VOL. Lvii.] Philosophical transactions. 4&t 



answer the same purpose of that expensive article among the dyers, called 

 orchell, or canary weed, which is the lichen roccella of Linn. sp. pi. 1622. 



As the object was of consequence, the society was very desirous of being fully 

 informed of the nature and appearance of this useful dye : and therefore several 

 curious gentlemen of the society were desired, against the next meeting, to bring 

 some specimens of true orchell. Accordingly some specimens were obtained 

 from the orchell dyers in Southwark, and laid before the society. At the same 

 time Dr. Maningham, a member of that society, produced beft>re the society a 

 specimen, in a paper with orchell written upon it, from Mr. Miller of Chelsea, 

 likewise as the true orchell : but, on examining it, it proved to be the corallina 

 nervo tenuori fragiliorique internodia nectente of Sir Hans Sloane's History of 

 Jamaica, vol. i. tab. '20, fig. 4. Some disputes arising on the different appear- 

 ance of the specimens, I took the liberty to inform the gentlemen present, that, 

 having lately made some experiments on corallines, I believed that Mr. Miller's 

 specimen was a coralline, or animal substance, and the lichen roccella, or dyers' 

 orchell, was a vegetable ; and in order to convince the society of the difference 

 I called for a lighted candle, and having first set fire to the lichen roccella, it 

 yielded the same smell that burnt vegetables usually do ; but when the coralline, 

 which was Mr. Miller's specimen, was burnt, it filled the room with such ai* 

 offensive smell, like that of burnt bones, or hair, that the door was obliged to 

 be opened, to dissipate the disagreeable scent, and let in fresh air. 



Another argument that Dr. Pallas offers the world of the vegetable nature of 

 corallines, or rather a proof of their not being of an animal nature, are Count 

 Marsigli's chemical experiments on the corallina officinalis, (Hist. Mar. p. 73), 

 where he says it neither contains animal oil nor volatile salts. But, to prevent 

 such plausible arguments from misleading mankind, I determined to have fair and 

 accurate experiments made on this substance. Accordingly I applied to Mr. 

 Peter Woulfe, f. b. s., a gentleman distinguished for his great knowledge in 

 chemistry ; and in order to have the specimens fresh from the sea, I applied to 

 a worthy member of this society, the earl of Hillsborough, for Mr. Potts, the 

 secretary to the Post-Ofiice, to procure me a sufficient quantity of the corallina 

 officinalis from the sea-coast near Harwich : this parcel, about 2 months ago, 

 I sent to Mr. Woulfe ; and in answer have received the following letter, with an 

 account of his experiments made on it. 



" Sir, — I took 12 ounces Troy of the corallina officinalis, picked clean from 

 every extraneous substance, and put it into a clean stone-coated retort ; the re- 

 tort was set in a reverberatory furnace, and an adopter and quilled receiver luted 

 to it : the fire was very gentle for the first 8 hours ; in which time, half an ounce 

 and 1 8 grains of a transparent and almost colourless liquor came over, which was 

 set aside for examination. The fire was then increased, and in 6 hours time 



