Mr. Davis, when United States Senator and when Secretary of War, had credit for brains and great shrewdness; but never did he need them so much as now, and as "necessity is the mother of invention," the fact of the need called forth from his fertile brain a plan of domestic diplomacy which would have done credit to Pitt in his palmiest days. However good a conception or plan may be, still it is of no use unless it can be put into execution, and just here was President Davis's greatest trouble. He had scores of officers about him ready to do his slightest bidding, but among them all he could think of no one exactly fitted for the kind of service he then had in view. When in his greatest distress of mind, walking the floor for hours at a time, thinking, thinking, thinking, it happened that Colonel Ralph Abercrombie, who was in command of a Louisiana regiment in General A. P. Hill's corps, came into Richmond, and, as was his custom, called immediately at the executive mansion. The Colonel had been known to Mr. and Mrs. Davis since a boy. Mr. Davis, when Secretary of War, had appointed him to a lieutenancy in the regular army. Both Mr. and Mrs. Davis were on the most intimate terms with his widowed mother, and though the Colonel was now about thirty years of age, they still called him Ralph. When, on this visit, he observed the President's anxiety, he naturally inquired the cause, and soon learned from Mr. Davis the outlines of his plan. The Colonel at once offered his services to put the President's plan into execution, only suggesting that, instead of opening the route to Washington via Chesapeake Bay and Leonardstown, Md., he would prefer a more northern route, for the reason that he was better acquainted with the Potomac between the Great Falls and Cumberland than with the route proposed by President Davis. When a lad, he had attended St. James' College, near Hagerstown, Md., and, by frequent drives through the country, had learned every foot of ground between that point and Washington city. Mr. Davis listened attentively, and when the Colonel had finished, he quickly replied that his offer of services had relieved his mind of a great anxiety; that he would accept them most gladly; and that he would agree to any route upon which the Colonel might fix. He told the Colonel, in addition, that he would appoint, to assist him, any one whom he might name, and that in opening and establishing the route he could employ whoever he pleased, and use any amount of funds that might seem necessary, as the project involved millions of money, if not the very life of the Confederacy; and that the few thousands it might cost would only be as dust in the balance, as compared with the advantages to be gained.