The colourproducing reagent is added and the tints compared.
This beautiful material presents a great diversity of tints, but a rich hyacinth red is common.
None of the Petrels are endowed with any brilliant colouring - sootyblack, grey of various tints (one of which is often called "blue"), and white being the only hues the plumage exhibits.
While the price of the finest tints of rose pink may range from go to £1 20 per oz., ordinary red-coloured small pieces sell for about £2 per oz., and the small fragments called collette, used for children's necklaces, cost about 5s.
The African golden-moles (Chrysochloris), the desmans or water-moles (Myogale), and the West African Potamogale velox, are remarkable as being the only mammals whose hair reflects those iridescent tints so common in the feathers of tropical birds.