used for a substitute for madder. By the action of bromine upon alizarine, Mr. Perkm 

 has recently obtained a derivative called bromalizarine, -which may also be used in 

 dyeing. For the manufacture of artificial alizarine, see ALIZARINE ; ANTHRACENE. 



Purpurine, the other red colouring matter of madder, with which the matiere 

 colorante rose of Gaultier de Claubry and Persoz, and the madder-purple of Runge, are 

 substantially identical, can hardly be distinguished by its appearance from alizarine, 

 which it also resembles in most of its properties. It crystallises in small orange- 

 coloured or red needles. When carefully heated it is almost entirely volatilised, 

 yielding a sublimate of shining orange-coloured scales and needles. It is slightly 

 soluble in boiling water, giving a pink solution. It is more soluble in alcohol than 

 in water, the solution having a deep yellow colour. It dissolves in concentrated 

 sulphuric acid, and is not decomposed on heating the solution, even to the boiling 

 point. It is decomposed by boiling nitric acid, and yields, like alizarine, phthalic 

 acid. It is distinguished from alizarine, by its solubility in alum-liquor. When 

 treated with a boiling solution of alum in water, it dissolves entirely, yielding a peculiar 

 opalescent solution, which appears of a bright pink colour by transmitted light, and 

 yellowish by reflected light. The solution deposits nothing on cooling, but on 

 adding to it an excess of muriatic or sulphuric acid, it becomes colourless, and the 

 purpurine falls down in yellow flocks. On this property depends the method of 

 separating it from alizarine. The compounds of purpurine with bases are mostly 

 purple. It dissolves in alkalis with a bright purplish-red or cherry-red colour. 

 If the solution in caustic potash or soda be exposed to the air, its colour changes 

 gradually to reddish-yellow, and the purpurine contained in it is decomposed, a 

 characteristic which also serves to distinguish purpurine from alizarine, the alkaline 

 solutions of which are not changed by the action of oxygen. The composition of 

 purpurino approaches very near to that of alizarine, but its chemical formula is 

 unknown. It communicatifi to calico, which has been printed with various mordants, 

 colours similar to those imparted by alizarine, but the red is more fiery, and the 

 black more intense than when alizarine is employed. On the other hand, the purple 

 dyed by means of purpurine has a disagreeable reddish tinge, and presents an 

 unpleasant contrast with the beautiful purple from alizarine. The name of this 

 colouring matter is therefore very inappropriate, and is calculated to mislead. The 

 colours dyed with purpurine are less stable than those dyed with alizarine, they 

 are less able to resist the action of soap and other agents than the latter. Hence, very 

 little purpurine is found in combination with the mordants, in such madder colours 

 as have undergone a course of treatment with alkalis and acids, after having been 

 dyed ; indeed, the principal object of this treatment appears to be the removal of this 

 and other substances, so as to leave compounds of alizarine only on the fabric. 

 Purpurine seems to abound more in the lower, stronger qualities of madder than in 

 the finer. To this cause, Eobiquet chiefly ascribed the superiority of the latter in 

 dyeing fast colours, and no better way of accounting for it has hitherto been suggested. 

 Purpurine forms the basis of the red pigment called madder-lake. 



Bubiacine is the name which has been applied to a yellow crystallised colouring 

 matter contained in madder. It coincides in most of its properties with the 

 madder -orange of Kunge. It crystallises in greenish-yellow lustrous scales and 

 needles. When heated it is entirely volatilised, yielding a crystalline sublimate. It 

 is only slightly soluble in boiling water, but more soluble in boiling alcohol, from 

 which it crystallises on cooling. It dissolves in concentrated sulphuric acid, and is 

 not decomposed on boiling the solution. It also dissolves in boiling nitric acid without 

 being decomposed. It dissolves in caustic alkalis with a purple colour. Its com- 

 pounds with earths and metallic Oxides are mostly red. When treated with a 

 boiling solution of pernitrate or perchloride of iron it dissolves entirely, yield ing a 

 brownish-red solution, which deposits nothing on cooling, but gives, on the addition 

 of an excess of muriatic acid, a yellow flocculent precipitate, consisting of a peculiar 

 acid, called rubiacic acid. 



Two amorphous resinous colouring matters, forming brownish-red compounds 

 with bases, have also been obtained from madder. Both are very little soluble in 

 boiling water. One of them is a dark brown, brittle, resin-like substance, very easily 

 soluble in alcohol, which melts at a temperature a little above 212 F. The other is 

 a reddish-brown powder, less soluble in alcohol than the preceding. These two 

 colouring matters, together with rubiacine, constitute probably the tawny or dim 

 colouring matter of the older chemists. They do not contribute to the intensity of the 

 colours dyed with madder, and exert a very prejudicial effect on the beauty of tho 

 dyes. If printed calico be dyed with a mixture of alizarine, and any one of these 

 three colouring matters, the colours are found to be both weaker and less beautiful 

 than when alizarine is employed alone. The red acquires an orange tinge, and tho 

 purple a reddish hue, whilst the black is less intense, and the parts of the calico 



