The narrative covers the eventful work of Congress for the past thirty years, and gives a much fuller inside view of Federal legislation during this period than can be obtained from Mr. BLAINE'S more pretentious work. No period in our national history is so full of interest as the times of which our author writes. The revolt from English rule and the establishment of our national government was one of the grandest epochs in history. In that period were determined the issue of national independence; in this epoch of even greater magnitude, the issue of national existence. Both periods alike witnessed the most terrible conflicts of armies, of bloodshed and suffering in both periods was shown the exercise of the highest and most brilliant statesmanship; and in both periods the Federal Legislature was witness to events scarcely less exciting and decisive than occurred on hundreds of bloody battle-fields. The exciting period of Secession, the departure of Senators and Representatives from Congress, the proclamation of war, the call for troops, the great uprising of the people of all sections, North and South, against each other, the act of Emancipation, the sanguinary battles of, and the close of the war, the return of peace, the assassination of President Lincoln, the election of Grant, the Electoral Commission and the seating of Hayes, the resumption of specie payments and a host of other equally impressive episodes and events, find in Mr. Cox an impartial historian. Of the importance of such a work, there is no need of saying anything, and it is quite enough to remark that the book taken all in all, is perhaps the most important, because of its impartiality and accuracy, that has so far been published during the present year. We have alluded to the fact that the author was a prominent actor in nearly all the legislation of this long period, and that he consequently possesses that personal and absolute knowledge which comes from actual participation. The following extract which is taken at random from page 117 of the volume discloses something of the author's happy faculty of seeing and describing things as they occurred to him. He says:-- "Being upon the Foreign Affairs Committee of the House of Representatives when the Trent affair occurred, the writer attended a dinner given by the Secretary at this then happy home. This was at a time when men held their breath in trepidation, lest Great Britain and the Powers of Europe might make the Trent matter the pretext to consummate their recognition of Southern independence. Some feared that a disparted Republic would have to give way before the jealous encroachments of those who sought to divide our country as they endeavored to imperialize Mexico.