The substance of the pottery ware, commonly called Delft, the best being made at Delft in Holland, is a whitish clay when baked, and soft, as not having endured a great heat in baking, The glazing is a composition of calcined lead, calcined tin, sand, some coarse alkaline salt, and sandiver; which toeing run into a white glass, the white colour being owing to the tin, is afterwards ground in a mill, then mixed with water, and the vessels, after being baked in the furnace, are dipped into it, and put again into the furnace; by which means, with a small degree of heat, the white glass runs upon the vessels. This glazing is exceedingly soft, and easily cracks. What effects acids will have upon it, the writer of these considerations cannot say; but they seem to be improper for inspissating the juice of lemons, oranges, or any other acid fruits.

The most proper vessels for these purposes are porcelain or China ware, the substances of them being of so close a texture, that no saline or other liquor can penetrate them. The glazing, which is likewise made of the substance of the china, is so firm and close,that no salt or saline substance can have the least effect upon it. It must, however, be observed, that this remark is applicable only to the porcelain made in China; for some species of the European manufactory are certainly glazed with a fine glass of lead, etc.

The stone ware, commonly called Staffordshire ware, is the next to china. The substance of these vessels is a composition of black flint, and a strong clay, that bakes white. Their outsides are glazed, by throwing into the furnace, when well heated, common or sea salt decrepitated, the steam or acid of which flying up among the vessels, vitrifies the outsides of them, and gives them the glazing. This stone ware does not appear to be injured or affected by any kind of salts, either acid or alkaline, or by any liquors, hot or cold. These are therefore extremely proper for all common uses; but they require a careful management, as they are more apt to crack with any sudden heat, than china.

Having thus considered the nature of copper and earthen utensils for the use of the kitchen, we shall proceed to make some few remarks on the poisonous qualities of mushrooms, hemlock, and laurel.

Mushrooms have been long used in sauces, in ketchup, and other forms of cookery ; they were highly esteemed by the Romans, as they are at present by the French, Italians, and other nations. Pliny exclaims against the luxury of his countrymen in this article, wonders what extraordinary pleasure there can be in eating such dangerous food. The ancient writers on the Materia Medica seem to agree, that mushrooms are in general unwholesome; and the moderns, Le-mery, Allen, Geoffroy, Boerhaave, Linnseus, and others, concur in the same opinion. There are numerous instances on record of their fatal effects, and almost all authors agree, that they are fraught with poison.

The common esculent kinds, if eaten too freely, frequently bring on heart-burns, sicknesses, vomitings, diarrhoeas, dysenteries, and other dangerous symptoms. It is therefore to be wished, that they were banished from the table; but, if the palate must be indulged in these treacherous gratifications, or, as Seneca calls them, this voluptuous poison, it is necessary that those, who are employed in collecting them, should be extremely cautious, lest they should collect such as are absolutely pernicious ; which, considering to whose care this is generally committed, may, and undoubtedly frequently has happened. The eatable mushrooms at first appear of a roundish form, like a button ; the upper part and the stalk are very thin ; the under part is of a livid flesh colour; but the fleshy part, when broken, is very white. When these are suffered to remain undisturbed, they will grow to a large size, and ex pand themselves almost toa flatness, and the red part underneath will change to a dark colour.

Small Hemlock, though it seems not to be of so virulent a nature as the larger hemlock, yet Boerhaave places it among the vegetable poisons, in his Institutes; and in his History of Plants, he produces an instance of its pernicious effects. It is therefore necessary to guard against it, in collecting herbs for sallads and other purposes. Attend therefore to the following description:

The first leaves are divided into numerous small parts, which are of a pale green, oval, pointed, and deeply indented. The stalk is slender, upright, round, striated, and about a yard high. The flowers are white, growing at the tops of the branches in little umbels. It is an annual plant, common in orchards and kitchen gardens, and flowers in June and July. This plant has been often mistaken for parsley, and from thence it has received the name of fool's parsley.

The water distilled from the leaves of the common laurel, has been frequently mixed with brandy, and other spirituous liquors, in order to give them the flavour of ratafia; and the leaves are often used in cookery, to communicate the same kind of taste to creams, custards, puddings, and some sorts of sweetmeats. But in the year 1728, an account of two women dying suddenly in Dublin, after drinking some of the common distilled laurel water, gave rise to several experiments, made upon dogs, with the distilled water, and with the infusion of the leaves of the common laurel, communicated by Dr. Madden, Physician at Dublin, to the Royal Society in London ; and afterwards repeated, in the year 173 f, and confirmed by Dr. Mortimer, by which it appeared, that both the water and the infusion brought on convulsions, palsy, and death.

The laurel of the ancients, or the bay, is, on the contrary, of a salutary nature, and of use in several disorders; but the common laurel is a plant of a very destructive kind, and, taken in a large quantity, is a most formidable poison. However, if it be administered with proper caution, and in small proportion, the leaves of the plant are generally thought to be innocent; and therefore, for kitchen purposes, as the flavouring of custards, and such like, the use, in guarded and common moderation, may be continued in perfect safety. The bitter parts of the plants, in which all the noxious properties are supposed to reside, are determined to be the same in quality, and not sensibly different in degree, from the bitter almond, or from the kernels of any of the stoned fruits Linaeus says, that in Holland, an infusion of this kind of laurel is used in the practice of the healing art. Miller also says, that laurel leaves are perfectly innocent. A nice attention, however, is certainly necessary in the use of them.