Henry C. Calhoun is the son of Granville Calhoun, who speaks in the previous poem.
Granville had been the County Judge for many years, and wanted to be elected one more time so that he could "round out a service / Of thirty years." His friends, however, betrayed him, and "a new man" was elected. Granville was "seized" with "a spirit of revenge," with which he infected his four sons.
Henry revenged his father's disappointment by rising to "the highest place in Spoon River." It is not clear from the poem exactly what this position is; the poem only says that Henry sought "wealth and...power" with a "furious energy."
Although the poem does not specify, it seems that Henry's rise to power did not bring happiness with it. He describes revenge as "an envenomed [poisoned] robe," and advises us to avoid it.
In giving his advice, Henry uses allusions to classic Greek mythology. He says that his father sent him along "the path that leads to the grove of the Furies." The Furies were three goddesses who punished mortals for their crimes.
He also refers to the Fates, three goddesses who controlled human destiny. He says that if you see them weaving, and you see the "thread of revenge," you should cut it away, "lest your sons, / And the children of them and their children / Wear the envenomed robe."
Henry expresses bitterness in this poem, directed at his father, Granville. Henry is haunted by the "face of [his] father" (3), and he mentions the "admonitions" or warnings from his father to "punish Spoon River / To avenge the wrong the people did" to Granville (7-9). In following Granville's advice, Henry did become wealthy and powerful, but at what cost? He blames his father for sending him down the "path that leads to the grove of the Furies" (13), which is an allusion to the avenging spirits of Greek mythology. Here, he advises others to cut that "thread of revenge" (18), so the readers' sons and children do not bear the necessity to seek revenge like Henry felt from his own father. This poem is a cautionary tale--do not poison your children with your own hate and spite, even if you do not achieve your goals, because it could ruin their lives just as equally or more than it ruined yours.