114 On the characteristic Properties of Tannin. 



An inquiry into the nature and formation of coal was my 

 first object when I discovered the artificial tanning sub- 

 stance, and, considering the importance of the latter, it 

 will not appear surprising that it should immediately have 

 engaged the principal part of my attention. 



In addition to the experiments which have been related in 

 the three papers upon this subject, I intended to have de- 

 composed the diflerent varieties, to have compared their gases 

 and other products with those of the natural substance called 

 tannin, and especially to have endt^avoured to discover more 

 cEConomical methods of obtaining the artificial product ; for, 

 exclusive of speculative science, this appears to be an object 

 of consequence, not only respecting that useful and valuable 

 branch of manufacture to which it immediately relates, but 

 also as the means of preventing, or at least of diminishing, 

 the premature destruction of timber in a country, where, on 

 account of its population, as well as on account of its ma- 

 ritime position, every oeconomy in such an article should be 

 most rigidly observed. 



But, for the present, I intend to relinquish this subject to 

 such as may consider it worthy of attention ; whilst, as I 

 have already stated, I entertain very sanguine expectations 

 that eventually it will prove oeconomically useful ; and should 

 any be inclined to pursue the inquiry, I would recommend 

 particular attention to those processes which relate to the 

 roasted vegetable substances, and to peat. 



Almost any refuse vegetable matter, such as twigs, dead 

 leaves, &c. will serve for the former; whilst the latter, as I 

 have shown, does not require to be roasted, and in many, 

 especially the northern counties, peat is found in such abun- 



in external characters appeared somewhat similar to the mixture of asphaltum 

 and resin founc^ at Bovey, to wliich I have given the name of Resin-asphal- 

 tum. These eiptriments sir James Hall intends to resume, and it is my earnest 

 wish that he would do so ; for although I am strongly inclined to believe that 

 the mineral coals have generally, if not always, been formed by some humid 

 process, yet it is impossible to foresee the results which may be obtained from - 

 animal and vegetable bodies subjected to the elTects of heat modified by com- 

 pression, as the principles of these bodies may be acted upon, and may be 

 made to re-act on each other, under circumstances which until now have not 

 been imagined. 



dance. 



