papermaking machine wire 5 the slot comprises an inlet 2 and an outlet 3 connected by a central portion 4 both the inlet and the outlet taper towards the portion 4 which is rectangular in transverse cross section i e at right angles to the direction of stock flow the portion 4 includes two oppositely directed right angled portions 6 and 7 a pipe 9 extends through the body 15 and communicates with the central portion 4 of the passage between the angled portions 6 and 7 the pipe 9 has an injection nozzle 8 where it communicates with the portion 4 the stock containing chest contains holey rolls 11 for evening stock flow and is connected by piping 16 to a flow distributor 12 the outlet 3 of the slice 1 is disposed above the breast roll 17 of the papermaking machine suction boxes 18 are disposed beneath the wire 5 and are connected by piping 19 to an air separator 13 from which piping 20 only a part of which is shown leads back to the headbox 10 the flow direction in the piping 19 and 20 is denoted by arrows in use of the apparatus a dispersed fibre stock is pumped from the flow distributor 12 to the chamber 14 of the headbox the holey rolls serving to even the flow from the chamber the stock passes through the inlet 2 into the passage 4 and through the angled portion 6 the taper of the inlet 2 and the changes of direction in the angled portions 6 and 7 impart high intensity small scale turbulence to the flow a gas normally air is passed through the pipe 9 and is discharged into the stock through the.