the cloth will receive a perfect dye, and be so fixed that it cannot be separated by any common means.  Thus it will be observed, that the art of dyeing permanent colours depends on this intermediate principle, which is termed a mordant.  These mordants are very numerous; and on a knowledge of them appears to rest the principal secret of dyeing.  The following mode is, however, a very convenient one for makig experiments on fixing the colouring principles of any vegetable extract:  To have several pieces of cloth, woollen, cotton, silk, and linen, dipped in the different mordants, and by keeping a small vessel filled with the colouring solution on a fire in a state a little below boiling, by cutting small pieces of each, and immersing them in the colour, and examining and comparing with each other.  Experiments of this kind are well worth the attention of persons; for, when we refer to this department, we shall find very few plants which are either now, or ever have been, cultivated for this purpose, although it is well known that so many contain this principle.  I have inserted the following, as being known to contain the different colours mentioned; but there are many other plants equally productive of this principle that remain quite unnoticed at present.

539.  Acanthus mollis.  Bear’s-Breech.—­This gives a fine yellow, which was in use among the ancients.

540.  ACTAEA spicata.  Baneberry.—­The juice of the berries affords a deep black, and is fixed with alum.

541.  Anchusa officinalis.  Yellow Anchusa, or blue-flowered bugloss.—­The juice of the corolla gives out to acids a beautiful green.

542.  Anthemis tinctoria.—­The flowers afford a shining yellow.

543.  ANTHYLLIS vulneraria.  Kidney-vetch.—­The whole plant gives out a yellow, which is in use for colouring the garments of the country-people.—­Linn.

544.  Arbutus uva-ursi.  Bear’s-berry.—­The leaves boiled in an acid will dye a brown.

545.  Asperula tinctoria.  Woodroof.—­The roots give a red similar to madder.

546.  Anemone Pulsatilla.  PASQUE-flower.—­The corolla, a green tincture.

547.  Arundo Phragmites.  Common Reed-grass.—­The pamicle, a green.

548.  Berberis vulgaris.  BARBERRIES.—­The inner bark, a yellow.

549.  Bromus secalinus.  Brome-grass.—­The panicle, a green.

550.  BIDENS tripartita.  Hemp agrimony..—­The herb, a good yellow.

551.  Betula alba.  Birch.—­The leaves, a yellow.

552.  Betula nana.  Dwarf-birch.—­The leaves, a yellow.

553.  Betula Alnus.  Alder.—­The bark affords a brown colour; which with the addition of copperas becomes black.