We do not see how the decree appealed from can be reversed. There are four witnesses who testified as to the alleged collision. They are flatly opposed to each other (two to two), with no theory which can harmonize their conflicting stories. The District Judge who saw them all states squarely that he believed two of them and, inferentially, that he did not believe the other two. We can find nothing in the record to convince us that he was mistaken in his judgment' of the value of their testimony.

The decree is affirmed, with costs.