901 



Dyeing Properties of Lichens. 



The second part of Dr. Lindsay's paper ' On the Dyeing Properties 

 of the Lichens ' was read. 



At the last meeting of the Society, Dr. Lindsay stated that, during 

 the last two years, he has been engaged in occasional researches in 

 diflferent departments of the natural history of the lichens, and that 

 lately the subject of their dyeing properties has chiefly occupied his 

 attention. In reference to the latter subject, he has made several 

 extensive series of experiments, with a view to determine the kind 

 and amount of colouring matter furnished by various native species ; 

 the processes being suited, in individual cases, for eliminating these 

 matters, and their special application to dyeing and colouring, &c. ; 

 but his efforts have been greatly circumscribed, by a paucity of 

 materials to work upon. He would therefore be very glad to receive, 

 from members of the Society or others, any spare duplicate specimens 

 of native or foreign species (which, for his present purpose, need nei- 

 ther be rare nor fine), or any kind of practical information bearing 

 upon the subject in question. He gave a short, but comprehensive, 

 view of the present state of the different branches of lichenology in 

 this country, and on the continent ; and showed, from the aggregate 

 amount of information which is at present possessed thereupon, the 

 great necessity there still exists for renewed and extended experimen- 

 tal investigation. The author then considered : — L The vast impor- 

 tance of this humble tribe of plants in the grand economy of Nature, 

 as the pioneers and founders of all vegetation. 2. Their importance 

 to man and the lower animals, as furnishing various articles of food. 

 3. Their importance in medicine, and especially in its past history, 

 at home and abroad. 4. Their importance in the useful and fine arts, 

 and especially in the art of dyeing. 5. Their afl5nities and analogies 

 to other cryptogamic families, and to the Phanerogamia. 6. Their 

 value as an element of the picturesque in Nature. 7. Their typical 

 significance. 



The author then adverted more especially to the subject of his 

 communication, under the ten following heads : — 



\. The colours of the thallus and apothecia of lichens, their causes, 

 and the circumstances which modify and alter them. 



2. History of the application of their colouring matters to the art 

 of dyeing. 



3. Chemical nature and general properties of these colouring 

 matters. 



