Book Description

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1902 edition. Excerpt: ...T. M. LEGGE. CHAPTER XXIX THE LESIONS RESULTING FROM THE MANUFACTURE AND USES OF POTASSIUM AND SODIUM BICHROMATE Peculiar lesions--erosion of the septum of the nose and the production of ulcers on the skin--are caused by bichromate of potassium or sodium. Erosion of the septum is found only among persons engaged in the manufacture of the salts, but ulceration of the skin of exposed parts, principally the hands, although most severe and most frequently met with among the same class of operatives, may be detected among persons engaged in the many industries in which the salts are used in solution. Bichromate of potassium and sodium, commercially known as "bichromes," are used largely--1. In the manufacture of colours, such as the various chrome yellows, by the interaction of lead acetate and bichromate of potassium. 2. In dyeing and calico-printing. In dying cotton yarn the material is soaked in lime water, and, after wringing, is transferred to a vat containing lead acetate. It then passes through a solution of bichromate which develops the yellow colour on the fibre. In calico printing potassium bichromate is used in the indigo blue discharge style, when it may be printed from a paste containing 40 per cent, of bichromate, which will discharge the colour from the blue material after suitable treatment. Or it may be used for the production of chrome lead colours by first printing the desired pattern on the calico with a paste containing acetate of lead, and subsequently passing this through a 2 to 5 per cent, solution of bichromate. Potassium bichromate is the most important mordant for wool. The mordanting bath is prepared with 2 to 4 per cent, potassium bichromate (of the weight of the wool) and the necessary quantity of water, ...