MANUFACTURE OF CHARCOAL. 



129 



kind ouce in three weeks, which is about the time commonly taken to 

 burn a coal-pit.» 



From experiments made by Marcus Bull, about fifty years ago^, dead 

 wood was found to produce the same quantity of charcoal as the same 

 cut in a living state, and the limbs of trees made coal of greater density 

 than the trunk. Stove-dried ebony (specific gravity 1.090) gave 33.82 

 per cent, of charcoal, a greater average than any other kind tried, and 

 its specific gravity was also greater, being .888. Its fracture much re- 

 sembled that of some mineral coals. Stove-dried live-oak (specific 

 gravity .942) gave 32.43 (specific gravity .591); tortoise-shell wood 

 (sepecific gravity 1.212) gave 30.31 (specific gravity .866); cocoa (specific 

 gravity 1.231) gave 28.53 (specific gravity .742), and Turkey box- wood 

 (specific gravity .933) gave 27.24 (specific gravity .622). 



We draw the conclusion that the density and durability of charcoal 

 from different woods are not due to the amount of carbon that they con- 

 tain. The percentage, specific gravity, and weight of charcoal from a 

 great variety of American timber-trees are given in the table of Mr. Bull, 

 upon a subsequent page of this report. 



The percentage of charcoal in the same wood varies according to its 

 ago and the manner in which it has been prepared, whether quickly or 

 slowly. The following results obtained by Karsten, modified in part by 

 the experiments of M. Violette, will illustrate this point. 



Percentage of cJiarcoal of young and old Timber burned elowhj or rapidly. 



1 In September, 1862, the Swedish Government offered a prize of 1,500 rix-dollars for a 

 popular treatise on the manufacture of charcoal and the preparation of peat. In March, 

 18(54, four treatises had been offered, but none were accepted. In June, 1867, seven 

 were presented, but neither received the prize, but the committee decided to give the 

 authors of the two best 850 rix-dollars, upon condition of being allowed to use them. 

 These were placed in the hands of Mr. G. Svedelius, who was designated to prepare a 

 work on charcoal-making, availing himself of whatever information he might bo able 

 to get. His book is entitled " Om Kolning i Mila ; " and it was published in 1872. A 

 translation by Prof. R. B. Anderson, of the University of Wisconsin, with notes by Prof. 

 W. J. L. Nicodemus, of the same institution, was published in New York, in 1875, un- 

 der the title of " Rand-Book for Charcoal-Burners." It relates chiefly tothe construction 

 and burning of metiers or coal-pits. 



The reader is also referred to the following : 



Jrt du Cliarhonmer. By Du Hamel du Monceau, Paris, 1761. 



Memoire sur un Nouvelle appareil pour le carbonisation des Bois en fovct. By E. Dromart, 

 Paris, 1868. 



Carbonisation du Bois et emploi du combustible dans la metallurgie du Fer. By A. Gillot, 

 Paris, pp. 390. 



Carhonisaiion dcs Bois en vases clos et utilisation des products derives. By Camille Vin- 

 cent, Paris, 1873. 



On the maMng of charcoal. Journal Franklin Institute (1831), vii, 71. 



Fei-cy's Metallurgy. (1875.) Pp. 366-414. 



Karaien's System der Metallurgie. Vol. iii. 



The works of Charles David Von Uhr, Thomas Scheever, C. A. Smith, G. A. Molindor, 

 and Ferdinand Von Klein, also contain valuable information upon this subject. 



^Experiments to determine the comparative value of the principal varieties of fuel, &c., 

 page 59. 



9p 



