[…] I ſhall add, that proſecuting a hint a happened to meet with in the diſcourſe of a wandering chymiſt, I practiſed a way ſo to defecate the dark and muddy oil of amber drawn per ſe, that a pretty proportion of it would come over ſo tranſparent and finely coloured, that the experiment did not a little pleaſe thoſe I ſhewed it to.
1744, Robert Boyle with Thomas Birch, edited by Thomas Birch, The Works of the Honourable Robert Boyle: In Five Volumes : to which is Prefixed, the Life of the Author, volume 1, compilation of Certain phyſiological eſsays and other tracts written at diſtant times, and on ſeveral occaſions by the honourable Robert Boyle ; wherein ſome of the tracts are enlarged by experiments and the work is increaſed by the addition of a diſcourse about the abſolute reſt in bodies. by Robert Boyle, part VI: Certain Physiological Essays, and other tracts written at diſtant Times, eſsay 7: The Hiſtory of Fluidity and Firmneſs, the ſecond part: of Firmneſs, page 265