Ufefulnefs of wafnng the Stems of 'Trees. 453 
one tenth yearly ; and the increafe of the oak is eight-tenths. 
But calling it only half an inch, then fix years will produce 
above five cubic feet of timber, as the oak is eight feet round, 
and above twenty feet long, and fix pence will pay for the 
wafhing, fo there remains nine fhillings and fix pence clear 
gain in fix years. 
Stratton, ... 
Q&. 29, 178c, 
Von. LXXI. 
