Tyrian purple 520 nm, which is green). It is believed that the intensity of the purple hue improved rather than faded as the dyed cloth aged. Vitruvius mentions the production of Tyrian purple from shellfish. In his "History of Animals", Aristotle described the shellfish from which Tyrian purple was obtained and the process of extracting the tissue that produced the dye. Pliny the Elder described the production of Tyrian purple in his "Natural History": The most favourable season for taking these [shellfish] is after the rising of the Dog-star, or else before spring; for when they have once discharged their waxy secretion,
What Bird is That? Edition What Bird is That?" was published by Australia's Heritage Publishing in 2011, the latest release of Cayley’s “big bird book” complete with Lindsey’s revisions. It is 832 pages, features 769 birds and includes all 460 of Cayley’s full-colour paintings, many showing groups of related birds. New to this edition was an accompanying e-book "What Bird Call is That?", which identifies and illustrates 101 birds from "What Bird is That?", as well as providing sound files of each featured bird’s distinctive call. The sound files were provided by David Stewart. "What Bird is That?" plays a central role in Australian