400 CARBONIZING TURF 
the case when turf is carbonized in Ireland, to 
supply the hearths of some country smithies. I 
began, then, by submitting the turf to a dry dis- 
tillation in iron retorts, five feet deep to four 
feet diameter, covered with strong sheet iron 
caps, to which I adapted cast iron pipes. I soon 
found, however, that the quantity of auxiliary 
mineral fuel required to burn the turf, owing to 
the distance of seven miles from the nearest pits, 
rendered this method too expensive to be con- 
tinued. 
I expected that the acid would compensate 
for the price of the coal, but I could never get 
it above two or three degrees; besides, the 
pyrolignous alcohol diluted in the acid existed in 
a very small proportion. The tar, which was 
comparatively abundant, contained the greater 
part of the spirit, but the low price of tars in 
general offered me no encouragement to proceed. 
I knew, by the discoveries made by my coun- 
tryman, Mr. Merle, in 1834 and 1835, that cer- 
tain species of turfs gave a richer and superior 
gas than either coals or oils, and I convinced 
myself that the peats in my neighbourhood were 
of an excellent quality for such a purpose, but I 
