Letter, from Antoni van Leeuwenhoek to the Royal Society, dated at Delft Signed letter Examining the preparation of salts and their crystals; Leeuwenhoek repeats his theory about the causes of taste Original figures now no longer exist Transcribed and translated in 'Alle de brieven van Antoni van Leeuwenhoek', edited, illustrated and annotated by Committee of Dutch Scientists, vol 5, p 69 English extract printed in 'Philosophical Transactions', vol 15, no 173, p 1073 23 January 1685