In 1804 he had published an article on observations of the moon, and in 1806 he published naval charts of the harbour at Salem and several other harbours.
Sa 1804 niya na nai-publish ng isang article sa mga obserbasyon ng buwan, at sa 1806 siya nai-publish ng hukbong-dagat tsart ng mga silungan at Salem at maraming iba pang mga harbours.