Recent Foreign Inventions. Concentrating the Coloring Matter of Fresh or Spent Madder.

Scientific American 26, 8.3.1856

E. J. Hughes, of Manchester, patentee.

This inventor takes a fibrous or porous substance, such as cotton, wool, or sponge, and steeps it in a mordant calculated to combine with the coloring madder, &c.- When the material is thoroughly saturated, he subjects it to the action of the necessary processes to remove the acid and thoroughly precipitate the mordant on the material, as is usually done in calico printing. He then puts the material thus prepared into water with the madder or any preparations thereof. he heats the water, and leaves it a sufficient time to allow all the coloring matter to combine with the mordant fixed on the material, after which he exposes the material to the action of a strong acid, such as sulphuric, muriatic, &c., either slightly or much diluted, for a sufficient length of time to dissolve or decompose the mordant, and carbonize or dissolve the fibroud or porous material. When this is accomplished he puts it on a filter and washes and neutralizes it until the acid is removed. The residue is then the concentrated coloring matter he wishes to obtain.

For the delicate pinks on fine muslins this is a good plan of obtaining a refined extract of madder color; but for common purposes, the process appears to be a very expensive one.