Extract of letter, regarding the preparation of caerulei prussiaci sent to John Woodward Letter in English from unknown sender (name scratched out) to Woodward regarding the history and making of caerulei prussiaci [Prussian blue] dye, and requesting that his paper be communicated anonymously. Appended to the letter is instructions to make the dye, written in Latin. Subject: Chemistry Latin portion of letter published in Philosophical Transactions as 'Præparatio cærulei prussiaci ex germaniâ missa ad Johannem Woodward, M. D. Prof. Med. Gresh. R. S. S'. Written in Lips [Leipzig, Saxony, Germany]. Read to the Royal Society on 9 January 1723 [1724]. 17 November 1723