The Manufacturer and Builder 2, 1884
- Is there a green pigment that is not poisonous? or much less hurtful than the copper pigments? - B. J. A., Shippersburg, Pa.
Answer. We know of none that are entirely harmless. The least harmful is that suggested by Casall. It is prepared by calcining an intimate mixture of one part of potassium bichromate and three parts of baked gypsum. A grass-green mass is obtained, which, on boiling with water, or mixing with dilute hydrochloric acid, produces a fine powder of intense green color.
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