M. TECHNOLOGY. 511 



for the richness of the milk. Should the liquid be strongly 

 colored, we shall have every intensity of shade from entire 

 want of color to the opposite. With this instrument, there- 

 fore, assuming any given solution as a standard, and noting 

 the 'last degree which can be read through it, it is easy to de- 

 termine whether any second fluid has a greater or less per- 

 centage of coloring matter. 18 (7, xli., October 11,1871,647. 



INDULIX BLUE. 



It is reported that Indulin blue has, by improved methods 

 of preparation, become tolerably cheap, and may be recom- 

 mended as a genuine color. It is first to be dissolved by rub- 

 bing up in some water, and then boiling in from 50 to 100 

 pints of water. For use, the bath is to be rendered alkaline 

 with borax or soda ; the coloring matter and the wool must 

 be heated to 212 Fahrenheit; and the boiling must be con- 

 tinued until a sample, taken out and boiled in water acidu- 

 lated in sulphuric acid, exhibits the desired shade. The en- 

 tire mass of wool is then to be taken from the alkaline bath, 

 and drained off, washed, and treated in a boiling-water bath 

 with sulphuric acid and chloride of tin, in which the blue col- 

 or, as shown in the sample, will become quickly developed. 

 After some further boiling the operation will be completed. 

 23 (7, November 15, 1871, 318. 



IXDIGOLINE. 



Indigoline is a new dye-stuff, soluble in boiling water, which 

 is used to produce shades of indigo blue, although it is not 

 likely to displace the indigo bath when solidity of coloring 

 is required. Alum is to be used with it, as a mordant, upon 

 wool, with a little cream of tartar and sulphuric acid, or sul- 

 phate of soda and sulphuric acid. If the blue produced by 

 this dye is passed through a bath of ordinary soluble violet 

 it will take a beautiful violet tinge. For dark green, Russian 

 green, etc., indigoline is well adapted as a coloring for the 

 background. 25 C, 1872, ix., 72. 



NOX-POISONOUS GREEN COLOR. 



A new green has been discovered which is said to be bril- 

 liant enough to replace the poisonous shades produced by 

 arsenic. It is composed of twenty parts of oxide of zinc and 



