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الصفحة 353 - ... a consequence of the rule that the difference of the squares of the velocities of the ordinary and extraordinary rays within the crystal, is proportional to the product of the sines of the angles which the latter makes with the resultant axes. M. Biot was led to the discovery of this beautiful law by analogyf, and he afterwards observed that it was implicitly contained in the law proposed by Sir David Brewster. The term
الصفحة 11 - I assume this force to act under portions of the earth's crust of considerable extent at any assignable depth, either with uniform intensity at every point, or in some cases, with a somewhat greater intensity at particular points, as, for instance, at points along the line of maximum elevation of an elevated range, or at other points where the actual phenomena seem to indicate a more than ordinary energy of this subterranean action. I suppose this elevatory force, whatever may be its origin, to act...
الصفحة 1 - Notwithstanding' the appearances of irregularity and confusion in the formation of the crust of our globe, which are presented to the eye in the contemplation of its external features, Geologists have been able in numerous instances to detect, in the arrangement and position of its stratified masses, distinct approximations to geometrical laws.
الصفحة 116 - Their evident analogy to the property of a triangle " that the sines of the angles are proportional to the opposite sides", has suggested another form under which they may be put.
الصفحة 57 - ... to the causes to which we have been assigning such phenomena, could not be produced by successive elevations of different points, by the partial action of an elevatory force.
الصفحة 404 - Very often too, when sound is reflected, these suppositions will lead to sensibly correct results. On this last account, the problem has here been considered generally for all fluids whether elastic or non-elastic in the usual acceptation of these terms; more especially, as thus its solution is not rendered more complicated. One result of our analysis is so simple that I may perhaps be allowed to mention it here. It is this : If A be the ratio of the density of the reflecting medium to the density...
الصفحة 75 - Holme, there is a bed extending for a great wayi surmounted by a parallel series of the secondary strata in contact with it ; but, on a narrow inspection, innumerable veins are seen branching into the strata in every possible direction, illustrating in a very perfect manner the origin of at least one order of veins. In a second case, three beds of trap can be traced in a parallel direction for a considerable space, separated by the regular strata, when suddenly the whole unite into one mass. Had...
الصفحة 465 - ... that joint : if it lie within the cone spoken of, the structure will not slip upon that joint ; if it lie without it, it will. Thus the whole theory of the equilibrium of any structure is involved in the determination with respect to that structure of these two lines — the line of resistance, and the line of pressure. One of these lines, the line of resistance, determining the point of application of the resultant of the pressures upon each of the surfaces of contact of the system ; and the...