Press your scroll wheel, the cursor changes to somewhat similar to a circle and four arrows. Slowly, move your mouse up/down/right/left to let it start autoscrolling. Try moving your mouse fast and away from that circle to increase rate or speed of scrolling. To change back, click rotate/scroll the scroll wheel again, the circle/round will disappear. You may even try here when typing your answer on ask-public (in Answer this question text field or text editing box or whatever)! (of course, the text should be lengtthy enough, you should see scroll bars)