Letter, from Antoni van Leeuwenhoek to the Royal Society, dated at Delft Signed autograph Observations of spiders; their blood; of silk thread and its structure; a spider's sting; spinneret; laying eggs; young spiders 8 red-chalk figures attached Read to the Royal Society on 6 August 1701 English translation see EL/L3/30 Transcribed in JBO/10/226 Transcribed and translated in 'Alle de brieven van Antoni van Leeuwenhoek', edited, illustrated and annotated by Committee of Dutch Scientists, vol 13, p 317 English translation printed in 'Philosophical Transactions', vol 22, no 272, p 867 21 June 1701