improperly called gum copal, is a gum of the resinous kind brought from New Spain, being the concrete juice of a tree* which grows in these parts.* Rhizocarpus. It comes to us in irregular masses, some of which are transparent, and of different shades as to colour, from a light yellow to a deep brown. Some pieces are whitish and semitransparent. To the smell it is more agreeable than frankincense; but hath neither the solubility in water common to gums, nor in spirit of wine common to resins, at least in any considerable degree. By these properties it resembles amber; which has induced some to think it a mineral bitumen resembling that substance. In distillation it yields an oil, which like mineral petroleum is indissoluble in spirit of wine. Copal itself is soluble in the essential oils, particularly in that of lavender, but not easily in the expressed ones. It may, however, be dissolved in linseed oil by digestion, with a heat very little less than is sufficient to boil or decompose the oil. This solution, diluted with spirit of turpentine, forms a beautiful transparent varnish, which when properly applied, and slowly dried, is very hard and durable. This varnish is applied to snuff-boxes, tea-boards, and other utensils. It preserves and gives lustre to paintings, and greatly restores the decayed colours of old pictures, by filling up the cracks and rendering the surfaces capable of reflecting light more uniformly.