392 VEGETABLE SUBSTANCES. 



reported to be more easy to work, to require the ad- 

 dition of less solvent material, to give less trouble in 

 the dyeing vessel, and to furnish a purer colour. 

 Guiliche recommends that the application of heat 

 should be avoided in the preparation of arnatto. 

 There can indeed be no question that this substance 

 is very much injured in its preparation ; as all vege- 

 table extracts, when exposed to the direct action of 

 fire, have their properties lessened, or even altered, 

 by partial charring ; an accident which never fails to 

 occur in a greater or less degree. In the country of 

 its production, we are told that this colouring matter 

 is much superior when used, as by the aborigines, 

 fresh from the trees. The Brazilians, by another 

 method of preparation, produce a permanent crimson 

 colour from arnatto. The Spanish Americans mix 

 the berries after having undergone a particular pro- 

 cess with their chocolate, to which, in their opinion, 

 it not only gives an excellent tint, but imparts valua- 

 ble medicinal virtues. 



The arnatto of commerce is moderately hard, of a 

 brown colour on the outside, and a dull red within. It 

 is seldom employed in England but as a dye for silken 

 stuffs, or as an auxiliary in giving a deeper shade 

 to the simple yellows. Its colour is a bright orange, 

 but this is extremely fugitive, fading very fast on 

 exposure to the air. It however powerfully resists 

 soap and the action of the strongest acids. Dr. Ban- 

 croft, in making experiments on this substance, found 

 that pieces of linen and cotton dyed in the usual way 

 with arnatto, and subjected to the action of chlorine, 

 not only retained their colour, but, on the contrary, 

 bore exposure to the atmosphere longer than these 

 pieces similarly dyed which had riot been so treated. 

 Arnatto is acted upon with great difficulty by water, 

 to which it imparts only a pale brown tinge. When 

 made into a dye-bath, alkali is therefore always 



