The fact is now clearly established, that a concrete vegetable juice of the nature of coutchouc can be obtained from a diversity of trees and plants; probably from many more than is at present suspected; and that these concretes differ from each other in regard to the intenseness or remifsnefs of some of their constituent qualities; some of them pofsefsing the elastic quality, and some of them the viscid quality, in a much more eminent degree than the others; and so on in regard to other particulars. But, as these very peculiarities may render one superior to the other for particular purposes, it is of much importance that they should be accurately compared with each other in all these respects. Dr. Roxburgh's observations may serve as a beginning to this set of experi→

ments.

4

As various plants are now proved to contain this substance, it will naturally stimulate the attention of those who explore unknown regions, and direct them to investigate the qualities of milky juices wherever they occur; and in the course of these investigations they may be led to discoveries of very great importance; for the virus of these juices, considered in a medical point of view, are very powerful; witness opium. It is probable, that among the milk-bearing plants some may yet be discovered nearer home than any

that are at present known, particularly on the coast of Africa, that may afford a true elastic coutchouc equal in all respects to that of America; which would be indeed a valuable discovery. I have already mentioned the circumstance that renders this not only probable, but the next thing to a certainty. Were 2.2 C 2

ligiosus et indica, Hippomane biglandulosa, Cecropia peltata, &c.

"The coutchouc of the ficus religiosa the Hindoos consider as the most tenacious vegetable juice that they are acquainted with; from it their best bird-lime is prepared. I have examined its qualities as well as those of ficus indica and artocarpus integrifolia, by experiments similar to those above related, and found them triflingly elastic when compared with the American and Urceola elastica; but infinitely more viscid than either: they are all inflammable, though in a less degree, and show nearly the same phenomena when immersed in mineral acids, solution of alkali, alcohol, fat, and efsential oils; but the solution in cadjeput oil could not be separated by spirits of wine and collected again, like the solutions of the Urceola and American coutchoucs."

I have inserted the above valuable memoir more at large than is usual with me, because of the many important inferences that may be deduced therefrom by every reader who adverts to it. Whether the cadjeput oil (with which I am entirely unacquainted) be ever introduced as an article of commerce into this country, I know not, and will be glad of any farther information respecting it by such of my readers as are qualified to give it; but if it be not, it certainly deserves to be imported for that purpose; for many are. the uses that might be made of it in surgery and arts for the purposes above specified, could it be obtained here, at first for the sake of experiment, and afterwards in quantities to serve the various purposes in works at

The fact is now clearly established, that a concrete vegetable juice of the nature of coutchouc can be ob÷ tained from a diversity of trees and plants; probably from many more than is at present suspected; and that these concretes differ from each other in regard to the intensenefs or remifsnefs of some of their constituent qualities; some of them possessing the elastic quality, and some of them the viscid quality, in a much more eminent degree than the others; and so on in regard to other particulars. But, as these very peculiarities may render one superior to the other for particular purposes, it is of much importance that they should be accurately compared with each other in all these respects. Dr. Roxburgh's observations may serve as a beginning to this set of experi

ments.

As various plants are now proved to contain this substance, it will naturally stimulate the attention of those who explore unknown regions, and direct them to investigate the qualities of milky juices wherever they occur; and in the course of these investigations they may be led to discoveries of very great importance; for the virus of these juices, considered in a medical point of view, are very powerful; witness opium. It is probable, that among the milk-bearing plants some may yet be discovered nearer home than any that are at present known, particularly on the coast of Africa, that may afford a true elastic coutchouc equal in all respects to that of America; which would be indeed a valuable discovery. I have already mentioned the circumstance that renders this not only probable, but the next thing to a certainty. Were

the Society of Arts to offer a suitable premium to the person who should make this discovery, and ascertain the plant that produces it, and where it grows, it would no doubt stimulate research among those sea. faring men who visit these coasts, that might be attended with very beneficial consequences to the coun

try.

To the Editor of Recreations in Agriculture, &c.

SIR,

ON DESCRIPTIVE POETRY.

I HAVE Occasionally read in your valuable repository of Recreations, critical remarks on poetry; which always appeared to me perfectly consistent with the nature of your work: for poetry, at least in its sublime, which is its true, sense, being conversant in the different appearances of the material, as well as the intellectual world, and loving such studies and employments as are natural, may be very properly supposed to fall under your notice, and will necefsarily administer pleasure to the majority of your readers.

As poetry, in general, according to Aristotle, consists in imitation, it might be no useless investigation, to inquire, in what such imitation consists; to distinguish the genuine imitator of nature from the mere imitator of other poets; to point out the excellencies of the former character; and to shew the marks that particularise the latter. But these subjects would lead into a wide field of inquiry, and, after all, it would only be over beaten ground.

fall under your consideration, is pastoral and descriptive, both of which have their appropriate place under the general head of imitation; consisting either in a representation of the manners and passions of persons employed in country occupations, or in the painting of rural appearances, and in the reviving of familiar afsociations and genuine imprefsions; such as will naturally engage the attention of him who surveys rural scenes with a poet's eye, and feels them, if I may so exprefs myself, with a poet's feeling.

Several of our English writers, were it proper to go into nice discriminations, I should certainly beg leave to exclude from that clafs of poets (though without refusing them their proper praise) to which the title of their compositions, or the courtesy of their readers have advanced them.

To such writers I should refuse this palm, in proportion as I saw the appearances described by them were not congenial to the countries whence they took their observations; or, as the manners and pursuits were difsimilar; in proportion, too, as I could trace, not from hasty and inaccurate conclusions, but from circumstances well authenticated, and indubitable marks of imitation, that their paintings were not their own, but copies from other artists. This has been done by several critics with respect to Pope, when compared with Virgil; and, indeed, in part by Pope himself; it has been also performed with regard to Virgil, when compared with Theocritus, by a German critic.

On this principle we call Theocritus a truly rural and descriptive poet, because he is supposed to have described manners, customs, and appearances, as it