Letter, from Antoni van Leeuwenhoek to Henry Oldenburg, dated at Delft Signed autograph Notifying the Royal Society about an error in experiments of evapourating vegetable infusions (EL/L1/11); observations of wine-vinegar; concerning Leeuwenhoek's invention of an areometer, although he saw that Robert Boyle had constructed a similar glass in an article in 'Philosophical Transactions' (volume 10, page 340) Transcribed and translated in 'Alle de brieven van Antoni van Leeuwenhoek', edited, illustrated and annotated by Committee of Dutch Scientists, part 1, p 328 For summary see 'The correspondence of Henry Oldenburg', ed and trans by A Rupert Hall & Marie Boas Hall, vol 12, p 87 20 December 1675