CHEMICAL SCIENCE. 231 



person who introduced this, and to whom the greatest credit is due 

 for its production, was Mr. Perkin. Mr. Perkin had seen and admired 

 the tinctorial power of aniline, and he had an ambition to render this 

 fugitive color permanent, and to introduce it into the arts as a dye, 

 and he succeeded admirably. The mode is this : this aniline is a base, 

 and unites with sulphuric acid as ammonia does, and it forms sulphate 

 of aniline. He takes equivalent quantities of aniline and bichromate 

 of potash, and mixes them together, and in a little while, after stand- 

 ing together, they form this very unpromising-looking black powder. 

 You see this black powder here ; it looks extremely unlike a dye. 

 Now, when this color is washed with coal-naphtha, this nasty-looking 

 brown resinous substance is dissolved out of it by the coal-naphtha, 

 and then there remains a still unpromising substance, but which is 

 rather purple in color. When you treat with alcohol this brown 

 powder, which has been washed with naphtha and had the resin 

 taken out of it, it forms with the spirit a strong solution of mauve. 

 This beautiful purple color is obtained in this way, by dissolving out 

 of the brown powder the purple color by means of alcohol ; and it is 

 this purple color which is used largely in dyeing. It is readily soluble 

 in alcohol. 



It is easy to dye with this aniline purple ; in fact, ladies can dye 

 with it perfectly themselves. It is only necessary to use for this pur- 

 pose hot water water so hot that you cannot bear it with your 

 hand, but not boiling. The best temperature is about one hundred 

 and fifty degrees. If you take hot water and add to it a little tar- 

 taric acid and a little of aniline purple, and then place the silk or 

 woollen in it, it becomes dyed. It is easy to attach the color to ani- 

 mal fibre, but not to cotton. I have here the coloring matter, and 

 now I will add to it a solution of tartaric acid, which is necessary to 

 produce the color. After that all I require is to place my silk in this 

 solution, and to rinse it for a little time in it, and you see that it 

 Quickly takes up the color and produces that beautiful mauve which 

 is now so familiarly known. It is, therefore, a substance which is 

 extremely easily applied almost as easily as the carbazotic acid. 



Through the kindness of Mr. Perkin, I am enabled to exhibit to 

 you magnificent specimens of his aniline purple, or mauve, in the dry 

 state and in solution. This brown lump, with the remarkable cop- 

 pery lustre, is mauve in the solid state. Its extraordinary tinctorial 

 powers will be appreciated, if I tell you that this beautiful violet-col- 

 ored solution contains not more than one-tenth of a grain of mauve 

 in a gallon of alcohol. You will also understand the considerable 

 commercial valueof this substance. Weight for weight, this color- 

 ing matter, when pure, is sold at the price of metallic platinum. 



Very little is known regarding the chemical nature of mauve ; its 

 composition is not yet made out, and as a matter of course the pro- 

 cess by which it is formed from aniline remains as yet perfectly unex- 

 plained. 



Magenta is one of the fancy names given to the splendid crimson 

 which is likewise generated from aniline by the action of oxidizing 

 agents. This substance was first observed in purely scientific re- 

 searches, and more especially in the action of tetrachloride of carbon 

 upon aniline. To a French chemist, M. Verguin, the merit is due of 



