“ And, of course, the converse is also true, that the Navy Department has no power to entitle an officer to receive sea pay by assigning him to duty which is essentially shore duty, and mistakenly qualifying it as sea duty. But there is no conflict between these rulings, and the conceded principle that, where an officer is assigned to a duty which is essentially a sea service, that he does not lose his right to sea pay whenever he is called upon to perform a mere temporary service ashore. ”

“ The government did not dispute at bar, however, that where an officer assigned to sea duty within the purview of the foregoing provision is called upon, without a change in his sea assignment, to perform merely temporary service ashore, he is entitled to sea pay. And this is in accord with the naval regulations, wherein it is provided:
' (1) Officers shall be entitled to sea pay while attached to, and serving on board of, any ship in commission under control of the Navy Department, the Coast Survey, or the Fish Commission. ”