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392 COMBUSTIBLE MINERALS. fragile, emits an argillaceous odour when breathed on, and is of the specific gravity of 1-146. It burns with a considerable flame and smoke, and an almost insupportably fetid odour, with a crackling noise, leaving a residue of nearly half its weight, unaltered in lorm. Macerated in water, it becomes translucent, and its la- minas acquire flexibility. It occurs at Melili, near Syracuse, in a bed in secondary lime stone. 3 AMBER. Bernstein, W. Succin, H. Yellow Mineral Resin, M. Contains Carbon 80-59 70-68 Hydrogen 7-31 11-62 Oxygen 6-73—Drapier. 7-77—Ure. Sp. Gr. 1-0—1-1. H. = 2-0—2-5. In irregular nodules, masses, or grains, generally of a yellow or yellowish-white colour; sometimes reddish-brown. It is brittle, and yields easily to the knife; is occasionally transparent, always translucent; fracture more or less perfectly conchoidal, with a vitreous or resinous lustre. Resinous electricity easily produced Vnction; this property gave rise to the science of electricity, which was so called from HXsxrgov, the Greek name for amber. It yields by distillation an acid called the succinic acid, and leaves an extremely black, shining residue, which is employed as the basis of the finest black varnishes. It burns with a yellow flame, emits an agreeable odour, and leaves a light, shining, black coal. Is soluble in alcohol. The experiments of Sir David Brewster on the optical properties of amber, leave no doubt of the origin of this substance being derived from the vegetable kingdom, as the traces of regular structure indicated by its action on polarized light are not the effect of the ordinary laws of crys tallization by which mellite has been formed, but are produced by the same causes which influence the mechanical condition of gum arabic and other gums, which are known to be formed by the successive deposition and induration of vegetable fluids. I lie largest specimens of amber occur on the Prussian coast, w ere it is disengaged by the action of the waves, and cast ashore. a so occurs occasionally presenting very peculiar tinges of blue, on the Sicilian coast near Catania; imbedded in brown coal at Hasen Island in Greenland; in Poland, Prance, Italy, and many other countries; and occasionally in the beds of gravel in the neighbourhood of London, and on the coasts of Norfolk and Suffolk. Of those insects which have been origin- ally enclosed in amber, some have evidently struggled hard for their liberty, and even left their limbs behind them in the at-