achieve a careful guidance of the yarn bundle into the slot plane the trough 7 usually also contains the same liquid which is filled into the main chamber 1 this being at a level which is indicated by reference numeral 14 such liquid is filled into trough 7 through an entrance 8 and carried off through exit 9 where an adjustable u tube 10 may be provided so as to define the level 14 the illustrated distance a between the guide walls 38 and 39 of plates 5 1 and 5 2 is not equivalent to the distance used in practice in practice a distance on the order of one millimeter or less is selected ordinarily this is determined by trial and can vary owing to the viscosity and temperature of the liquid and the thickness of the yarn bundle slots 11 and 12 are dimensioned so that only the liquid which adheres to the yarn bundle f passes from trough 7 to the main chamber 1 or from the main chamber 1 to the exterior of the apparatus for slot 12 this condition exists in cases where trough 7 is not provided with the same type of liquid as main chamber 1 fig2 shows that the two illustrated yarn bundles f are kept apart by the guide pin or bolt 3 these bundles extend over the whole width of slots 11 and 12 fig2 also shows that the deflection rods 13 15 1 and 15 2 are attached stationarily in the side walls 36 of the respective stretching bath halves 6 1 and 6 2 the operation of the apparatus has already been explained in u s pat no 5 046 225 and the previously mentioned european patent applications the two stretching bath halves 6 1 and 6 2.