from The Century Dictionary.
- noun A blue substance used in dyeing, originally produced from the tar of beech-wood.
from the GNU version of the Collaborative International Dictionary of English.
- noun (Chem.) A dark blue substance obtained from wood tar. It consists of hydrocarbons which when oxidized form the orange-yellow eupittonic compounds, the salts of which are dark blue.
from Wiktionary, Creative Commons Attribution/Share-Alike License.
- noun organic chemistry A dark blue
dyestuff, the first to be commercially produced.
from Wiktionary, Creative Commons Attribution/Share-Alike License
Like indigo, pittacal is believed to contain nitrogen, but its ultimate composition has not been accurately determined.
The mode of separating pittacal has not been clearly described.
Our object in noticing this blue has been two-fold: first, to direct attention to wood-tar as a possible source of colour; and secondly, to point to pittacal as a possible substitute for indigo, possessing greater durability.