The Americana; a universal reference library, comprising the arts and sciences, literature, history, biography, geography, commerce, etc., of the world Volume 1 - Softcover
Synopsis
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1912 edition. Excerpt: ...namely, the presence of from 5 to 8 per cent of succinic acid. Its composition is represented by the formula Gohmo. It occurs in irregular masses, usually of small size but sometimes weighing up to 15 or 18 pounds. It has a yellow color, resinous lustre and conchoidal fracture. Its hardness is 2 to 2.5 and specific gravity 1.05 to I.I. Along the shores of the Baltic Sea, especially in East Prussia, mining for amber has been carried on for two centuries. In this region shafts are sunk through a superficial stratum of marl and sand, a bed of lignite with light sands and gray clays, and finally a layer of green-sand, 50 to 60 feet thick. All of these strata contain amber, but in the lower portion of the green-sand there is a stratum 4 to J feet thick of "blue earth9 in which amber nodules occur so abundantly that 50 or 60 square rods yield several thousand pounds. This "blue earth" stratum extends out under the sea and there the amber is freed and cast upon the shores by the waves, especially after the autumnal storms. Numerous other localities are known, but none are so prolific. In the United States amber-like resins have been found in the green-sand formation of Martha's Vineyard, Harrisonville, N. J., and elsewhere. Pliny declared amber to be "an exudation from trees of the pine family, a conjecture that proves to be correct. The _ fact that it was at one time fluid or nearly so is established by its occasional inclusion of insects; and its antiquity is also established by the fact that most of the species of insects so included are now extinct. Amber becomes strongly electrified when rubbed, and the power that it then possesses, of attracting light bodies to itself, was probably considered by the ancients to be the...
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