Page:Great Neapolitan Earthquake of 1857.djvu/190

142 cylinder, whose height above the horizontal plane of fracture is $$a$$, then $$f = \frac{a}{2}$$. If $$\mathrm{L}$$ be the modulus of dynamic cohesion—a coefficient representing the length of a prism of the same material, whose weight is equal to the force upon the unit of surface, if suddenly applied, which is sufficient to tear it directly asunder,—then or

Here therefore

Here therefore