*** mouse-drag.el lets you do scrolling by dragging Mouse-2
on the buffer.

You click the mouse and move; that distance either translates into the velocity to scroll (with mouse-drag-throw) or the distance to scroll (with mouse-drag-drag). Horizontal scrolling is enabled when needed.

Enable mouse-drag with: (global-set-key [down-mouse-2] 'mouse-drag-throw) -or- (global-set-key [down-mouse-2] 'mouse-drag-drag)