L. TECHNOLOGY. 435 



trate of protoxide of mercury added. The solution of this 

 compound in an alkali is filtered, and precipitated by means 

 of an acid. The precipitate contains variable quantities of 

 alizarine and purpurine. 14 (7, CXCLX., 1871, 332. 



LACTARIX. 



Lactarin is a substance which has been lately introduced 

 as a substitute for albumen for manufacturing purposes, and 

 it is said to have great advantages on the score of cheapness 

 and convenience of preparation. It is essentially a form of 

 caseine, rendered impure by a little fat and the salts of milk. 

 For use, it is diluted with water, dissolved in ammonia, and 

 then added to the coloring matter. 25 C, xxyii., July 16, 220. 



PHENYL BROWN. 



The new coloring matter, phenyl brown, seems to be an im- 

 portant addition to the resources of the dyer, since shades of 

 great beauty and considerable variety can be obtained, espe- 

 cially those adapted to dyeing wool, and requiring no mor- 

 dant. The colors also are genuine, and capable of gradation 

 between pomegranate brown and roe brown, in all shades of 

 the so-called Havana. The method of preparing this brown 

 consists in adding to one part by weight of phenol, ten or 

 twelve parts of the so-called nitro-sulphuric acid (a mixture 

 of English sulphuric acid and nitric acid), introduced in small 

 portions, and allowed to stand after each addition until the 

 reaction has ceased. Heating of the mixture is to be care- 

 fully avoided, and the addition of the acid is to be stopped as 

 soon as the red nitrous acid vapors have ceased to exhibit 

 themselves. The product of this reaction is to be put into a 

 considerable quantity of water, by which a brownish deposit 

 is thrown down, which, when collected, washed, and dried, 

 forms the phenyl brown. The washing is difficult if the re- 

 moval of all the acid is to be accomplished, which, however, 

 is not necessary for the objects of the dyer. This brown is 

 but little soluble in cold water, and still less so in hot, but is 

 quite soluble in ether, alcohol, or acetic acid, and still more so 

 in a mixture of acetic and tartaric acid. It is also easily dis- 

 solved in the solutions of caustic alkalies and their carbonates. 

 When heated, it melts to a black resinous mass. 15 C, 1870, 

 86. 



