It is such an old compass that no one would use it nowadays, but it played an indispensable role in construction of China's first highways on the Qinghai-Tibet Plateau, also known as the "roof of the world", in Southwest China's Tibet Autonomous Region.
About 110,000 builders were sent to Tibet to construct highways linking the region and Qinghai and Sichuan provinces in 1950.
The region at that time was still a blank on the map as no one had ever explored its byways. The only thing to help the builders find direction and plan the highways was the simple, old compass.
The construction team built the highways following the compass's directions in the snow-covered region all around the year, through mountains and across rivers, and against extreme cold and natural disasters.
The compass was the most advanced device the team had for construction at that time. The distance was measured with their paces.
Unfortunately, a rare glacier eruption occurred at Guxiang village in Nyingchi during construction and the huge ice blocks and stones destroyed the newly-built section.
Qi Shuchun, head of the construction team, and two builders went down into the barranca to study the geological conditions. They pressed themselves against the steep hill and climbed down into the dark and endless gorge.
They came up with an approach to building through the glacier after three hours of climbing and several more hours of work in ice-cold water.
A launch ceremony of the Sichuan-Tibet and Qinghai-Tibet highways was held on Dec 25, 1954, in Lhasa, capital city of Tibet.
People later re-measured the Sichuan-Tibet highway with satellite remote imaging and unmanned aerial vehicle mapping technologies, with results very little different from those calculated using the ancient compass and human paces.
The highways were the beginning of the country's infrastructure construction.
China now has more than 5 million kilometers of highway as well as the most high-speed railways, highways and ports for 10,000-ton ships in the world.
In addition to construction of domestic major projects, the company is also participating in infrastructure projects in other countries, contributing to international trade and local people's livelihoods.
(Executive editor: Wang Ruoting)