There is a familiar saying of jurisprudence, that it is the part of a good judge to amplify his jurisdiction: _Boni judicis est ampliare jurisdictionem_. This maxim, borrowed from the horn-books, was originally established for the sake of justice and humanity, that they might not fail; but it has never been extended to other exercises of authority. On the contrary, all accepted maxims are against such assumption in other cases. Never has it been said that it is the part of a good presiding officer to amplify his power; and there is at least one obvious reason: a presiding officer is only an _agent_, acting always in presence of his _principal_. Whatever the promptings of the present moment, such an amplification can find no sanction in the National Constitution, or in that Parliamentary Law from which there is no appeal. Thus, which way soever we turn,--whether to the National Constitution, or to Parliamentary Law, as illustrated in England or the United States,--we are brought to conclude that the Chief Justice in the Senate Chamber is not in any respect Chief Justice, but only presiding officer; that he has no judicial powers, or, in other words, powers _to try_, but only the powers of a presiding officer not a member of the body. According to the injunction of the Constitution, he can _preside_, but this is all, unless other powers are superadded by concession of the Senate, subject always to the constitutional limitation that the Senate alone can _try_, and, therefore, alone can rule or vote on questions which enter into the trial. The function of a presiding officer may be narrow, but it must not be disparaged. For a succession of generations, great men in the law, Chancellors and Chief Justices, have not disdained to discharge it. Out of the long and famous list I mention one name of surpassing authority: Somers, the illustrious defender of constitutional liberty, unequalled in debate as in judgment, exercised this function without claiming other power. He was satisfied to preside. Such an example is not unworthy of us. If the present question could be determined by sentiments of personal regard, I should gladly say that our Chief Justice is needed to the Senate more than the Senate is needed to him. But the National Constitution, which has regulated the duties of all, leaves us no alternative. We are the Senate; he is the presiding officer,--although, whether in the Court Room or the Senate Chamber, he is always the most exalted servant of the law. This character he cannot lose by change of seat. As such he lends to this historic occasion the dignity of his presence and the authority of his example. Sitting in that Chair, he can do much to smooth the course of business, and to fill the Chamber with the spirit of justice. Under the rules of the Senate, he can become its organ,--but nothing more. EXPULSION OF THE PRESIDENT. OPINION IN THE CASE OF THE IMPEACHMENT OF ANDREW JOHNSON, PRESIDENT OF THE UNITED STATES, MAY 26, 1868.