If "the President and his Cabinet" had consulted the Principia Club papers more, and Southern rebels less, it would not have taken them half of their Presidential term to learn that rebel promises are of no account whatever, for they would have discovered abundant evidence of their utter worthlessness. As "federal bayonets" are now so popular in _rebel_ hands, and getting to be so useful to put down _Republicanism_ in South Carolina, perhaps our verdant President, in his "_surprise_," may break the shackles with which he was voluntarily bound, and use "federal bayonets" to put down _rebellion_. At all events, he ought to obey the United States Constitution he has sworn to support, which tells him he "shall guarantee to every State in the Union a republican form of government." If he hasn't given away all his "federal bayonets" to the rebels, is it not about time for our commander-in-chief to use them in South Carolina? (See Principia Club Papers No. 7, pp. 152-5: The Southern Policy.) [Special Despatch to the Boston Traveller.] Washington, D. C., Oct. 18.--The President has taken steps, through the proper officers, to have the outrage perpetrated at Sumter, South Carolina, investigated, with a view of ascertaining who is responsible, and whether or not there has not been an open violation of the United States laws. District-Attorney Northrup has the case in charge, and will, said a member of the Cabinet to your correspondent to-day, make an energetic investigation of the outrage and report the facts promptly. There is no reason to doubt that he will do his whole duty and make a fearless investigation of the affair, which, according to the Democratic account, was brutal in the extreme. The Administration, said the Cabinet Minister further, will see that the rights of the colored people in South Carolina are maintained, and to this end will, if necessary, go to the full extent of the United States laws. We may be too faithless in this matter, we hope we are, but when "investigations" shall result in the _punishment of criminals_, instead of their protection from further molestation, we may have more confidence that justice will triumph in rebeldom. VIRGINIA COMES NEXT. "President Hayes, who is attending an agricultural fair at Winchester, Virginia, made a hard money speech yesterday, and quoted Washington, Jefferson, Madison, and other distinguished Virginians in favor of sound money."--_Traveller, Oct. 17_. While the President was making stump speeches in Winchester, in the direct line of civil service reform, as he understands it we suppose, the shot-gun brigade were at Hicksford demonstrating the fruits of his Southern policy. The "Traveller" states this case in the following strain of sarcasm.