On the evening of May 4, two to three thousand workers gathered in Chicago’s Haymarket Square to protest the killing of two strikers by police at the McCormick Reaper plant the day before. Despite their anger, they didn’t become violent but listened peacefully to three speakers who urged them to continue their fight for socialism and an eight-hour day. Pacing through the crowd was Chicago’s mayor, Carter Harrison, who decided the meeting was no cause for worry and went home to bed. So, too, when it began to rain, did all of the women and children and most of the men, until all that remained was a cluster of two to three hundred. The last speaker, Samuel Fielden, a former Methodist minister, was just concluding his remarks.

But a few blocks away at the Desplaines Street police station, two detectives rushed in to report to Inspector John “Black Jack” Bonfield that Fielden was using “inflammatory language.” Bonfield was not a man given to lengthy deliberation, nor could he have been described as sympathetic to the labor movement. That very evening, according to one witness, he had confided that “the greatest trouble the police had in dealing with the Socialists was that they had their women and children with them at the meetings so that the police could not get at them. [Bonfield] said he wished he could get a crowd of about three thousand of them together, without their women and children, and he would make work of them.” Upon hearing his detectives’ report, the inspector seemed to have thought his opportunity had arrived. In the next moment he was racing his squad of policemen down to the square at a run. Arriving at the wagon on which Fielden stood, he shouted, “I command you, in the name of the people of the state of Illinois, immediately and peaceably to disperse!” Fielden protested that they were peaceable, but then relented and agreed to leave.

That was the moment someone—it was never learned who—chose to throw a bomb. It landed among the policemen, and the ensuing explosion rocked the street. After a stunned silence, the policemen grabbed their guns and fired recklessly into the crowd—and into each other. According to the Chicago Tribune, a police official acknowledged that “a very large number of police were wounded by each other’s revolvers.” There was no evidence that the workers ever fired back. When the Haymarket Riot ended, seven policemen were fatally wounded. No count was taken of civilian casualties, but according to the Chicago Herald, some fifty lay dead or wounded in the streets.

That was just the beginning of the Haymarket affair. Within the next few weeks, the police indiscriminately arrested anyone known as a radical. Thirty-one people were indicted, and eight were brought to trial. None of the eight were found guilty of throwing the bomb, but they were convicted by a hysterical public, an allegedly packed jury, and a clearly biased judge on circumstantial evidence of being “accessories before the fact” and “accessories to each other” in the murder of the single policeman who was indisputably killed by the bomb.

All three speakers at the meeting were convicted, and on November 11, 1887, four men, including two of the speakers, were hanged. One of the eight committed suicide in his cell, and the remaining three, including Fielden, were pardoned in 1893 by Gov. John Peter Altgeld, who held that Bonfield’s unnecessary action made him “responsible for the death of the police officers.” Altgeld himself was the final casualty of the Haymarket affair: his beliefs cost him his next election.

Emily Dickinson died on May 15 of a kidney ailment. She was fifty-five years old, and her reputation didn’t extend much farther than the town line of Amherst, Massachusetts, where she was known as an eccentric, spinster recluse who wore only white. For the preceding sixteen years she had confined herself to the home and garden she shared with her younger sister Lavinia and had avoided contact with all but her closest friends. She had sent samples of her verse to a few well-known men of letters, but they had uniformly discouraged her, saying that what she produced didn’t merit the term poetry. Dickinson had accepted their judgments and her obscurity. Upon her death, only a handful of her poems had been published.

After Dickinson’s funeral, her sister Lavinia began sorting through her belongings. In accordance with Dickinson’s instructions and contemporary tradition, Lavinia consigned her sister’s correspondence to the flames. Then, one day, while digging through a bureau, Lavinia discovered a box she’d never seen before. Within it she found sixty small booklets of her sister’s poems, made by folding sheaves of writing paper in half and sewing them together up the spine. Lavinia was astonished. She knew her sister wrote poetry, but she had no inkling she had written so much or preserved it so carefully. Over time, other booklets turned up in various hiding places, and envelopes, too, stuffed with poems scrawled on slips of paper.

Lavinia became determined to see her sister’s poetry published. She pestered the writer Mabel Loomis Todd until Todd accepted the task of literary executor. Fifty-nine years after Emily Dickinson’s death, nearly all of her poems had been published. Today Amherst’s recluse ranks among America’s greatest poets.

• April 22: In the first presidential address on labor, President Grover Cleveland proposes that a national labor commission be created to arbitrate strikes.

• May 4: The first truly practical phonograph, called the Graphophone, is patented by Chichester Bell and Charles Sumner Tainter.