Inside a magnetized body, B is the force that would be exerted on a unit pole if placed in a narrow crevasse cut in the body, the walls of the crevasse being perpendicular to the direction of the magnetization (Maxwell, § § 399, 604); and its numerical value, being partly due to the free magnetism on the walls, is generally very different from that of H.
When on Dec. 14 1912 Ninnis, with his sledge and dogs, broke through the snow covering of a crevasse of enormous depth and was instantly killed.
The work required to produce this crevasse is twice the product of the tension and the area of one of the faces.
If we now suppose the crevasse produced by direct separation of its walls, the work necessary must be the same as before, the initial and final configurations being identical; and we recognize that the tension may be measured by half the work that must be done per unit of area against the mutual attraction in order to separate the two portions which lie upon opposite sides of an ideal plane to a distance from one another which is outside the range of the forces.
Farther, the stream passes through a crevasse in the trap rock and has a sheer fall of 70 ft.
In the tremendous crevasse through which it sweeps round west, north and west again down to the western terraces, where it passes from Abyssinian to Sudan territory.
At the south-east corner the rim of the crater is, as it were, breached by a deep crevasse through which the Abai escapes, and here develops a great semicircular bend like that of the Takazze, but in the reverse direction - east, south and north-west - down to the plains of Sennar, where it takes the name of Bahr-el-Azrak or Blue Nile.