6 
BULLETIN" 508, U. S. DEPARTMENT OF AGRICULTURE. 
In Bulletin 129 the averages for beech, birch, and maple included 
yields from heartwood and lumber. Later experiments on tempera- 
ture control have shown that in these experiments yields from lum- 
ber were not strictly comparable with those from heartwood, and 
75 
PERCENTAGE 
Fig. 2.— Relative yields of wood alcohol per cord. (Average yield from heartwood of 
beech, birch, and maple from Indiana and Wisconsin equals 100 per cent.) 
