When the Second Indiana, under Col. Bowles, fled from the field after the first Mexican onset upon the American left, leaving the way to Taylor’s rear open, some one suggested--says Niles--a retreat. “Retreat!” exclaimed Taylor; “No; I will charge them with the bayonet.” Niles reported many human incidents of the war, and dwelt upon the barbarity of the Mexicans: They generally killed and plundered, even of their clothes, all whom the current of battle threw into their hands. We, on the contrary, saved the lives of all who threw down their arms, and relieved the wants of the wounded, even in the midst of battle. I have seen the young American volunteer, when bullets were flying around him, kneel beside a wounded Mexican and let him drink out of his canteen. In one heap of wounded Mexicans we came upon a groaning man, whom an Illinois soldier raised and gave water. We had gone only a few steps past when the soldier thus helped twisted himself upon his elbow and shot our man through the back dead; three or four volleys instantly repaid this treachery. The first intimation of the revolution in news-gathering which occurred in the middle forties was furnished _Evening Post_ readers in the issue of May 27, 1844, when the Washington correspondent told of Morse’s successful experiment with the telegraph two days earlier. “What is the news in Washington?” was the question asked from Baltimore, where the Democratic National Convention was about to meet. “Van Buren stock is rising,” came the answer. On May 31 the correspondent sent another brief mention of MORSE’S TELEGRAPH.--This wonderful invention or discovery of a new means of transmitting intelligence, is in full and perfectly successful operation. Mr. Morse is the magician at the end of the line, and an assistant who does not spell with perfect correctness officiates. There have arrived numerous telegraphic dispatches since the meeting of the Convention at Baltimore at nine o’clock this morning. By one we are informed of the nomination of Mr. George M. Dallas, of Philadelphia, for Vice-President. All the New York newspapers, the _Herald_ leading, shortly had a column of telegraphic news, and from that in the _Evening Post_ we can trace the steady extension of the wires. In the early spring of 1846 communication was opened between New York and Philadelphia. When war was declared, April 24, the line to Washington was incomplete, not having been finished between Baltimore and Philadelphia, but the gap was soon closed. The fastest carriage of news between the capital and New York, 220 miles, had been that of Harrison’s inaugural message, weighty with its Roman consuls and Greek generals, in eleven hours; now eleven minutes sufficed. By the middle of September, when the line to Buffalo was complete, the country had 1,200 miles of telegraph, reaching above Boston towards Portland, to Washington on the south, and to Harrisburg on the west.