Most Viewed

- Browns And The Cold Semi-neutral Grays Marrone Is Practically To
- Also Called Scarlet Chrome Is A Bright Chromate Of Lead Of An
- Black Chalk
- Composition Chemical Analysis Has Shown Several Of The Blues To Be
- Burnt Verdigris
- Belong The Dutch And Flemish Schools; The Sensible Which Aims At
- Less Known As English Red Prussian Red And Scarlet Ochre True
- Olive In Dark Green; Russet And Citrine In Dark Orange The
- Known Likewise As Raw Sienna Earth Terra Di Sienna &c Is A
- Root Of The Anchusa Tinctoria Commonly Known As Alkanet A Plant

Least Viewed

- Their Chief Source The Greens Consist Of Yellow Mixed With Copper
- Only That Of Extreme Light Objects Opaque It Follows That White Is To
- To Which The Various Appellations Have Been Given Of Thenard's Blue
- Distilled Verdigris Or More Properly Refined Verdigris The Best Is
- Red And Blue In The Proportions Of Five Of The Former To Eight Of
- Violet De Mars Purple Ochre Or Mineral Purple Is A Dark Ochre
- Uniform Colour Thus Composed Is The Citrine Colour Of Fruit And
- Also In The Olive Foliage Of The Rose-tree Formed In The Individual
- Asphalt Bitumen Mineral Pitch Jew's Pitch Antwerp Brown
- Mixture With Drying-oil Bitumen: The Latter Is Likewise Known As

Coal-tar Colours

Our work might be considered incomplete without some allusion to the
coal-tar colours, even though they are rather dyes than pigments, not
possessing sufficient stability for the palette. To avoid repeated
reference, we have preferred grouping them in this chapter, irrespective
of hue. Consequently, yellow, red, blue, orange, green, purple, brown,
and black, will be all comprised under the heading of coal-tar colours.

Previous to the year 1856 the colouring matters derived from coal-tar
were practically unknown. Until then, that black evil-smelling substance
was looked upon as almost worthless; but gradually the unsightly grub
emerged into a beautiful butterfly, clothed first in mauve and next in
magenta. After its long winter of neglect, there sprung from coal-tar
the most vivid and varied hues, like flowers from the earth at spring.
At a touch of the fairy wand of science, the waste land became a garden
of tropic tints, and colour succeeded colour, until the whole gamut had
been gone through. Never was transformation more dazzling or more
complete. The once despised refuse was now a valued commercial
product--indeed a trade in itself. Perfectly fascinated by the study,
chemists threw themselves heart and soul into coal-tar, and coal-tar
colours were to be seen everywhere.

It were beside our purpose to enter into the various stages through
which coal has to pass to become colour. Enough to state that to the
introduction of gas-light we are indebted for the acquisition of
coal-tar colours, the starting point for the production of mauve,
magenta, &c., being the manufacture of coal-gas. From the destructive
distillation of coal, coal-tar oil results; and from this are obtained
the products which yield the colours in question. Among these products
may be mentioned aniline, rosaniline, napthaline, chinoline, carbolic
acid, picric acid, &c., with their derivatives.

Of the fifty-one compounds furnished by the distillation of coal,
perhaps the most popularly associated with coal-tar colours is aniline,
to which we will therefore confine ourselves. Discovered in 1826, this





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Previous: Chica Red

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