Besides the seismograph, what else did Zhang Heng invent?

The leaky astrolabe is a water-borne elephant. Use a copper ball with a diameter of more than four feet, which is engraved with 28 nights, Chinese and foreign officials, yellow equator, north and south poles, 24 solar terms, constant display circle and constant hidden circle to form an elephant, and then use a set of rotating machinery to combine the elephant with the clepsydra. The elephant is controlled by running water from a leaky kettle to make it rotate synchronously with the celestial sphere, thus showing the Sunday visual movement of the starry sky, such as the appearance of stars and the transit of the sun. It also has a subsidiary organization called Ruilun Cai Ming, which is a mechanical calendar, connected with elephants by transmission devices. From the beginning of each month, a leaf is born every day; Drop a leaf every day after half a month. Among them, the second-class clepsydra used is the earliest known record of the second-class clepsydra.

Swiss wheel pod

Ruilun pod is an automatic calendar created by Zhang Heng. It imitates the characteristics of strange trees and pods in mythology. Through the action of running water, a leaf appears from the first day of each month to the full moon, with 15, and then one leaf is collected every day until the end of the month. This myth reflects the progress of astronomical calendar in the era of Emperor Yao. Zhang Heng's mechanical device was invented under the inspiration of this myth. It is said that "the moon is empty and rises and falls according to the calendar", which is equivalent to the date display in today's watch.

Compass car

The compass made by Zhang Heng is composed of two-wheeled unicycle by using mechanical principle and gear transmission. The trunk adopts a gear system with automatic clutch, and a woodcut fairy is placed on the upper layer of the trunk shell. No matter which direction the car rotates, the woodcut fairy's outstretched arm points south.

Metric drum car

The rice drum car created by Zhang Heng is a machine used to calculate mileage. According to "Notes on Ancient and Modern Times", "I remember that the car inside was on the second floor, with Woodenhead. One mile played drums on the lower floor, and ten miles made bracelets on the upper floor". The manufacturing method of drum car in Ji Li is the same as that of South Guide Car, and the principle of differential gear used is 1800 years earlier than that in the west.

Du Fei woodcarving

Zhang Heng's solo woodcarving is a glider design that imitates birds soaring in the sky.

relief map

Zhang Heng also studied geography. According to his research and investigation, he drew a topographic map. Zhang Yanyuan's Records of Famous Paintings in the Past Dynasties (Volume III) in the Tang Dynasty said: "The balance was used as a topographic map, and it still existed in the Tang Dynasty.