 Crowning the top of the clock tower was the large bronze, mechanically-driven, rotating armillary sphere.In 1070, Su Song also compiled the "Ben Cao Tu Jing" (Illustrated Pharmacopoeia, original source material from 1058–1061 AD) with a team of scholars.This pharmaceutical treatise covered a wide range of other related subjects, including botany, zoology, mineralogy, and metallurgy.