4. Answers to formal complaints, and to amended complaints where leave to amend has been granted by the commission, must be made by defendants and served upon all parties to the proceedings. Any defendant failing to file and serve answer within the period prescribed by paragraph 1 of this section will be deemed in default, and issue as to such defendant will be thereby joined. 5. Answers to formal protests shall be optional with the party against the approval of whose application, or claim, or interest the protest is directed. 6. Answers to petitions in intervention filed and served upon leave granted by the commission shall be optional with the party in whose pending proceedings intervention is sought. 7. If a defendant satisfies a formal complaint, either before or after answering, a statement to that effect signed by the opposing parties must be filed with the commission, setting forth when and how the complaint has been satisfied. XXII. AMENDMENTS 1. Amendments to any protest, complaint, petition, or answer will be allowed or refused at the discretion of the officer of the commission before whom the proceedings are pending, subject in case of refusal to petition for reconsideration or review as provided in section X hereof. XXIII. CONTINUANCES AND EXTENSIONS OF TIME Continuances and extensions of time will be allowed or refused at the discretion of the officer of the commission before whom the proceedings are pending; or, if pending before the commission, at the discretion of the commission. XXIV. COMPLIANCE WITH ORDERS When an order has been issued by the commission directing performance of, or abstention from, specific acts or practices, the defendant, respondent, or other party named therein and against whom such order runs shall, on or before the date upon which such order becomes effective, notify the commission of compliance with such order, or, if the case be such, of its intention to refuse to comply. APPENDIX A CERTAIN DECISIONS OF THE COMMISSION UNDER THE FEDERAL WATER POWER ACT HAVING PARTICULAR REFERENCE TO PRACTICE AND PROCEDURE COMPLIANCE WITH STATE LAWS Section 9 of the Federal water power act does not require the Federal Power Commission to find that the applicant is the owner of any lands necessary to the construction of his project, or to adjudicate disputed water rights where the applicant has made such filings in a State office and received such consent from the State as may be provided by its laws. Chief Counsel to the Executive Secretary, November 21, 1921. Approved by the commission January 24, 1922. (Second annual report, p. 224.) DEPRECIATION: The authority of the Federal Power Commission to prescribe rules for accounting for depreciation is not limited to the provisions of section 10, subsection (c), of the Federal water power act, but extends to such accounting rules as may be necessary to ascertain net investment and other factors useful in the administration of the act with reference to any project; the term "depreciation " is used in the act in the sense of the exhaustion of capacity for service, or the current lessening in service value, due to the several causes set forth in the definition contained in Regulation 16 of the commission's rules and regulations; the words "depreciation reserves mean the credit balances of depreciation accounts created and maintained for the purposes contemplated by the act; the purpose or purposes for which such reserves are required by the act to be established and maintained are that there shall be available out of earnings, assets, or credits sufficient for offsetting the reduction in service value due to accruing depreciation, from whatever cause, and adequate for renewing or replacing, so far as respects their original cost, units of equipment, or of structures when their useful lives expire, in order that "at the end of any given term of years the original investment remains as it was in the beginning"; and the rules for accounting for depreciation as contained in Regulation 16 are consistent with the act and with other legislation of Congress and are necessary and proper for the purpose of carrying out the provisions of the act. Chief Counsel to the Executive Secretary, May 6, 1922. Approved by the commission July 26, 1922. (Second annual report, p. 226.) ACCOUNTS AND REPORTS It is not within the discretion of the Federal Power Commission to omit to prescribe the system of accounts and reports specified in section 4, subsection (f), of the Federal water power act; in so far as applicable the "classification of investment in road and equipment of steam roads, issue of 1914, Interstate Commerce Commission," is to be promulgated as a part of such system and it is not within the authority of the Federal Power Commission to waive the same; and the tentative draft of a system of accounting recommended by a committee of the National Association of Railway and Utilities Commissioners is inconsistent with these requirements and can not legally be adopted in toto by the Federal Power Commission in lieu of such requirements. Chief Counsel to the Executive Secretary, May 25, 1922. Approved by the commission July 26, 1922. (Second annual report, p. 244.) ALTERATIONS OF LICENSES Changes in project plans involving no substantial modification in the original scheme of development as authorized in a license, and corrections in or changes of the provisions of a license involving no substantial modifications of its original terms and conditions do not constitute alterations of the license within the meaning of section 6 of the Federal water power act so as to require the 90 days' public notice therein specified. Chief Counsel to the Executive Secretary, March 12, 1923. Approved by the commission April 30, 1923. (Third annual report, p. 223.) PROCEDURE AND PRACTICE IN REGULATING SERVICES, RATES, AND SECURITIES Answering certain questions with regard to the meaning of paragraph 2, section 20, of the Federal water power act requiring the administration of the provisions of that section to be in accordance with the procedure and practice of the interstate commerce act in so far as applicable: Held, That the procedure and practice referred to are the procedure and practice prescribed by the interstate commerce act in the regulation of corresponding matters under that act as amended; that the provisions of section 20a of the interstate commerce act are binding only in so far as they prescribe procedure and practice, and the instructions to carriers under that section in regard to issuance of securities, in so far as they are applicable and conform to the statute under which they were issued, may be followed by the Federal Power Commission in the regulation of corresponding matters under section 20 of the Federal water power act; and that the provisions of section 20 of the Federal water power act as to procedure and practice are limited to the administration of the provisions of that section, but the commission may prescribe the same procedure and practice in the administration of section 19 of the act. Chief Counsel to the Executive Secretary, May 11, 1925. Subject: Procedure and practice in regulating services, rates, and securities under section 20, Federal water power act. In your memorandum of April 1, 1925, you quote the second paragraph of section 20 of the Federal water power act and request my opinion by way of answer to specific questions which you submit. The questions, with the answer to each question thereunder, are as follows: Question 1. What, in the meaning of the paragraph quoted, is "the procedure and practice in fixing and regulating the rates, charges, and practices of railroad companies" in conformity with which this commission is to administer the provisions of section 20 of the Federal water power act? Answer. The first paragraph of section 20 provides as follows: "That when said power or any part thereof shall enter into interstate or foreign commerce, the rates charged and the service rendered by any such licensee, or by any subsidiary corporation, the stock of which is owned or controlled directly or indirectly by such licensee, or by any person, corporation, or association purchasing power from such licensee for sale and distribution or use in public service, shall be reasonable, nondiscriminatory, and just to the customer, and all unreasonable discriminatory and unjust rates or services are hereby prohibited and declared to be unlawful; and whenever any of the |