For an air-jet loom, a blast of air would seem to be an effective way of inserting the filling, but to get enough traction on the filling yarn it is necessary to use very high air velocities. When an air jet is allowed to expand freely, the moving air is contained within an imaginary cone whose axis is coincident with that of the air jet. The air just emerging from the nozzle is highly energetic and, as it moves away from the nozzle, it entrains some of the surrounding air which tends to slow the mass down. Thus, as the