The author, ח"ג ווידאווער, otherwise known as Henry Vidaver was a prominent 19th century American rabbi who frequently contributed news of America to the pages of Hamaggid.
Part of it reads:
"On Shabbat Chol Ha-moed Pesah, all were joyfully walking to the synagoguges, that day being especially joyous and a day of thanksgiving to God for the victorious end to the Civil War."
"However, how inscrutable are God's intentions! On the very day which we were saying "This is the day which the Lord hath made; we will rejoice and be glad in it," that day was turned to its dark opposite, a day of infamy for the entire United States. A voice was heard crying, "Abraham Lincoln, the President of the United States, fell at the hand of a murderer who accosted him in a theater. Friday evening the President and his dear family sat in the balcony to partake a little bit in the gladness of the people. From behind him, a man carrying a gun came and slew this righteous man."Solomon Schechter, reflecting in 1902 on his youthful reading, and the impression that Vidaver—only 14 years his senior—made on him:
"It was the dream of my childhood when I learned, through the Sepher Haberith and the letters of Hag Vidaver in the Hebrew weekly, Hamaggid, of the existence of a continent on which, according to my simple conceptions, people should stand on their heads, and yet somehow managed to walk erect and free and even move quicker and with a surer pace than we, with all our drill of thousands of years."In Seminary Addresses and Other Papers, 'The Emancipation of Jewish Science.'
Here's Rabbi Vidaver on Lincoln, in English (from the memorial on the Wednsday after the שבת חול המועד he mentioned in the Hamaggid article):