Irani 
113 
engagement of which is promoted by frequently stirring 
with a long iron rake, The coak from these ovens* 
though made with the same kind of coal, is very different 
from that produced by the former operation ; this being 
intensely black, very porous, and as light as pumice- stone* 
I am indebted to Mr, Curr, steward to his Grace the 
Duke of Norfolk, for these particulars, who very politely 
attended me through the works in the year 1802* and as- 
sisted me in taking the necessary measurements, &c« 
Parke’s Chem. Cat. 4th ed. p. 443. 
Dr. Watson (2 Essays, 318, et seq.) mentions the fol- 
lowing results of a distillation of 90 ounces of Newcastle 
coal (bituminous) dry oak, box, mahogany and sallow 
Wood, 
Newcastle 
coal. 
oak . 
box . 
mahoga- 
ny. 
sallow . 
produce . 
oz. 12 
57J 
61| 
334 
48 
Liquid 
56 
30 
26| 
27 1 
20® 
Charcoal 
28 
00 
O'* 
8 
35 
27 1 
Loss in air. 
In all cases the nature of the liquid, of the charcoal, and 
the loss, is nearly alike. The liquid consists, 1st. of an 
oily matter swimming at the top : 2d!y. of an acid watery 
fluid. In France, this liquor has been converted into vine- 
gar, when procured from wood. Dr. Bellman, of Phila- 
* delphia, has succeeded in repeating the experiment. 3dly«. 
a more heavy tenacious oil. The liquor procured 
from the distillation of pit- coal, has a stronger odour, is 
more empyreumatic than that from wood. The air in 
both cases, is carburetted hydrogen, or the modem coal 
gas. Four ounces of Liverpool coal yielded me 19 
quarts of this gas ; 4 oz, of fine saw dust, yielded some- 
what above 12 quarts. These facts, with the additional 
ones of the manifest transition from perfect wood to per- 
fect coal in the same piece, as I remember to have seen at 
Whitehaven, leave no doubt in my mind, of coal having 
been originally wood- The turpentine (or spirits of tur* 
P 
