Nineteen members of Congress (says the Charleston Mercury) out of seventy or eighty, from the South, have put out the address which we publish in our columns to-day. It purports to be addressed to “the National Democracy;” but, in reality, it is addressed to the seceding delegates from the Charleston Convention. It proposes to the seceding delegates that they shall return to the adjourned Convention to meet at Baltimore, and shall abandon the Richmond Convention.

The proposition, in our judgment, is as insulting as it is impertinent. It is not only a proposition to eat up their words, but to swallow themselves, and to leave nothing behind them but the stench of disgrace and infamy. How honorable men could make such a proposition to others, is only possible, we suppose, in the reeking atmosphere of Washington.

But the proposition is not only insulting; it is impossible in performance. These gentlemen must know that in two States, at least, the contingency of their delegates leaving the Convention was anticipated, and that they were instructed to withdraw from it. Their duty is discharged. Their commission is ended, and they are no longer delegates.

The above extracts from the Montgomery (Ala.) Weekly Mail may be taken as a fair sample of the reasoning by which the re-union of the Democratic party is to be first denounced and then rendered an impossibility. Every effort to unite a party formed purely for temporary purposes, to secure an election of good officers and the temporary administration of Government, is treated as a question effecting a revolution in the confederacy, or the reconstruction of the political system of the country. The country is not looking to the revision of the Constitution or to the inauguration of a new form of Government through the agency of the Democratic party, or to make either by the nomination or election of a candidate for the Presidency. The people had no such objects in forming the Democratic party; they had no such design in calling the members of the party into general convention; they never looked with any such view to the election of delegates to Charleston, or to their re-assembling at Baltimore. Their object in the creation and regulation of the party was to control and regulate the administration of the Government under the Constitution and in the Union. When the federative system failed, or the Government was incapable of being made to fulfil its purposes and perform its functions, then the people, and not a party, were to be appealed to to remedy the ills of a country, the political institutions of which were too defective to promote their happiness or protect their interests.

The difference between us and the Southern seceders is, that they look to a difference on every question affecting our rights as a reason for breaking up a mere party organization. Now, we consider that the causes for forming and maintaining party organizations are limited in number and not very great in extent. A party is but a mere piece of machinery to aid in directing the actual temporary movements of the officials of government. The party has nothing to do with the construction or demolition of the political system established by the people. It is only to be destroyed, in our judgment, when one can be formed better calculated to direct the action of the acting officers of government. When evils so severe and dangerous come upon the country as to demand the destruction of government or the adoption of revolutionary measures, then other and new agencies are to be called into being by the popular will. Party associations and all the regular agencies of an established polity are certain to be set aside in such a contingency. Do the seceders consider this such a crisis? We conceive not. Their action does not show that they do. They propose to break up the Democratic party organization and to form a new one, with what view? Why, to contend for the election of a President and Vice President. They design to influence the action of a government elected, maintained, paid, and controlled by the present Northern and Southern States, possessed of identically the same powers, conferred by the same charter, as those under which the present Administration acts. They pretend not to seek for a new limitation of powers for the Executive; they design to make no change in the fundamental law, or in the relation of sections; to put no additional restraint on the power of the majority, nor in any manner to give one particle of additional security to persons or property, other than can be obtained by the election of patriotic men to executive and legislative offices entertaining sound views on constitutional questions and animated by a devotion to the maintenance of the just rights of citizens and States. This is their design in forming a new party.—They design to do nothing more by their party revolution than to affect the administration of the Government to be elected for the four years of its existence. They design to create no new safeguards for liberty—no new defenses for rights of property—no new guarantees for State sovereignty. They intend to try, through a new party, to get possession of the Federal Government and its patronage and power. They have no design beyond this; they avow none, and in good faith they can have no ulterior and unexplained purposes beyond these—the election of the Government officers and the direction of their practical action during their terms of office. They cannot, in honesty, be attempting to break up a party organization by their secession for the covert purpose of electing a worse set of officials, to necessitate a social and political war, without announcing their object to the people.

If we are right, and the object of forming and preserving the Democratic and other party organizations is to secure the election of officers and the control of their conduct, it is obvious that the views which separate party friends must have a direct and almost exclusive reference to attaining these objects. Now, do the advocates of this continued war in the Democratic party—those opponents of any reconciliation between its dissatisfied sections—hope, design, or wish to accomplish, these objects through the disruption of the old, or formation of the new party?—Every man who reads, or can make a common arithmetical calculation, knows they do not. Then, we say, as far as the direction of the action of government is concerned, and securing the purposes for which alone the creation of the party organization is either required or justified, this movement has no apparent reason to support it. And we are confirmed in the opinion by the needless and unprovoked incivility with which the discussion is conducted by the extremists on both sides.

We come now to consider the obstacles presented in the articles we quote to a reunion of the Democratic delegations. First, it objects that the seceding delegations cannot appear in the Baltimore Convention without eating “their own words.” Now, if the Convention had finished its work—if the questions of policy and principle had been really and definitely settled—if the Convention were over, passed, gone, and its work perfected, there would be some reason for this. But not only every politician, but every man of full age, who has not had a custodian appointed by the courts to take care of him and his affairs, knows that not one act of the Democratic Convention which assembled in Charleston on the aid of May [April] last, has one particle of authority attached to it, no motion that was passed, not one resolution that was adopted, not one principle that was announced, is as yet a part of the acts of that Convention. It is a body now in being, its action purposely undetermined, its session deliberately and considerately continued, its decisions wisely and properly unannounced, because they were not made.

The recess taken by the Convention for more than a month was to give men of common opinions on public affairs an opportunity of conferring together and devising some means of concentrating the energies of the true friends of the constitutional rights of the States and property-holding citizens. We say, in all kindness, to the editors of the Mail and the Mercury that they can afford to reason, and dispense with such phrases as “impertinent,” and “insulting,” and “insolent,” and “base,” to a proposition made by such men as have signed the address to the Democracy of the country. Although these gentlemen happen to hold position assigned them by enlightened constituencies of their several States, they are not necessarily to be vituperated even by the petulant and corrupt little office hunters who never expect to get office under an administration in which one of them has influence. The editors of the Mail and the Charleston Mercury belong to a different and higher class than the wretched creatures who creep into small offices by treason to men and neighborhoods, whose weapons of offence are loathsome vituperation and transparent mendacity, and whose labor of love is to do the dirty works of service which honest men can scarcely believe is ever performed. The editors of the Mail and Mercury have no reason to assail others who are really as deeply interested as they in the maintenance of Southern rights, and who have proved by a life-long action that they are as true to the South, and as good republicans and surely as tolerant gentlemen as they.

The recommendation of the nineteen may not accord with the views of those who seek to sever the Democratic party because it is the “strongest ligature which binds the Union,” but it does accord with the feeling, sentiment and objects of those who wish that the government shall be controlled by friends of the South, and not by Black Republicans. It will meet the approval of those who wish the people to be called directly to meet the issues with their Northern assailants, and not to be drawn to it by indirection and without preparation.