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

Ultramarine Red?

In Gmelin's Handbook of Chemistry it is remarked that "Hydrogen gas
passed over ignited ultramarine, colours it light red, from formation of
liver of sulphur, hydrosulphuric acid gas and water being evolved at the
same time." On most carefully making the experiment with a sample of
native blue (the variety referred to) we did not succeed in effecting
this change: no alteration to red or even to purple took place, the only
result being that the colour was entirely spoilt, having assumed a
leaden slate-gray hue. At our request, the trial was kindly repeated by
well-known chemists, who took every precaution to ensure success.
Several specimens of ultramarine were acted upon, but in no case was a
red or anything like a red obtained, the products ranging from a
slate-gray to a drab-grey. Sufficient hydrosulphuric acid gas was
evolved to blacken paper moistened with acetate of lead, a fact which
proved that the blue had lost some of its sulphur. Seeing that not only
no red was produced, but that no tendency to red was imparted, is it
possible the change described by Gmelin occurred under exceptional
circumstances? All conversant with chemical matters will admit that
results are obtained occasionally which cannot be repeated, owing it may
be to some slight difference in the materials employed, or some slight
variation of the process. Perhaps a link, considered of no importance
at the time and overlooked, has been lost, and thus the whole chain of
proceeding becomes useless. It is, therefore, within the bounds of
probability that the red ultramarine of the great German chemist was
furnished either by a peculiar specimen of blue, or by a modified form
of the method he gives. We have noticed the subject at some length
because if a red ultramarine, brilliant and durable, could be obtained,
the colour might prove of value. A permanent artificial compound
corresponding to French blue would certainly be an acquisition.





Next: Uranium Red
Previous: Tin Pink

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