Girigocha, a Wagon for Distance Measurement

'Girigocha' is a wagon which is used for measuring distances by the sound of a drum or a gong when predetermined distance is moved. When the wagon wheel with circumference of about 3 meter rotates 12 times, the lower wheel rotates once through the saw teeth at the bottom of the wagon, measuring about 36 meters. Also when the lower wheel rotates 15 times through the middle saw teeth, the middle wheel rotates once, measuring 540 meters, and when the middle wheel rotates 10 times, the upper wheel rotates once through the upper most saw teeth, measuring 5.4 km. Girigocha measured the distance of 1 degree of longitude of the earth as 108km which is not too different from today's reference distance of 111km.