[ SI ] 



XVI. Proceedings of Learned Societies. 



KOVAL SOCIETr OF LONDOX. 



PEte. 6. The Right Honourable Sir Joseph Banks, Bart. 

 Pfesident, in the chair. The reading of Mr. Hatnhett's in- 

 teresting paper on artificial tannin was resumed. Effects of 

 sulphuric acid on vegetables in converting them into coal. 

 Resins distilled yield but from -03 to -05 grains coal ; but 

 when treated with this acid from -30 to -60 ; with muriatic 

 acid somewhat less. Gums, whether by distillation or di- 

 gestion with acid, yielded nearly equal quantities of car- 

 bon. The author, from his numerous and very decisive 

 experiments, proceeded with great caution to offer a theory 

 of the formation of pit-coal ; and his own discoveries have 

 enabled him to adduce facts that seem to leave us without 

 hope of ever attaining much more complete knowled'^e of 

 the origin and formation of pit-coal than what he has mo- 

 destly proposed. That all carbonaceous matter is of vege- 

 table origin, has been generally allowed ; and Mr. Hatchctt 

 thinks that the means employed by nature for converting 

 vegetables into carbon has been by slow digestion of great 

 masses exposed to the action of sulphuric acid. To this end 

 he admits that muriatic acid may also have contributed ; but 

 from the much greater universality of sulphuric acid, sulphate 

 of iron (pyrites), &c. in coals, and his synthetical experi- 

 ments, which often gave Co per cent, of carbon from veo-e- 

 table matter by means of this acid, he thence concludes tliat 

 sulphuric acid must have been the more efficient if not the 

 sole agent. Carbon thus formed is found in many parts 

 without bitumen, such as in Kilkenny and Bovey coals, &c. 

 The bitumen is also formed of the resinous parts of vegetables 

 subjected to the slow action of sulphuric acid. 



Feb. 13. Mr. Hatchctt admits that his efforts to form 

 bitumen have not been completely successful, although there 

 can be no doubl of its constituent principles. All synthetic 

 experiments, he observes, are necessarily conducted too 

 rapidly, arid on too small quantities, ever to imitate eflectu- 

 ally the process of nature. To the submarine composts or 

 Vol. 24, Ku. (J3. Fcl. 1S06. F veiTctable 



