PAINTS, DYES, AND VARNISHES 



and coloring, and has lost its former popularity since 

 the discovery of so many other brilliant greens. 



One of these brilliant greens is the compound of the 

 oxides of zinc and cobalt, known as cobalt green. For 

 commercial painting this pigment is too expensive, but as 

 an artists' color it is very popular. It is permanent, not 

 affected by mixing with other pigments, and has good 

 covering power. On account of these qualities, numer- 

 ous efforts have been made to find a cheap way of 

 manufacturing it commercially, but so far these have 

 been unsuccessful. 



Besides these mineral greens there are others, such as 

 zinc green, titanium green, manganese green, and 

 Brighton green, that have been employed more or less 

 extensively at different times, but are of relatively 

 little importance at present. Zinc greens are made by 

 mixing zinc chrome, Prussian blue, and barytes. Ti- 

 tanium green is a ferrocyanide of titanium which was 

 made originally as a substitute for the arsenical greens, 

 but is too expensive for practical purposes. Manganese 

 green is essentially a manganate of barium, and is used 

 very little as a pigment. Brighton green is a preparation 

 of the basic acetate of lead. 



BLUE PIGMENTS FROM THE MINERAL WORLD 



Although the various shades and tints of blue are 

 among the most important as colors, the number of blue 

 mineral pigments is relatively small. Fortunately 

 this deficiency in number is more than counterbalanced 

 by the permanency of these pigments. The three most 



[295] 



