The audible range of the Bells is dependent on geography and wind conditions. The east is mostly low lying, a factor which combines with the strength and regularity of the prevailing wind, blowing from west-south-west for nearly three-quarters of the year, to carry the sound further to the east, and more often. A 2012 study showed that in the 19th century, and under typical conditions, the sound of the bells would carry as far as Clapton, Bow and Stratford in the east but only as far as Southwark to the south and Holborn in the west. An earlier study suggested the sound would have carried even further.