Ключевые слова: acid, analysis, ancient, antique, art, artwork, black, brownish, bundle, calcium, carbon, chemical, chemistry, compound, crystal, drawing, engraved, engraving, etching, form, heterocyclic, historic, history, hydrochloric, hydrogen, irregular, medical, microscope, nitrogen, old, oxalate, picture, pigment, quadrate, rhombic, roset, science, urates, uric, urochrome, uroerythrin, vintage, whetstone, white, yellow,