DIAMINE COLOURS 
 
 COUPLED WITH NITRAZOL C 
 ON COTTON YARN 
 
 CASSELLA COLOR COMPANY 
 
 182 and 184 Front Street, 
 
 NEW YORK. 
 
 Boston: 39 Oliver Street. 
 
 Philadelphia: 126 and 128 South Front Street. 
 Providence: 64 Exchange Place. 
 
 Atlanta: 47 North Pryor Street. 
 
 Montreal, Canada, 59, William Street. 
 
 No. 3447 
 
On account of the liability of Nltrazol C, pat., to spontaneous 
 combustion, we do not carry this article in stock. Wherever the 
 use of same is mentioned in this hand-book, we recommend, in- 
 stead, the use of diazotized Paranitraniline, for the coupling of 
 our colors. The final result is exactly the same. 
 
 CASSKblyA COIyOR COMPANY. 
 
 DIAMINE COLOURS COUPLED WITH NITRAZOL C 
 
 ON COTTON YARN. 
 
 The cotton is dyed in the manner customary for Diamine Colours, 
 for about one hour in a boiling bath, with the addition of y 2 — 1% soda 
 ash and 10 — 20% desiccated Glauber’s salt. 
 
 The stated quantities of dyestuff are those actually absorbed in the 
 standing bath, and the starting bath has to be charged with a larger 
 quantity of dyestuff, depending on the volume of the liquor. 
 
 Of Glauber’s salt and soda, about one-quarter to one-fifth the quan- 
 tities used for the starting bath are required for dyeing of the subsequent lots 
 
 The coupling is effected by treating the dyed and rinsed cotton in 
 one of the coupling baths prepared with Nitrazol C or Paranitraniline C 
 as described below. 
 
 The cold coupling bath is charged successively with the solutions 
 of Nitrazol or diazotised Paranitraniline, soda and acetate of soda; in this 
 bath the cotton is treated for y 2 hour and then rinsed. 
 
 When coupling in dyeing machines, it is well to omit the soda and 
 acetate of soda, and to increase the quantity of Nitrazol or Paranitraniline by 
 one-fourth to one-third. It is an advantage, when coupling in machines, 
 particularly in packing apparatus, to prolong the duration of the coupling 
 process, adding the Nitrazol in two to three lots, if possible whilst working 
 the pump from the inside towards the outside. 
 
 For shading the dyeings, small quantities of Basic Colours may be 
 added to the coupling bath, e. g. for Black 0.2 — 0.3% Methylene Blue BB. 
 
 a) Coupling with Nitrazol C. 
 For 100 lbs cotton. 
 
 For 1% — 2% dyeings with 
 
 For 3 — 4% dyeings with 
 
 2 lbs Nitrazol C 
 
 3 — 4 lbs Nitrazol C 
 
 y 2 lb. soda ash 
 
 % — 1 lb soda ash 
 
 3 oz acetate of soda 
 
 3 — 4 oz acetate of soda. 
 
 To dissolve the Nitrazol C, it should be stirred up with a little cold 
 water (20° C. or 68 — 77° F). Any lumps that may have formed should be 
 carefully broken up, the Nitrazol being finally brought into solution by 
 pouring a sufficient quantity of cold water over it.