The Signal of Liberty was begun in 1841 to serve as the mouthpiece of the Michigan abolitionist movement. It was edited for most of its history the Rev. Guy Beckley, a well-known abolitionist and proprietor of a stop on the underground railroad, and Theodore Foster, an experienced newspaper man and politician. The subscribers list for the Signal was a who's who of notable abolitionists in Michigan and across the midwest. It was published until 1848 when financial difficulties apparently led to its demise. The Michigan Liberty Press took up the cause and became the abolitionist paper of note.
For more on the history of the Signal of Liberty, read Carol Mull's piece on the newspaper.