than for the other, the total load on the foundation is less, and, consequently, the area of base required is smaller. Whether the excavation is wet or dry will make considerable difference, the former condition favoring reinforcing and the latter militating for plain concrete. Where the footing cannot be pumped out, it is rarely permissible to use reinforcement.

Sometimes in a long trestle it is doubtful whether to adopt reinforced- concrete piles with quite-shallow bases for the pedestals or to employ the cheaper wooden piles and sink the said bases to extreme-low-water elevation, in order to ensure that the wood shall always be saturated and never exposed to the air. In such a case, one or two pedestals should be designed by each method and their costs determined for comparison.