. Edinburgh New Philosophical Journal. 304 M. Ami Boue on the Palceohydrography i in the North American point, we can estimate the value of the low shore, when we know the elevation of the high and steep chain, but the sea should have on both sides the same depth, which is frequently not the case. The sea can be deep on one side, and shallow on the other, or deep or shallow on both. For this reason, the normal depth of the sea will al- ways better suit for the calculations. When a rigid part of the earth was elevated, vaults were produced, or in other words, elevations and subsidences, ac- cor
. Edinburgh New Philosophical Journal. 304 M. Ami Boue on the Palceohydrography i in the North American point, we can estimate the value of the low shore, when we know the elevation of the high and steep chain, but the sea should have on both sides the same depth, which is frequently not the case. The sea can be deep on one side, and shallow on the other, or deep or shallow on both. For this reason, the normal depth of the sea will al- ways better suit for the calculations. When a rigid part of the earth was elevated, vaults were produced, or in other words, elevations and subsidences, ac- cording to the principle of the see-saw motion. If the value of such an elevation above the level of the sea is found, it is easy to obtain that of the subsidences under water, because both values are determined by an equal angle around a fixed point. A country might have been subjected to a simple see-saw like motion, as England for instance, where one shore is high and hilly, and the other flat, with subsidences in the Northern sea. The middle of an island can have been vaulted with a kind of double see-saw motion, of which the two elevated extre- mities represent the middle of the vault. The subsidences of both sides under the sea-level would equal the height of the vault above the sea-level. The variation in the position of the highest part of the elevation changes nothing in the results, the triangles which are to be constructed on both sides, above and below the sea- level, will only become more and more unequal the more the greatest elevation is placed further from the middle part of the observed land on one or other side. If two tijjangles represent the vault above the sea-level, and their base be that level, and if we lengthen these lines on both sides of their relative value in the triangles, and if we do the same with the two lines which descend from the middle of the vault, till the sea-shore on both sides become, through this construction on each side under the sea, s
Size: 1936px × 1291px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookcollectionbiod, bookdecade1850, bookyear1853
