172 HORSE-RADISH. COMMON MUSTARD. 
is cultivated in several of the clothing districts of 
England. 
As soon as the plants are in a sufficient state of ma- 
turity, they are gathered. The leaves are picked off, 
and submitted to the action of mills, somewhat similar 
to the mills that are used for the grinding of oak-bark. 
In these they are reduced to a pulp. The woad is then 
laid in small heaps, which are closely and smoothly 
pressed down. After continuing about a fortnight in 
this state, the heaps are broken up, and their substance 
is formed into balls, which are exposed to the sun to be 
dried. When the balls are perfectly dry, they are ready 
for use ; and are employed, not only in dyeing blue, 
but also as the basis of several other colours. 
185. HORSE-RADISH (Cochlearia armoracia) is a well- 
known kitchen- garden plant, which grazes wild by the sides of 
ditches and the hawks of rivers, in never a I parts of the north of 
England. 
The root of horse-radish is much used for culinary 
purposes. It is remarkable for great pungency both of 
smell and taste. When scraped, it is mixed .with pickles 
to heighten their flavour, and is eaten with roast beef, 
fish, and several other kinds of food. Whenever more 
of the roots are dug out of the earth at once than are 
immediately wanted, they may be preserved for some 
time, in a juicy state, by putting them into dry sand. 
Horse-radish is also in considerable repute as a me- 
dicine, and is a powerful stimulant, whether externally 
or internally applied. Notwithstanding this, we are in- 
formed by* Dr. Withering, that an infusion of horse- 
radish in cold milk is one of the best and safest cos- 
metics that are known. 
SILIQUOSA. 
186. COMMON MUSTARD is made from the powdered 
seeds of a plant (Siisapis nigra), which grows wild in corn-fields 
and by road sides, in most parts of England, and is known by 
its yellow cruciform flowers, with expanding calyx, and its pods 
being smooth, square, and close to the stem. 
