The online Emily Dickinson Archive, to be inaugurated on Wednesday, promises to change all that by bringing together on a single open-access Web site thousands of manuscripts held by Harvard University, Amherst College, the Boston Public Library and five other institutions. Now, scholars and lay readers alike will be able to browse easily through handwritten versions of favorite poems, puzzle over lines that snake along the edges of used envelopes and other scraps of paper, or zoom in on one of Dickinson’s famous dashes until it almost fills the screen. .."