CAROLINE. Pray is not _coke_, (which I have heard is much used in some manufactures,) also a bituminous substance? MRS. B. No; it is a kind of fuel artificially prepared from coals. It consists of coals reduced to a substance analogous to charcoal, by the evaporation of their bituminous parts. Coke, therefore, is composed of carbon, with some earthy and saline ingredients. _Succin_, or _yellow amber_, is a bitumen which the ancients called _electrum_, from whence the word electricity is derived, as that substance is peculiarly, and was once supposed to be exclusively, electric. It is found either deeply buried in the bowels of the earth, or floating on the sea, and is supposed to be a resinous body which has been acted on by sulphuric acid, as its analysis shows it to consist of ah oil and an acid. The oil is called _oil of amber_, the acid the _succinic_. EMILY. That oil I have sometimes used in painting, as it is reckoned to change less than the other kinds of oils. MRS. B. The last class of vegetable substances that have changed their nature are _fossil-wood_, _peat_, and _turf_. These are composed of wood and roots of shrubs, that are partly decomposed by being exposed to moisture under ground, and yet, in some measure, preserve their form and organic appearance. The peat, or black earth of the moors, retains but few vestiges of the roots to which it owes its richness and combustibility, these substances being in the course of time reduced to the state of vegetable earth. But in turf the roots of plants are still discernible, and it equally answers the purpose of fuel. It is the combustible used by the poor in heathy countries, which supply it abundantly. It is too late this morning to enter upon the history of vegetation. We shall reserve this subject, therefore, for our next interview, when I expect that it will furnish us with ample matter for another conversation. CONVERSATION XXII. HISTORY OF VEGETATION. MRS. B. The VEGETABLE KINGDOM may be considered as the link which unites the mineral and animal creation into one common chain of beings; for it is through the means of vegetation alone that mineral substances are introduced into the animal system, since, generally speaking, it is from vegetables that all animals ultimately derive their sustenance. CAROLINE. I do not understand that; the human species subsists as much on animal as on vegetable food, and there are some carnivorous animals that will eat only animal food. MRS. B.