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
- Thallium Orange
- Distilled Verdigris Or More Properly Refined Verdigris The Best Is
- Molybdenum Green
- 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

Red Chalk

The colouring matter of which is sesquioxide of iron, is used as a
crayon. Some specimens are excessively hard, so much so that they are
difficult to crush, even in an iron mortar; while others have the
consistence of the softest iron-ochres. They vary too in tint from a
fawn colour to the softest brick-red, occasionally being almost as
bright as a mixture of equal weights of vermilion and Venetian red. The
amount of iron oxide present has been found to range from four to
thirty-seven per cent, according to the depth and hardness of the
samples. When a specimen of red chalk tolerably rich, but not too rich,
in iron oxide is finely powdered and strongly ignited, it offers a
remarkable change of colour, becoming a dull sage-green. Perhaps this,
if it were permanent, might prove useful in foliage tints.





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