ORCHIL OR ARCHIL AND CUDBEAR are substantive or non mordants dyes, obtained from Lichens of various species of Roccella growing on rocks in the Canary Islands and other tropical and sub-tropical countries. They used to be made in certain parts of Great Britain from various lichens, but the manufacture of these has almost entirely disappeared. They have been known from early times as dyes. They give beautiful purples and reds, but the colour is not very fast. The dye is produced by the action of ammonia and oxygen upon the crushed Lichens or weeds as they are called. The early way of producing the colour was by treating the Lichen with stale urine and slaked lime and this method was followed in Scotland. Orchil is applied to wool by the simple process of boiling it in a neutral or slightly acid solution of the colouring matter. 3% Sulphuric acid is a useful combination. Sometimes alum and tartar are used. It dyes slowly and evenly. It is used as a bottom for Indigo on wool and also for compound shades on wool and silk. For cotton and linen dyeing it is not used. It is rarely used by itself as the colour is fugitive, but by using a mordant of tin, the colour is made much more permanent. Many of the British lichens produce colours by the same treatment as is used for producing Orchil. Large quantities were manufactured in Scotland from lichens gathered in the Shetlands and Western Highlands. This was called Cudbear. The Species used by the Scottish Cudbear makers were generally _Lecanora tartarea_ and _Urceolaria calcarea_; but the following lichens also give the purple colour on treatment with ammonia:--_Evernia prunastri_, _Lecanora pallescens_, _Umbilicaria vellea_, _U. pustulata_, _Parmelia perlata_. Several others give colours of similar character, but of little commercial value. The manufacture of Archil and Cudbear from the various lichens is simple in principle. In all cases the plant is reduced to a pulp with water and ammonia, and the mass kept at a moderate heat and allowed to ferment, the process taking two or three weeks to complete. RECIPES FOR DYEING WITH LICHENS _To dye Brown with Crotal._ For 6-1/4 lbs. (100 ozs.) of wool. Dye baths may be used of varying strengths of from 10 to 50 ozs. of Crotal. Raise the bath to the boil, and boil for an hour. A light tan shade is got by first dipping the wool in a strong solution of Crotal, a darker shade by boiling for half-an-hour, and a dark brown by boiling for two hours or so. It is better, however, to get the shade by altering the quantity of Crotal used. The addition of sufficient oil of vitriol or acetic acid to make the bath slightly acid will be an improvement (a very small quantity should be used).