the digestion at 20 u00b0 sr a breaking length of 8 4 km and a tear index of 6 9 mn u00b7 m2 g are measured for the birch for example 5 a yield of 83 99 and a whiteness of 69 82 iso were determined after the digestion a sodium sulphite digestion solution with addition of 0 1 of anthraquinone are added at a liquor ratio of wood digestion solution 1 3 to beech chips after steaming 90 minutes with saturated steam at 105 u00b0 c the total amount of chemicals used was 16 5 calculated as sodium sulphite based on oven dry beech chips the beech chips impregnated with the solution of chemicals were heated to 170 u00b0 c examples 6 7 or to 160 u00b0 c example 8 and digested over 60 minutes example 6 or 48 minutes example 7 and over 55 minutes example 8 the consumption of sulphite was 54 3 of the originally used sulphite in the case of example 6 a consumption of 48 5 was determined in the case of example 7 and the consumption of sulphite was 35 4 based on the originally used sulphite in the case of example 8 the yield was determined as 74 1 for example 6 a yield of 75.