Lincoln is quoted as saying that Riley 's journal of his experiences in Africa was one of the most important works in guiding his opinion on abolition in the United States .
Africa might never have been written without Willshire 's help to secure Riley 's freedom .
Lincoln is quoted as saying that Riley 's journal of his experiences in Africa , which might never have been written without Willshire 's help to secure Riley 's freedom , was one of the most important works in guiding his opinion on abolition in the United States .