also brought a large number of laborers to help Marin grow natural rubber. When rubber tires become popular in the future, there will be no supply difficulties.

Of course, in order to prevent the aborigines from dying out of a disease like smallpox, Marin would first let them all be inoculated with cowpox, and then they would not be afraid of smallpox.

In addition, Marin intends to implement a strict quarantine regime and conduct strict health checks on Europeans traveling to the Americas, so as to prevent Europeans with serious diseases from bringing infectious diseases to the Americas and triggering the extinction of the natives. In this way, he will not be short of labor.

In order to prevent the natives from having a sense of ownership in their homeland and confronting the colonial authorities, Marin would find ways to take the natives out of their homeland and bring them to other places. In this way, it is not easy for them to do things if they are not familiar with the place. For example, the Taíno people on the island of Haiti, after being brought to Cuba, will become very honest for a long time. And after they get acquainted with the local area, if they want to be dishonest, they don't have a chance. Because, Marin won't give them a chance...... In addition, the Beihai Kingdom does not treat the indigenous people badly, as long as they can make do with it, no one wants to go to the dead......