While working in the Bureau of Astronomy, Shen Kuo's interest in archaeology and old relics led him to reconstruct an armillary sphere from existing models as well as from ancient texts that could provide additional information. Shen used ancient mirrors while conducting his optics experiments. He observed ancient weaponry, describing the scaled sight devices on ancient crossbows and the ancients' production of swords with composite blades that had a midrib of wrought iron and low-carbon steel while having two sharp edges of high-carbon steel. Being a knowledgeable musician, Shen also suggested suspending an ancient bell by using a hollow handle. In his assessment of the carved reliefs of the ancient Zhuwei Tomb, Shen stated that the reliefs demonstrate genuine Han Dynasty (202 BC–220 AD) era clothing.