The following method of dyeing is perhaps the best one. Charge the dye-bath with the requisite dye-stuff and Glauber's salt, boil up, shut off the steam, enter the goods and let run for half an hour, without steam, then sample. If the shade of both cotton and wool is too light, add some more of the dye-stuffs used for both fibres, boil up once more, and boil for a quarter to half an hour. If the wool only is too light, or its shade different from that of the cotton, add some more of the dye-stuff used for shading the wool and bring them again to the boil. If, however, the cotton turns out too light or does not correspond in shade to the wool, add some more of the dye-stuffs used for dyeing the cotton, without, however, raising the temperature. Prolonged boiling is necessary only very rarely, and generally only if the goods to be dyed are difficult to penetrate or contain qualities of wool which only with difficulty take up the dye-stuff. In such cases, in making up the bath, dye-stuffs are to be selected some of which go only on the wool and others which go only on the cotton (those belonging to the second group). The goods can then be boiled for some time, and perfect penetration and level shades will result. If the wool takes up the dye-stuff easily (as is frequently the case with goods manufactured from shoddy) and are therefore dyed too dark a shade, then dye-stuffs have to be used which principally dye the cotton, and a too high temperature is to be avoided. In such cases it is advisable to diminish the affinity of the wool by the addition of one-fifth of the original quantity of Glauber's salt (about 3/8 oz. per gallon of water), and from three-quarters to four-fifths of the dye-stuff used for the first lot. Care has to be taken that not much of the dye-liquor is lost when taking out the dyed goods, otherwise the quantities of Glauber's salt and dye-stuff will have to be increased proportionately. Wooden (p. 173) vats such as are generally used for piece dyeing have proved the most suitable, they are heated with direct or still better with indirect steam. The method which has proved most advantageous is to let the steam run into a space separated from the vat by a perforated wall into which space the required dye-stuffs and salt are placed. The mode of working is influenced by the character of the goods, and the following notes will be found useful by the union dyer.