“ United States, 176 U.S. 221, 20 S.Ct. 376, 44 L.Ed. 443, this court held that where the proper construction of a statute is clear, the duty of an officer called upon to act under it is ministerial in its nature and may be compelled by mandamus. The opinion points out (page 231 of 176 U.S., 20 S.Ct. 376, 379) that every such statute to some extent requires construction by the officer; that he must read the law and, therefore, in a certain sense, construe it in order to form a judgment from its language what duty he is required to perform. ”

“ If the law direct him to perform an act in regard to which no discretion is committed to him, and which, upon the facts existing, he is bound to perform, then that act is ministerial, although depending upon a statute which requires, in some degree, a construction of its language by the officer. ”

“ The disbursing officer to whom the voucher was presented for payment, therefore, is simply a subordinate of the Chief of Finance, subject to his control and direction, and the suit was properly brought against the latter. The purpose of the suit was to control the action of the Chief of Finance, that is, to compel him to pay or cause to be paid the voucher in question. The disbursing officer as the mere agent of his superior officer is not an indispensable, although he might have been joined as a proper, party. ”