Figs. 4, 5, 6, and 7 refer to vertical rectangular walls backed by sand, except in the case of Fig. 5, where the filling was macadam screenings. The surface of the filling was horizontal in each case. To give briefly in detail the quantities pertaining to each wall, the following symbols will be used:
and
are positive when the resultant on the base strikes within the base, otherwise they are negative.
[Fig. 4] represents Lieut. Hope’s wall of bricks laid in wet sand:
,
