Abstract: During the successive discharge and conveyance, along a conveying path, of items of mail from a stack by a continuously driven conveying device and an externally controllable removal member arranged to transport successive items from the stack to the region of action of the conveying device, the desired spacing between each pair of successive items is established automatically as a function of the length of that item of such pair which is the leading item on the conveying path such that for a leading item whose length exceeds a predetermined length value, the next succeeding item is transported from the stack when the distance between the trailing edge of that leading item and the leading edge of the next succeeding item reaches a given first spacing value, and for a leading item whose length is less than the predetermined length value, the next succeeding item is transported from the stack when the distance between the leading edge of that leading item and the leading edge of the next succeeding item reaches