a unit for the transfer and distribution of a liquid using capillary action has an elongated shaft and a screen . the shaft includes a first capillary medium suitable for drawing the liquid from a reservoir into the shaft when a bottom portion of the shaft is disposed in the liquid . the screen is connected to the shaft and includes a second capillary medium suitable for receiving the liquid drawn by the first capillary medium and distributing it over at least a major part of the screen where it evaporates .