26$ FERN. 
common purple kind is the hardiest of the whole. 
This is frequently cultivated in our gardens ; and, if 
screened from the north-east winds, it ripens, even 
with us, in tolerable perfection. 
The wood of the fig-tree is of spongy texture, and, 
when charged with oil and emery, is much used on the 
Continent by locksmiths, gun-smiths, and other arti- 
ficers in iron and steel, to polish their work. It is 
almost indestructible, and on this account was formerly 
employed in eastern countries as coffins for embalmed 
bodies. 
CLASS XXIV. CRYPTOGAMIA. 
280. FERN, or BRAKE (Pteris aquilina), is a well-known 
cry ptogamous plant, which grows wild on heaths, in woods, and 
in barren places. 
Though this plant is an extremely troublesome weed 
to the farmer, from the roots penetrating deep into the 
ground, it is applied to various uses in rural ceconomy. 
When cut and properly dried, it serves as litter for 
horses and cattle; and it supplies the place of thatch 
for covering the roofs of cottages and stacks. Where 
coal is scarce, it is used for the heating of ovens and 
burning of lime-stone. 
The ashes of fern, from their yielding a tolerably 
pure alkali, are frequently used by manufacturers of 
glass, particularly in France. And, in some parts of 
our own country, the poor people mix these ashes with 
water, and form them into round masses which they 
call fern balls. These are afterwards heated in a fire, 
and then, with water, are made into a ley for the scour- 
ing of linen. They thus furnish a cheap substitute for 
soap. 
Swine are fond of the roots of fern, and will feed 
