PAINTS AND WHITEWASHES 227 



zinc oxide. Whether it is a mixture or a compound is not 

 determined. 



Zinc Oxide or Chinese White. This material works well 

 in oil, requiring a very large amount, approximately 20 per 

 cent of its weight, and is used as a house paint and as 

 an enamel for inside surfaces as bathtubs, plumbing, etc. 

 It is the whitest of all the paint pigments. It will not 

 collect dust as much as does white lead. When mixed with 

 white lead it retards or entirely prevents the discoloration 

 of the latter by hydrogen sulphide. 



Lithopone. This-is a mixture of zinc sulphide and barium 

 sulphate, heaied, suddenly chilled and then ground. This 

 material has a brilliant color, and more body than has white 

 zinc. It is permanent, is fine in texture and mixes well 

 with oil and other pigments, except those containing lead or 

 copper. It is used advantageously as a marine paint. It is 

 largely used in the oilcloth industry. 



Barytes. Barium sulphate is very heavy, and may be 

 mixed with all pigments, but it has little body, dries slowly, 

 and does not mix well with oil. When used as an adulterant 

 of white lead its use is to be avoided. When applied in 

 limited amount as an extender in mixed paint, it imparts 

 desirable qualities. It is used by the United States Navy 

 as a basis for battle-ship gray. 



169. Green Pigments. Brunswick green is oxychloride 

 of copper. This pigment works well with oil, has a fair 

 covering power, but is rather pale in color. Other pigments 

 sold under this name consist of a mixture of Prussian blue, 

 chrome yellow, and barytes in varying proportions. They 

 work well in oil, have good covering power, and last fairly 

 well, but they cannot be used with alkaline substances, com- 

 pounds of sulphur, or in the presence of hydrogen sulphide. 



Chrome greens are mixtures of chrome yellow and Prussian 

 blue. They are yellowish green in color, mix well with oil 

 and with other colors, have good covering power, and are 

 permanent. 



