In ancient time, the one, who had been to the desert like Fa Xian in Jin Dynasty and Xuan Zang in Tang Dynasty, all described the desert as a horrible place. Then people had such a deep impression. The book The Diary of Fu Guo written by Fa Xian says there were so many evil spirits and hot wind which would kill people immediately if they met. The desert was so bleak that you wouldn't see a bird in the sky or an animal on the land. It was sand everywhere that you couldn't feature out the way out. You could only follow the bones of dead people and horses to feature the way out. The twelfth chapter of the Western Regions of the Great Tang says it was the quicksand east. The sand was always moving by the wind. The footprint of people and horses would be covered by the sand soon. So it was easy to lose the way.

Is the desert as horrible as what FaXian and XuanZang said? After the Liberation, the workers from the Internal and External Process, the oil Ministry and Chinese Academy of Sciences has gone through the Taklimakan Desert in Xinjiang for many times. However, there is no ghost or something strange which has stopped their way. Why?

Suppose Fa Xian set out only with 7 monks. After a while, someone could bear the pain and left, or someone died on the way. At last, only FaXian was alive. XuanZang went to the desert by himself, too. The so-called Xingzhe Sun (Tripmaster Monkey), Bajie Zhu (a pig), Heshang Sha (a monk) are all created in fairy tale of the Pilgrimage to the West. At that time they didn't have enough water and food carried by the camels, let alone the cars or planes to rescue. Of course, it was hard.

 Does the desert really have the devils? According to the education level of people at that time, it did seem to have devils. However, after we know the nature law, it is easy to explain the strange and fantastic scenery. The strange and fantastic scenery is common to see at noon in summer in the desert. When people were so thirty on their way in the desert, suddenly they saw a big lake with blue water. The lake seemed not far. When they were so happy to go for the lake, there seemed a distance that could exist forever. It is the so-called "within sight but beyond reach". The Arabians have experience in desert. They call this phenomenon as " the Devil's Sea". This phenomenon was discovered by Mundici who was a mathematician and hydraulic engineer at the beginning of 19th century. Mundici went with Napoleon to fight for the colony with UK. At that time, the French soldiers were so surprised to see the " the Devil's Sea" and they went to ask Mendici. After the deep thought, Mendici said the reason was that the sand was so hot in the sun. The air near the ground was much hotter than the air 1 or 2 meters above the ground. Because of the refraction and reflection, people would get into the illusion that the trees grew upside down, the blue sky was reflected on the ground and seemed just like the sea. If the temperature of the air near the ground is 7 or 8 degrees lower than the air above in a short distance, it will be the same just like what we really see near the see. The seldom-seen islands or people under the horizon will be all reflected on the sky in the castle in the air, which can also be called Mirage. We Chinese always use the words "fantastic" to describe this phenomenon, which seems reasonable.

In the desert, not only the ray light can make us feel wired, but also for the sound. XuanZang Tang thought that it was the devils confusing man. Until now, the ones who live in the desert still believe this. People call the sand which can make sound as "singing sand". There is a place called Mingsha mountain ( Singing Sand Mountain) in Zhongwei Town in Ningxia. It is the ShaMen Head now. The Academy of Sciences and the Ministry of Railways set a station to manage the sand. It is the Tengger desert behind the station. The desert here is really close to the Yellow River. The sand is over 100 meters high. It faces the south. There is a spill in the middle which is always with spring water out. The sand here is always admired by man. It is said that people will gather together on the top of the mountain and slide from the slope of the mountain in the Dragon Boat Day. The sand will make a huge sound just like the thunder. Two years ago, I went the the Mingsha Mountain with a few of my colleagues. We did hear the huge sound of the sand when we went down the mountain. The sound seemed like the cars far away. It is said that if the sand is the dry silver sand which contains the quartz, after it is heated by the sun, when the wind blows or people or horses move, the friction of sand can make sound. This is the so-called "Singing Sand". The ancient said "What once seemed bewildering will no longer be so. You will lose if you belive the bewildering." In fact, all the strange phenomenons in the desert can be explained by the science.