Marco Polo passed this way, a lad in his teens accompanying his father and uncle on their arduous four-year journey from Venice to the court of Kublai Khan.
So, 1,300 years before him, did Chang Chien, emissary of the powerful emperor Wu-Ti of the Han Dynasty, spying out the ''western regions'' and hoping to obtain the swift horses of Ferghana for his master's cavalry.
So did a host of generals, officials, merchants, priests, plunderers, and adventurers from east and west, seeking conquest, or riches, or religious enlightenment, on what Westerners came to call the Silk Road from China to Persia and on to Byzantium and Rome.
The Silk Road thrived when China was strong, when the emperor's writ ran from the Central China Plain to the steppes of central Asia. It declined when, under the Ming Dynasty (1368-1644), Chinese armies withdrew behind the Great Wall, and the sea route to India and Europe became safer and more reliable than camel caravans across the Gobi Desert.
Today, under the People's Republic, China is strong again. But for the people of the oasis towns of Jiuquan and Jiayuguan, Dunhuang and Turfan, the Silk Road is a memory, useful mainly in attracting tourists from distant Europe and America.
The two-humped Bactrian camel has been retired from service as the ship of the desert, except to carry occasional scientific expeditions. You can pick up a camel in Dunhuang for 300 yuan (less the $200), less than what a good mule or horse might cost. You can use a camel to pull a cart, but he eats too much and is not as versatile as a donkey or a horse in plowing a field or taking goods to market.
Instead of being exotic staging posts on the way to Europe, cities farther along the Silk Road, like Kaxgar or Aksu, are sensitive military garrison towns, closed to most foreigners, alert to what the Soviet Union may be planning on its side of the central Asian frontier.
China no longer looks outward along the old Silk Road, as it did in the spacious days of Tang, when merchants from Persia and holy men from India jostled emissaries from the eastern seas in the broad, straight streets of Changan, present-day Xian.
Instead, it has paved and slightly rerouted the Silk Road, paralleling it with a railroad that ties Sinkiang -- for many years known more romantically in the West as Chinese Turkestan - more closely to what used to be called China proper than any preceding dynasty.
The railroad, an extension of the east-west Longhai line from Sian through Lanzhou to Urumchi, capital of Sinkiang, fulfills Dr. Sun Yat Sen's vision of a unified China securely held together by trunk lines crisscrossing the country east to west and north to south. Lanzhou, the jumping-off point for excursions along the old Silk Road, has become not only a metropolis of 1 million inhabitants, but also a communications hub, with rail lines radiating east to Sian and Shanghai, north to Inner Mongolia and Peking, west to Urumchi, and south to Sining nd Golmud in desolate Qinghai Province. The Sining-Golmud line will eventually extend to Lhasa, capital of Tibet.
One thing the Lanzhou-Urumchi line definitely will not do is link up with the Soviet Turksib railway, although in the early 1950s, the days of euphoric Sino-Soviet brotherhood, such a link was planned. It would have had the modern version of the old Silk Road ending in Moscow.
Nevertheless, as one voyages from oasis to oasis along the modern version of the Silk Road, sometimes by bus or car, sometimes by slow-moving train still pulled by hissing steam engines, one is aware of moving out along the fringes of Chinese civilization, culture, and language into an area of marches where the ethnic Chinese presence is progressively diluted by Tibetan, Mongol, and Turkic minorities until, crossing from Dunhuang, the last ethnic Chinese oasis, into Sinkiang, the Chinese themselves, or the Han, as Peking calls ethnic Chinese, have become a minority.
Of Sinkiang's 12 million people, 7 million are non-Han, according to Wang Wenheng, chief spokesman on minority affairs for the Chinese Communist Party in Sinkiang. The largest ethnic group, the Uighurs, number slightly more than the next largest group, the Han - both are about 5 million strong. The rest are a veritable crazy-quilt pattern of peoples, from Kazakhs and Hui (Chinese Muslims)to Kirghiz, Mongol, Tajik, Sibo, Tatar, Uzbek, Manchu, and even 1,000 Russians who hold Chinese passports.
Already, in Gansu Province (of which Lanzhou is the capital), taking the bus from Jiayuguan (where the Great Wall ended in Ming days) past the Yumen oil fields, the ruined Fortress of Qiaowan, the oasis town of Anxi, to Dunhuang, verdant in the desert now as it was in Marco Polo's day and for at least 1,000 years before that, one is aware of the majestic line of the Qilian Mountains, perennially snowcapped, keeping one company from oasis to oasis.
Behind the Qilian Mountains are the Tibetans, who repeatedly marauded the oases until a wise Tang emperor sent his daughter, the Princess Wenching, to marry the Tibetan king of those days. Northward stretches the Gobi, across which Marco Polo traveled from Dunhuang to Karakhoto (Heicheng, the black castle) and then to Shangdu (present-day Chengde) north of Peking for his first audience with Kublai Khan. The Gobi is Mongol, even today. It is only the narrow strip of the Gansu corridor, stretching 600 miles from Lanzhou to Dunhuang, that remains ethnically Chinese, and even here one can come across Tibetan peasants and Mongol or Kazakh herdsmen.
The flat wheatfields of the North China Plain, the square-hulled junks and the green rice paddies of the Yangtze Valley seem far away. Here all is sand and stone, fine dust and baked mud. The trucks that roar past on the modern Silk Road may be carrying oil-drilling equipment for the Cai dam in Qinghai or Karamai in Sinkiang. Who knows? Under the tarpaulin may be top-secret nuclear or rocket materials for the missile testing station at Lop Nor near the ancient ruins of Loulan. Marco Polo might be bewildered by the gas-guzzling behemoths that have replaced his two-humped camels. But he would be reassured by the donkeys and mules still plodding along in the trail of the dust raised by the trucks. He would soon realize that even heavy-duty trucks must halt for their own security when sudden swirling sandstorms turn the sky black and rain basalt pebbles against their windshields.
He would know that as in his day, so in ours, the most welcome sight in these desolate parts is the green of trees, the sparkle of water. Man and his inventions have changed along the old Silk Road, but nature remains the same.