252 SOILS, MANURES, &c. 
nature of the plant, and the ftate it is in 
when burned* 
It is found by experience, that thofe 
vegetables which afford plenty of good 
falts, if properly burned when in right 
feafon, which is when the feed has at¬ 
tained its full fize, but is not perfe£lly 
ripe, will not yield near the fame quan¬ 
tity, nor of fo good a quality, a few 
weeks earlier or later ; there are alfo 
other circumftances to be confidered and 
attended to, which require clofe obfer- 
vation, and confiderable experience to 
underhand and account for properly. 
Much depends on the foil, air, climate, 
and fituation in which the plants have 
grown, and the manner of conducing 
/ 
the operation. 
It has been proved by repeated expe¬ 
riments, that the northern and wehern 
coafls of Great-Britain furnifh plants more 
flrongly 
