the name of a vegetable substance which seems to differ from most of the other bodies of that kind in several particulars. It is a substance of an irregular figure, of a greenish brown colour, and somewhat transparent. It trembles at the touch, in the manner of a jelly; but it does not melt when held in the hand. It has therefore somewhat of the characters of a vegetable leaf, but it has neither veins nor fibres. It is found in all sorts of soils; but most frequently in sandy ones, sometimes on the gravel of garden walks, and most usually makes its appearance after rain. It is found only in the summer-months; and retains its humidity and perfect figure as long as it is a moist season, but immediately dries up and withers away on the sun or the wind's affecting it. Many people have supposed this not to be a plant. It appears all on a sudden, and, as it were, by a sort of miracle, either from the earth or clouds; and some have called it flower of earth, others flower of heaven; and the obscurity of its origin occasioned its being held in great esteem among the chemists; some of whom supposed it to contain an universal spirit, capable of converting other metals into gold. Mr Magnol and Mr Tournefort were the first authors who asserted its true origin, and ranged it among the plants. Its nature, however, was never perfectly discovered till Mr Reaumur took it under consideration. He found that it was a leaf which naturally imbibed water in a very particular manner; that when it had enough of this liquor in it, it then appeared in its natural flourishing state; and when it lost this again, it became thin, wrinkled, and was not to be known for the same substance, or, indeed, scarce to be seen at all. Hence appears the reason of its supposed production and sudden decay. If it has, ever so long, lain in the walks of a garden in its empty wrinkled state, it is never taken notice of; but, on a shower of rain, it swells out into its jelly-like state, and on the sun's evaporating that moisture it falls into its undistinguishable state again; and these changes may affect the same plant alternately for many days together.

Mr Geoffroy imagined that he had found roots to the nostoch; but Mr Reaumur positively affirms that it has none. He observed indeed, at certain times, on the surface of certain specimens of this, a vast number of round tubercles of different sizes, which appeared to be the seeds of the plant. These he regularly sowed in earthen pots of mould; and these produced young plants like the parent nostoch: But even these were never discovered to have any appearance of roots; and to try farther whether they had any, Mr Reaumur turned all the plants bottom upwards, and they received no harm from it, but grew just as vigorously as before. If the nostoch has truly no roots, as appears to be very evidently the case, it follows, that it imbibes its nourishment in the manner of sea-plants, which imbibe the water at all their pores. It should seem, that there are two species of this nostoch: the one a plain, flat, leaf; the other curled, wrinkled, and variously undulated: and it is on this last that the fruits which produce the young plants are principally found. It may be, however, that the one of these may be the male and the other the female of the same species, as in many large plants; or possibly the being in the state of fructification alone may make the difference.