In Sweden, Scotland and other countries the peasantry use a Lichen, called _Lecanora tartarea_ to furnish a red or crimson dye. It is found abundantly on almost all rocks, and also grows on dry moors. It is collected in May and June, and steeped in stale urine for about three weeks, being kept at a moderate heat all the time. The substance having then a thick and strong texture, like bread, and being of a blueish black colour, is taken out and made into small cakes of about 3/4 lb. in weight, which are wrapped in dock leaves and hung up to dry in peat smoke. When dry it may be preserved fit for use for many years; when wanted for dyeing it is partially dissolved in warm water; 5 lbs. of Korkalett is considered sufficient for about 4 Scotch ells of cloth. The colour produced is a light red. It is used in the dyeing of yarn as well as of cloth. In Shetland, the _Parmelia saxatilis_ (Scrottyie) is used to dye brown. It is found in abundance on argillaceous rocks. It is considered best if gathered late in the year, and is generally collected in August. Linnaeus mentions that a beautiful red colour may be prepared from the Lichen _Gyrophora pustulata_. _G. Cylindrica_ is used by Icelanders for dyeing woollen stuffs a brownish green colour. In Sweden and Norway, _Evernia vulpina_ is used for dyeing woollen stuffs yellow. Iceland Moss, _Cetraria Islandica_, is used in Iceland for dyeing brown. _Usnea barbata_ is collected from trees in Pennsylvania, and used for an orange colour for yarn. A general method for using lichens is suggested by Dr. Westring of Sweden in his _Experiments on Lichens for Dyeing Wools and Silks_: "The Lichens should be gathered after some days of rain, they can then be more easily detached from the rocks. They should be well washed, dried, and reduced to a fine powder: 25 parts of pure river water are added to 1 of powdered lichen and 1 part of fresh quick lime to 10 parts powdered lichen. To 10 lbs. lichen half a pound sal ammoniac is sufficient when lime and sal ammoniac are used together. The vessel containing them should be kept covered for the first 2 or 3 days. Sometimes the addition of a little common salt or salt-petre will give greater lustre to the colours." This method can be followed by anyone wishing to experiment with Lichens. Dr. Westring did not use a mordant as a rule. Where the same species of Lichen grows on both rocks and trees, the specimens taken from rocks give the better colours.