PORTER ON GRANT.The Sober Seeond Thought.E*traei» from mwr1* Jen*-tiAl from 1M2 10 1865.Tha following extracts from Admiral Porter’s diary* some of them written at the same ikaeaa his leuer to Welles in eofidemnaiion of Gen. Grant, show that he must have written that leUer.onder a curious pressure of dyspepaa and general irritation. The extracts appear iq the Washington Chronicle of fcov, 5?Cairo, III, Nov. 1SCA—It was after a hard day’s work at my desk, and going around among the vessels filling out. that I accepted an invitation to supper with Cspt- McAllister, Quarter Master U. 3. Army, who was living on board an old steamer.We were enjoying ourselves amazingly when a iiule bustle was heard, aud Gen-Grant was announced.This was an unexpected arrival, for the General was supposed to he in Co-riuih.I had never seen Gen. Grant before, and he was quite a different peraoo from what I expected. I had seen so many Generals daring tho war, with large staffs following them about, that I naturally looked around ior Gen- Grant’s staff. I could, howeTcr, see nothing but my own officers with iheir weil-Iaced coats-Captain McAllister came to my end of fhe cabin, with a plain-looking man, dressed in a citizen's brown cont, with a velvet collar, and a pair of gray pantaloons. All his habiliments were covered with dust, and looked as if they had traveled many a mile.Those clothes, seedy in the extreme, adorned the outer mao of Gen. Oiysses Grant.Duo always forms rather an exaggerated idea of a hero, and expects to see something beyond the ordinary run of men, if not in personal appearance, at least in the irapping3 of bis rank; hut General Grant was distinguished by neither of these, and stood before roe ou^ that occasion the plainest, moat unas-i Bunting man I ever beheld.Grant and Sherman had been two of my heroes ever Bince ihoy operated to* gather in Western Kentucky and Tonnes* see, although I had no acquaintance with either of them- I had closely scrutinized their operations since the breaking out of the war. I made up my mind that there was more good generalship in these two men than in any oLher two I had read of.In Grant 13aw the hold-on, bnll-dog courage tht will tell in the long mu against the best arranged, tactics, provided numbers and all are equal? and in Sherman I beheld the genius that led to .guoh achievements daring the rebellion.When iutcoduced, Grant took me quietly by the baud, na if I were an old acquaintance, with **How are you. Admiral?11McAlHater gave as a small table apart frum. the rest of Lhe company; We aat down to talk, with a wild duck and a bottle of champagne before us, neither of which Grant touched. While. 1 was looking earnestly al Grant, trying to make out how much of lhe man there wfifl under that nlam exterior, the Gen-