Seismic Instruments
“The invention is a source of pride for the Chinese.”
For the past two weeks the Sheraton Hotel in downtown Chengdu has graciously served as the NPR Chengdu Bureau. In that time I've gotten pretty accustomed to the layout of the hotel lobby and two items particularly have really captured my attention.
Photo by Brendan Banaszak, NPR
On each side of the main doors stands a mysterious looking, egg-shaped object mounted on a pedestal. The metal egg is about two feet high. Attached to it are eight ornate metal dragons spaced equally around the circumference. The dragons point toward the floor. Each has a little ball clenched in its mouth. Beneath each dragon sits a copper toad with its mouth wide open as if in mid-croak. At first glance, the objects seem to be a slightly kitschy attempt to give a very western looking hotel lobby a taste of the Orient. In actuality, they once served a slightly more relevant purpose.
As almost every Chinese school child can tell you, they are models of Didong Yi, the world's first earthquake detection device.
Invented by the Chinese mathematician, astronomer, and national hero Zhang Heng in the second century AD, the contraption could supposedly detect an earthquake, even hundreds of miles away from the epicenter. The shaking of the ground triggered a complicated system of a pendulum and levers that caused a ball to drop from the mouth of one of the dragons into the open mouth of the toad beneath it. Whichever dragon dropped the ball represented the direction where the quake occurred.
The invention is a source of pride for the Chinese. Working reproductions have been gifted to foreign nations; it was even minted on a commemorative gold coin.
Photo by Brendan Banaszak, NPR
The hotel management tells me the objects were part of a design thought up by a Feng Shui master when the hotel was built 9 years ago. The hotel's Director of Food & Beverage tells me that he personally thinks the good fortune brought by this lay-out was part of the reason the hotel was "not badly affected" by the earthquake.
The two ancient earth quake detectors in our hotel lobby aren't functional and even if they were they would provide little comfort to the people of Chengdu. There is no question as to where and when the May 12th earthquake occurred. What the people of Sichuan province really want is a way to detect accurately when future earthquakes might strike before they happen. Zhang Heng never invented that machine, and so far modern science has not done much better.
--Brendan Banaszak
8:43 AM ET | 05-22-2008 | permalink







