WATER CRESS, 219 
under hand-glasses, or in drills near a south wall, and in 
summer, when they should be sown once a fortnight, in 
drills, in any cool, shady situation. Table mustard, which 
is made from the seeds of Sinapis nigra, Lin., belongs 
rather to the department of agriculture. Durham mustard, 
which is distinguished for its poignancy, though not re- 
markable for fine color, is said to be made principally from 
the seeds of the common ‘yellow field-mustard or. charlock, 
Stnapsis arvensis, Lin. 
‘Water Cress (Sisymbrium nasturtium).—This is a 
creeping perennial aquati¢ plant, very extensively supplied 
in the English markets. It requires for its proper growth 
a clear stream of shallow water, not more than an inch and 
a half in depth, running overclear sand and gravel. Decp 
and still water, especially if the bottom be muddy, is un- 
favorable. The best situations are in streams near their 
sources, where the water seldom freezes in winter, as here 
they continue to grow and may be gathered all winter. 
In planting, the sets are put in rows about eighteen inches 
apart, and lengthwise with the stream. If the depth of 
water be at first only about an inch, as soon as they begin 
to grow they will so obstruct its course as soon to increase 
it to three or four inches above the leaves, a depth regard- 
ed as highly favorable to the growth of the cresses. It is 
absolutely requisite that the water shall be always run- 
ning, for when the stream becomes obstructed the plants 
cease to thrive. After they are cut three times they be- 
gin to stock, and then ‘the oftener they are cut the better. 
The cress is regarded as a very wholesome raw salad vege- 
table, eaten at all seasons, but more especially in winter 
and spring, when its warm and cordial qualities make it 
particularly grateful. It is frequently found growing 
