ISBN: 1236986504

[EAN: 9781236986504], Neubuch, MASSACHUSETTS. GEOLOGICAL SURVEY,SUBJECTS, This item is printed on demand. Paperback. This historic book may have numerous typos and missing text. Purchaser… Plus…

[EAN: 9781236986504], Neubuch, MASSACHUSETTS. GEOLOGICAL SURVEY,SUBJECTS, This item is printed on demand. Paperback. 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. 1841 edition. Excerpt: . . . forms are produced; but the seams run in all directions. I have not observed any case where the seams reach to the surface of the nodule. The outer portion, from half an inch to an inch thick, is compact gray iron stone An examination of these nodules, leads one at first almost irresistibly to the conclusion, that they must have been once in a melted state, and suddenly cooled at the surface: and the glazed iron-black appearance of their internal surface, tends to confirm this opinion. And yet, I doubt whether it is necessary to evoke the god of fire for a solution of this phenomenon. For the mere desiccation of nodules, containing so much argillaceous matter, will, it seems to me, adequately explain the appearances. Of course the external portion would first part with its moisture and become solid: and as the water gradually escaped subsequently from the interior, the shrinking would produce fissures within; since the already compacted crust would not permit the compression of the whole mass. And as to the shape of the pieces, resulting from the shrinkage, it seems to me that if the nodule be spherical, the fissures will coincide essentially with planes passing through the center of the sphere. (See No. 126. ) But if the shape be that of a flattened ellipsoid, the greatest shrinkage must take place in the direction of the plane, which coincides with the two longest diameters of the ellipsoid: and, therefore, most of the fissures will be made perpendicular to that plane, so as to produce columnar masses; although there will be a proportionable shrinkage in adirection perpendicular to the plane above mentioned, which will produce at least one termination to the columns: and all the specimens which I The existence, sometimes, of lignite in. . . This item ships from La Vergne,TN.<