Abstract: An apparatus for continuously applying a liquid to a web has a nozzle having an elongated opening and directed at the web, a strip slidable steplessly along the opening of the nozzle to vary the length thereof, and a foraminous transfer screen displaceable transversely between the web and the nozzle opening and having a back face turned toward the nozzle and a front face turned toward the web. Back and front troughs engage the respective faces of the screen and define therewith back and front chambers while respective back and front steplessly displaceable pistons in each of the troughs engage the respective screen faces and each define an end wall for the respective chamber. The chambers are filled with a treatment liquid so that the liquid will wet the respective face of the screen over an area determined by the position of the pistons and a gas is supplied to the nozzle to blow the gas through the nozzle opening and through the screen and thereby transfer liquid carried by the screen to the web.