is constructed during the Kushan period. It is now kept at Lahore Museum, Lahore. Inventions, discoveries, introductions 105: Cai Lun of China invents paper. 125: Zhang Heng of China invents the world's first water-powered armillary sphere. 132: Zhang Heng of China invents first seismometer to detect the cardinal direction of earthquakes. Ptolemy compiles a catalogue of all stars visible to the naked eye. He also compiles three of the most influential books in western history: the Almagest which becomes the basis for western and Middle Eastern astronomy until the time of Nicolaus Copernicus and Johannes Kepler. the astrological treatise, Tetrabiblos. the Geographia. Hindu number system :It was developed in the Indian subcontinent between the 1st and 6th centuries CE. Carding devices: The earliest evidence for using bow-instruments for carding comes from India. References 1st millennium 02nd century