1862.] on Mauve and Magenta. 481 



obtainable in succession from 100 lbs. of coal ; remark how they 

 gradually diminish in size, and how small, I might almost say insig- 

 nificant, appears tlie bulk of Magenta finally obtained. But compare 

 tlie bulk of wool which this minute quantity will dye. It approximates 

 to the bulk of coal with which we started. This comparison evinces 

 perhaps suflRciently the extraordinary tinctorial power which this class 

 of (lyes possesses ; but a very simple experiment may possibly convey to 

 you this idea even in a more impressive manner. The white paper 

 which covers this large frame has been dusted over with a minute 

 quantity of Mauve; a second one is treated in a similar manner with 

 Magenta. The quantity of colouring matter is so small, that the paper 

 has retained its original white colour, but observe how it changes, 

 when I dash a beaker full of spirit against these squares ; immediately 

 the lovely purple of Mauve is developed upon one of them, whilst 

 the other one exhibits the dazzling crimson of Magenta. 



But let us now proceed to illustrate the mode of dyeing. For 

 this purpose I introduce silk and wool, both unspun and wovefi, in 

 succession, into solutions of Mauve, of Magenta, and lastly, of a 

 splendid new Purple, lately discovered by Mr. Nicholson. Observe 

 the extraordinary facility with which the coal-tar-colours are fixed 

 both on wool and silk. These materials require no previous prepara- 

 tion, being dyed, in fact, simply by dipping, without the aid of any 

 mordant. Silk and wool are animal substances; vegetal materials, such 

 as cotton and linen, unless previously submitted to a special treat- 

 ment, are scarcely affected by these dyes. This fact admits of being 

 beautifully illustrated by dyeing linen fabrics on which ornaments 

 have been embroidered in silk ribbon. The articles, when coming out 

 of the bath, appear uniformly dyed ; but by washing, first in pure 

 water and then in dilute ammonia, the colour rapidly vanishes from 

 the linen ground, leaving the silk embroidery in brilliant colours. 

 This extraordinary predilection of the aniline-colours for animal sub- 

 stances is, moreover, strikingly illustrated by the condition of my 

 hands, which by this time have acquired a thoroughly Magentic 

 appearance. Fortunately, the coal-tar-colours are unable to resist the 

 action of chloride of lime, and I have therefore only to immerse my 

 hands for a moment into a solution of bleaching powder. 



Already the colour on my hand, you observe, has gone, but with 

 the colour, I am afraid, my time too. Let me endeavour to bring 

 this lecture to a conclusion. I have fulfilled in a measure the promise 

 which 1 gave you at the commencement of this discourse. We have 

 crossed together the extensive field which stretches between coal and 

 colour. I am impressed, deeply impressed with the clumsiness of my 

 performance as your guide, but I hope that the interest attached to 

 the territory we have explored may, to some extent at all events, have 

 indemnified you for the imperfection of my explanations, and that you 

 leave the Royal Institution this evening with the kind of feeling every 

 one of us has more than once experienced after travelling in similar 

 company over a beautiful country — the guide is forgotten, but the 

 impression of the scenery remains. 



