The framework of the sheeting should be placed with a cross brace for each end of each ranger and a cross brace for the middle of each ranger. If the ends of two rangers rest on the same cross brace an accident displacing one ranger will be passed on to the next and might cause a progressive collapse of a length of trench, whereas the movement of an independently supported ranger should have no effect on another ranger. The cross braces should have horizontal cleats nailed on top of them as shown in Fig. 107 to prevent the braces from being knocked out of place by falling objects. In driving vertical sheeting a vacant place will be left behind each cross brace corresponding to the original block placed to hold the ranger away from the bank. This is an undesirable feature in the use of vertical sheeting. It is ordinarily remedied by slipping in planks the width of the slot and wedging or nailing them against the convenient cross bracing. In extremely wet trenches, after all other pieces of vertical sheeting are in place, the original cleat behind the cross brace can be knocked out and a piece of sheeting slipped into this opening and driven. Care must be taken in this event not to drive the rangers down when driving the sheeting. If the bracing begins to drop, it should be supported by vertical pieces between the rangers and resting on a sill at the bottom of the trench. [Illustration: FIG. 110.—Steel Clamp for Pulling Wood Sheeting. ] =155. Pulling Wood Sheeting.=—Wood sheeting is pulled after the completion of the trench by a device shown in Fig. 110. In wet trenches where the removal of the sheeting would permit a movement of the banks, resulting in danger to the sewer or other structures, the sheeting should be left in place in the trench. If sufficient saving can be made the sheeting is cut off in the trench immediately above the danger line, usually the ground water line. The cutting is done with an axe or by a power driven saw devised for the purpose.