is the nature of the earth to attract and keep things.’ His works are
  Brahmasphuta Siddhanta and Khanda Khadyaka.
  Perhaps one of the most seminal developments in the field of science was
  the pronouncement of the atomic theory by the Vaisesika school of
  physicists.
Medical and Other Sciences
Metallic preparations for the purpose of medicine and references to the use of
mercury and iron by Varahamihira and others indicate that much progress
was made in chemistry. The Navanitakarn was a medical work, which is a
manual of recipes, formulae and prescriptions.
    Hastyayurveda or the veterinary science, authored by Palakapya attests to
the advances made in medical science during the Gupta period.
POLITICAL AND CULTURAL HISTORY OF
THEIR SUCCESSORS
Harshavardhana (AD 606–47)
               SOURCES FOR HARSHA’S PERIOD
  Bana was the court poet of Harsha and the author of Harshaeharita,
  Kadambari and Parvatiparinay.
  Hiuen Tsang was the Chinese pilgrim who visited India in the seventh
  century AD. Both deal with Harsha’s .wars but in a vague and general
  manner and sometimes make us even more confused. Above all, they
  sometimes give an exaggerated account of Harsha.
  Harsha’s dramas such as Ratnavali, Nagananda and Priyadarsika give us
  information about the political conditions in those days.
  Nausasi Copper Plate gives us information about Harsha’s successful
  expedition against Valabhi.