In Philadelphia, Mississippi, three civil rights workers disappear while trying to help blacks register to vote. Michael Schwerner, Andrew Goodman and James Chaney are ambushed and killed by Ku Klux Klansmen. Six weeks later, their bodies are found buried in an earthen dam.

1788,The Constitution of the United States takes effect, as New Hampshire becomes the ninth state to ratify the document.

1834,Cyrus Hall McCormick receives a patent for his reaping machine, the grain-cutting invention that revolutionizes farming.

1982, A jury in Washington, DC, finds John Hinckley, Junior not guilty by reason of  insanity for shooting President Ronald Reagan and three others. Hinckley, who said he shot Reagan to impress actress Jodie Foster, is committed to a psychiatric hospital. And finally, also that same yearIt's cool on me, in the army services will be the best thing in my career, because you know what they recongnize that hard work the air forces doing.

Prince William, second in line to the British throne, son of Prince Charles and the late Princess Diana, is born in London.

Today in History, June 21th, Camille Bohannon, the Associated Press.