Gen. W.T. Sherman was a passenger on the steamer Rob Roy, this morning. He was on his way to Hamilton, Ill., where he will rusticate until after the 4th. He was accompanied by his son, (who has just left Yale college), Dr. Alexander, Col. Bacon and Major Hartz. While the boat was lying at the wharf a large number of our citizens embraced the opportunity to go aboard and give the General a hearty shake of the hand.