the north part, if convenient and not too much exposed, may be built against any spare place to that aspect, which will save some expense. The wall should be nine feet high, from the surface of nine inch work. It should have a double roof; for the inside one, an arch made of thin boards, the ends to rest next the wall on the upper shelf, and the outer one a span, covered with slates or tiles. At eighteen inches' distance from the wall inside the house, should be fixed five or six upright posts on each side, to which cross wooden bars may be fastened, whose ends next the wall may be mortised in it. Three tiers of shelves or boxes of the above breadth must be obtained and placed thus: the first or lower tier, two feet from the ground, the second four feet, and the third six feet. A small flue of seven or eight inches should be set on flat bricks, every other one open, commencing at the east, and going round next the path of fourteen inches; which is better than to place the flue immediately under the lower tier of shelves, as this would be prejudicial from its heat, though little danger need be apprehended on this ground, as the maximum heat of the house in the severest season should not exceed 60°; the average about 55°. However, for fear of accidents a tile should be placed at the lower end of the uprights, between them and the flue, by which any apprehension of danger may be removed. The door of the house should have a small slide made at the bottom, which may be used occasionally as a ventilator.

In the above sketch it will be observed that bearers are fixed to support shelves or boxes,

which latter are recommended in preference to filling the entire shelves. The boxes for the purpose should be made of half-inch yellow deal, three feet in height. The depth should be fourteen inches, and the breadth according to the space for the shelves. In the bottom of each box there should be three or four holes, about half an inch in diameter, which will be found useful (though some think otherwise) for two purposes; first, they will admit heat, and secondly, they let out any superfluous moisture which may happen to accumulate during the winter, and which is so baneful to the mushroom in that season. In summer it is not so much to be feared, as light and frequent waterings will be necessary. The compost dung for filling the boxes should be the same as advised for making a mushroom bed (the more horse droppings the better). When it is found to have properly fermented, and to be in a sweet state (the gardeners' phrase), the boxes are to be filled in the following manner: first, lay over the bottom box an inch or so of what may be called flaky dung; if given to spawn, so much the better; and over that five or six inches of the prepared dung before noticed, which is also firmly to be beaten down; over that lay about a dozen small bits of spawn, on which two or three inches more of the prepared dung is to be laid, and beaten down as before, which will make it solid and firm in the boxes of nine or ten inches. It may lie in that state for about a week, for the heat to rise regularly throughout the mass. In the interior it should be examined; and, if it be found very warm, ten or a dozen holes may be made nearly

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to the bottom of the box, with a small pointed stick, for the great heat to evaporate, which it will most likely do in three or four days after, when it may be spawned by pieces an inch and a half square being inserted in the dung in cavities, to be filled up with dung similar to that taken out. The whole is then to be covered two inches thick with a kindly loam or good kitchen-garden earth, not too finely sifted. This should likewise be well beaten down, and the surface covered thinly for a few days with dry litter. Keeping the heat of the house up to 60°, will soon cause the spawn to work, and vegetation to be brought on, so that within a month mushrooms may be expected, in the gathering of which much care will be necessary, by disturbing as little as possible the place where they have risen.

Their after culture will principally consist in keeping up a regular heat during the winter; and should it happen (which, however, is very rare in winter) that any of the boxes are in want of moisture, a very little soft water may be given, which has been placed in the house two or three days before.

Shelves may be erected for growing mushrooms in a warm shed, at the back of a hot or greenhouse; and also in dry, warm cellars, similarly to the house culture: in the latter place, they have been cultivated most successfully in hampers, and, in short, in almost any place where warmth and darkness prevail.

The origin of Sinapis, the most ancient name of this herb, is not precisely ascertained; many botanists consider it arises from its pungent effects upon

the eyes.

Mustard seed was first obtained from Egypt, and has been handed down to the different nations in Europe from time immemorial.

Mustard seed was not common in Queen Elizabeth's reign, but shortly afterwards it came most rapidly into use, at first in its natural state, and then manufactured, as we now have it. It makes an excellent sauce, to be eaten either with fish or flesh. It helps digestion, warms the stomach, and promotes appetite; and, on the whole, must be considered a most wholesome condiment, when mixed with salads, either in winter or summer.

The young mustard, in its green state is highly valued as a salad herb, with cresses, radishes, &c. and its cultivation, for that purpose, is of the first importance. There are two sorts cultivated, the S. alba, or "white mustard," and the S. nigra, or "black mustard."

The flour of the seed of both varieties affords the common mustard for the table, but the latter is chiefly used for that purpose; the first sort is alone cultivated as a salad herb, to be used in its green state. The seeds of both are much used in medicine, and are considered of equal efficacy.

Culture. The white mustard is sown and cul

tivated in the same manner as advised for cress, at

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all times of the year, sometimes every week or fortnight. It can be either sown in a bed or border of light earth, or in shallow drills, very thick, covering it very thinly with the same sort of mould; and in winter, and early in spring, during cold weather, in slight hot beds. It often happens, when this herb is sown in spring, in the open ground, that it is caught with sharp hoary frosts towards morning. When that is the case, a little sprinkling of water before sun-rise, will prevent any ill effects which sometimes follow from the heat afterwards.

The herbs are always cut for use whilst in the seed-leaf, and but a few days old; otherwise they become too strong, and are rank and ill-flavoured.

38. NEW ZEALAND SPINACH.

TETRAGONIA.

This plant was named Tetragonia, from the horned shape of its seed-pods; and Expansa, from its spreading growth.

It is a native of New Zealand, and was introduced into this country by Sir Joseph Banks in 1772, and afterwards principally brought into notice by Mr. John Anderson, gardener to the Earl of Essex, at Cashiobury Park.

The great advantage it possesses is, that of supplying fresh leaves in the driest weather, when the crops of summer spinach are useless. From its rapidity of growth in producing leaves, three or four plants have been found sufficient to give a constant and plentiful supply throughout the season. It is a spreading plant, with numerous branches,