In German specifications it is required that the steelwork should first receive a coat of boiled linseed oil, in order that the red lead coating should be more coherent with the steel.
C. t has for its subject pavements and roads, their construction, mosaic floors; c. 2 is on white stucco for walls (opus albarium); c. 3 on concrete vaults, gypsum mouldings, stucco prepared for painting; c. 4 on building of hollow walls to keep out the damp, wall decoration by various processes; c. 5 on methods and styles of wall painting, the debased taste of his time; c. 6 on fine stucco made of pounded marble - three coats to receive wall paintings; c. 7 on colours used for mural decoration; c. 8 on red lead (minium) and mercury, and how to use the latter to extract the gold from wornout pieces of stuff or embroidery; c. 9 on the preparation of red lead and the method of encaustic painting with hot wax, finished by friction; cc. to-14 on artificial colours - black, blue, purple;, c. to white lead and ostrum, i.e.
The negatively electrified sulphur is seen to attach itself to the positively electrified parts of the plate, and the positively electrified red lead to the negatively electrified parts.
Most of these were simple records of patient and laborious analytical operations, and it is perhaps surprising that among all the substances he analysed he only detected two new elements - beryllium (1798) in beryl and chromium (1797) in a red lead ore from Siberia.
Litharge and red lead are used in silver and gold assays, acting as solvents for silica and any metallic oxides present.
Acids decompose it into lead dioxide and monoxide, and the latter may or may not dissolve to form a salt; red lead may, therefore, be regarded as lead orthoplumbate, Pb2Pb04.
The white and red lead are mixed together to form a putty, and are filled into the socket alternately with layers of well-caulked yarn, starting with yarn and finishing off with the lead mixture.
Lead sesquioxide, Pb203, is obtained as a reddish-yellow amorphous powder by carefully adding sodium hypochlorite to a cold potash solution of lead oxide, or by adding very dilute ammonia to a solution of red lead in acetic acid.
Commercial red lead is frequently contaminated with this oxide, which may, however, be removed by repeated digestion with lead acetate.