“ If the boom of the plaintiff should be extended up the river, within the limits of its plat and survey, the passage between its line of dolphins and the dolphins of the defendant on the other side of the stream would be so narrow as to block navigation. Moreover, it would be impracticable to operate both booms under such circumstances. If the defendant is permitted to operate its boom as intended, the boom of the plaintiff will receive only such timber from up the river as may escape from the boom of the defendant, and such as may be transmitted through that boom to the plaintiff. ”

“ Where there is a Federal law which it is claimed also applies to the subject and requires the consent of the Federal government, then there is a concurrent or joint jurisdiction of the state and national governments over the erection of a structure which obstructs navigation. ”