452 On Madder, and [Dec. 



those of Etna, possessing augite, and labradorite. Whether 

 these are all true species, future researches must determine. 



Article VI. 



On Madder, and Madder Dyeing.* 



Species of Madder . — The species of madder mentioned in 

 this paper are : 1. Spires' madder, sold at 28 rixdollars the 

 hundred-weight (centner) ; 2. Munjeet, at 28 rixdollars ; 

 3. Avignon madder, 27J rixdollars ; 4. Secondary quality, 

 from the same place, 20 rixdollars ; 5. Alsace madder, 25 

 rixdollars; 6. Dutch madder, 25 rixdollars ; 7. Alizari, or 

 Levant madder-root, 22 rixdollars; 8. Autumn-red (^erJs^- 

 rothe) 18 rixdollars; 9. Red bud {Keimrothe) 12 rixdollars. 

 All these varieties absorb different quantities of moisture 

 when exposed to the air ; so that it is necessary to dry them 

 at the temperature of 212° F. before weighing them. 



Cotton Mordants. — For testing and examining Aiadder 

 chemically, the aluminous cotton mordant {Thonhexz-kattun) 

 is of great importance. The process consists in impregnat- 

 ing the cloth with acetate of alumina ; by immersing it in 

 a solution consisting of 30 parts of alum, 30 parts acetate of 

 lead, and 80 parts of water, pressing it between cylinders, 

 and drying it rapidly. It is then allowed to hang up for 

 eight days, washed in a stream of water, afterwards boiled, 

 and lastly, for the purpose of experiment, passed through 

 distilled w^ater. 



The iron mordant for cotton, mentioned in this paper, is 

 formed by impregnating the cloth with a solution of iron 

 and alum (1 in 120 water) and washing it. A black mor- 

 dant enables the qualities of the colouring matter to be 

 more readily distinguished. This mode of proceeding is 

 analogous to the re-action, ascertained by testing dilute 

 solutions. 



• Tins paper constitutes an excellent sequel to those which were published in 

 the first volume of this Journal ; as its object is to present a more minute descrip- 

 tion of the formation of several of the colours attached to these papers. It is taken 

 {rova. Erdmann und Schweigger SeideVs Journal, far Praklische Ckemie, v. 362; 

 into which periodical it has been extracted, from the " Chernische technische 

 Monographic des Krapps oder vergleichende untersuchunguti der Krappfarbestoff 

 und der verschiedenen Krappsorten : Alizari, Krapp, Munjeet und Rothe in ihrem 

 verhalten xur geheizlen Baumicollenfasser , von Dr. F. Y. Runge." 



