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bit, produced a still more terrible and speedy dissolution. Tbe poisonous principle of the other upas tree, or anthiuris ioxicaria, is a bitter substance, soluble in water and alcohol. This bitter substance is composed of a colouring matter, of an acid, and a particular substance, which seems to be the active part of the poison, and which these chemists suppose to be a vegetable alkali. This vegetable alkali has the same effect on the animal economy as the poison of the upas tree, but is much more energetic. It differs somewhat in its action from strychnia, tbe former producing convulsions, with relaxation, and not being so speedy in its destroying effects as the latter, which seems suddenly to arrest with a single convulsion the whole functions of life.

THE BARK TREE. The following is an extract from a Report lately made by the celebrated traveller, Baron Humbold t,'to the

.Academy of Sciences at Paris, on a work of Mr. Auguste St. Hilaire, who returned to France not long ago, from the Brazils, bringing with him 7000 plants, 2000 birds, 16,000 insects, and 130 mammiferous animals. "The discovery," says the Baron, " of the true cinchona in the eastern part of South America, far from the Cordilleras, must strike those who attend to the distribution of vegetables over the surface of the globe, and the geological causes which have influenced it. At present not a single

: species of cine/tuna is known to exist, flot even the exostema, either in the mountains of Silla de Conceal, where the befariu, the aralia, and

, the thibaudia, and ether mountain plants of New Grenada grow, or in

, the wooded mountains of Caripe or of French Guiana. This total want of the cinchona and exostema genders on the table land of Mexico, and on the eastern parts of South America, north of the equator, is more surprising, because the Antiles are not destitute of species of bark

i, trees. The quinina of the Cordil

.. leras does not extend further east

in the northern hemisphere than the

72 degree of longitude west from Paris, or the mountains of Micachisla of the Sierra Nevada of Merida. The cinchona ferruginea, C.Vellozii, and C. RemVjiano of Mr. St. Hilaire grow on the table lands of the province of Minas-Geraes, at the height of 100 metres, in a temperate climate between 22° and 18" of southern latitude. They are regarded as certainly indicating the presence of minerals containing iron wherever they grow. The bitter and astringent bark of those quinina (Quina da Serra) ef the mountains of Brazil resembles very much in its flavour tbe quinina of Peru and of New Grenada. Their febrifuge qualities are not, however, so strongly marked as those of a still more celebrated tree, the stiychnos pseudoquina, which is found in the diamond districts, in the deserts of Goyaz, and in the western part of Minas-Geraes. Of all the medicinal plants of these vast countries, the Quina do Campo, or strychnos pseudoquina, is most in use, and best known. The physicians of Brazil give the bark in powder and in decoction; and it is a beneficent gift of nature to a region where intermittent fevers are unfortunately too frequent. The virtues of the strychnos pseudoquina, as a febrifuge, are found not to be inferior to the best species of the cinchona of the Cordilleras; and though the former has not at Brazil entirely superseded the use of imported bark, it may one day be exported to Europe in great quantities.

M. Vauquelin has analyzed the strychnos, and found in it a peculiar acid, but neither brucia quinina, nor any of the poisonous • principle found in the strychnos nux vomica. It was before known that strychnos potatorum was destitute of this deleterious principle, and that the pulp of the fruit of the nux vomica might be eaten without any danger. The various parts of a plant do not all contain the same principles, and if in the same family of plants, in the same gender, and in plants of an analogous structure, we do not find very striking chemical differences, it must be recollected that such anomalies are more apparent than real; for, according to the experiments of M. M. Gay Lussac and Thenard, on vegetable chemistry, the same elements, with very small variations of proportion, are differently grouped, and produced different combinations, the effects of which on the nervous system may be diametrically opposite.

BATTLES AND LOVES OF
LEECHES.

Mankind are more indebted to the labours of the husbandman than tbey in general confess; for not only their comforts but Their morality depends on his exertions. It is found by experience, that humanity and hunger cannot exist together; and in spite of the tirades of ascetic philosophers against enjoyment, it is clear that full bellies are the great source of peace and love and good-will amongst men. it is quite a mistake to suppose that Cannibals eat their brother men out of pure love to human flesh, and a natural delight in cruelty. They only do it as the half-starved sow is known to feed on her young—out of hunger; and wherever they can find somewhat to satisfy this craving, though it be by toils and dangers, amidstquaking ice-bergs, like those of the Esquimaux, and though their food be only whale blubber, they prefer this to steeping their hands in human blood. The effect of full bellies in promoting harmony and tranquillity is wonderfully apparent at present in this country. We now and then feel a little puff of religious discord, but the fierce spirit of sectarianism is gone to sleep in the lap of animal indulgence. Radicalism and terrorism have both been choked by cheap bread; and it is plain, if there were plenty of potatoes and rags in Ireland, we should hear nothing of either Orange or Catholic Associations, White-boyism, Blne-boyism, and the other isms and schisms ef that unhappy land. All have their origin in the people having incautiously multiplied faster than the murphies; and the emptiness of their stomachs is the" cause of the dis

content in their hearts. It is well known that the same law applies to animals as well as men; and dog will only eat dog when he is on the point of starving. A French author, M. Noble, has lately shown that the same fact is true of leeches. As long as these little water serpents can find the blood of man or beast to suck, they Jive in great-harmony with one another, go on depositing their eggs, and propagating their kind, nine, ten, eleven, and even as many as fourteen in a family.— When, however, ■ they have exhausted their stock, like the Irish, they turn on one another, and, like cannibals, feed on their own dead. "Among the causes (says this physician) which augment very much the mortality of leeches, must be placed those battles (of course they are naval battles, though the physician has not described their Nelson or their Van Tromp,) which they fight when they are too numerous in the same vessel, or when their food is not sufficient; the weakest fall, and the others feed on them. To obviate this inconvenience, it was found only necessary to place them in a large reservoir, supplied with a stream of fresh water. —When the winter cane, like Laplanders, they buried themselves in the mud; and when the returning warmth of spring brought them forth, they were attended with a great number of young ones. Holes were found in the sides of the reservoir, and in each of these there was deposited a cocoon of an oval form, and as large as the cocoons of the silkworms. They were of the texture outside, and had the appearance of very fine sponge. Several of them were opened; some were found empty, and their interior was compact and polished, as if covered with a coat of varnish; others were filled with a transparent and homogeneous jelly. In the most advanced, nine, ten, and even fourteen young leeches were found."—Bulletin ties Sciences Technologiques.

To Correspondents in nur next.

London: published by Knight and CTCey,55, Paternoster-row.—Printed by B. Bcusiey, Bolt-court, Meet-street.

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Chemical Apparatus.

ing and Productive Cascade Analysis of Scientific Journals.

nals of Philosophy for July ib.

Dictionary of Chemistry '.'...' 278

To make Ice in the midst of Summer 279

Queries ib.

Extraordinary Engine for propelling

Vessels.... 280

Explosive Engine ,,,,,,,,,,, ib.

CONTENTS.
The Absorb- On Purifying the Air of Apartments 281

Chemistry as a Science. Art. XVII.

Bismuth. Mercury 283

Sound has no Velocity 285

More Poisons 287

Perkius outdone, or new Inventions ib.

Mr. Tait's Invention disputed. 288

Chemical Society ib.

To make Fire from Water ,,, ib.

T

CHEMICAL APPARATUS.

THE ABSORBING AND PRODUCTIVE

CASCADE.

Description of the Plate.

This is an apparatus invented and employed by Mr. Clement, a celebrated French chemist of the present day, to promote the absorption or solution of gases. It is known that this takes place in proportion to the pressure on the absorbingliquid, the extent of surface exposed to the absorbingaction,and to the length of time in which it is exposed. If the pressure, however, is very great, the vessels are apt to burst, and therefore, in general, the object chemists have had in view has been to strengthen the influence of the two other principles we have just mentioned. Mr. Clement employs the following means:—A B is a long cylinder full of a great number of small glass or porcelain balls, about one-third of an inch in diameter. This cylinder is fixed in another of a much greater diameter, in which a hole, C, is made corresponding to the lower extremity of A B, and with which two small tubes, D E, communicate, one being intended to introduce the gas, the other to empty the liquid. From a reservoir, F, a stream of water flows by means of the tube, G, which is supplied with a stopcock, so that this stream may be regulated at pleasure. The water in its descent is detained by all the little balls, which it wets successively, and is a considerable time before it reaches the bottom; on the other hand, as the gas arises it occupies all the empty space, is much divided and subdivided, and, as it also is detained in its progress npwards, the time it is in contact with the water is very considerable. The author of this invention supposes, that it is more than three hundred times more efficacious in promoting the absorption of a gas than the ordinary apparatus. This he calls the absorbing cascade, and to it he adapts another apparatus, which he calls the productive cascade. It is intended to produce gas for a

considerable period of time, and in a more convenient and less expensive manner than by the ordinary methods. Thus for example: to prepare chlorine, a large vessel, H, provided with four mouths or holes, isfilled with the oxide of manganese broken into large pieces; the mouth, I, is connected with a leaden vessel, K, containing com? mon salt and sulphuric acid. .By the tube, L, a small stream is made to flow from the reservoir, M, which gradually moistens the whole surface of the pieces of manganese, and permits the muriatic acid gas to attack and dissolve it very easily. The chlorine which is produced passes by the tube, N, into the absorbing cascade, while the muriate of manganese is carried off as it forms by the water through the tube, O, into the reservoir, P. By using this apparatus there is no occasion to reduce the manganese to powder, and a much larger quantity may be operated on at the same time, without the operator being under the necessity of frequently renewing the charge of materials and dismounting his apparatus. We should suppose that many of our readers who have chemical operations to perform, will find Mr. Clement's a very useful method.

ANALYSIS OF SCIENTIFIC JOURNALS.

ANNALS OF PHILOSOPHY FOR JULY.

Great complaints have lately been made of the inefficiency and barrenness of scientific journals; and on this subject a literary periodical thus expresses its opinion: "The existing scientific journals have, it strikes us, many grievous defects; first, men of acknowledged scientific talent rarely contribute to them, or at least do not put forth their strength in the contributions they transmit. Such persons are no doubt unwilling to have the fruits of their most pro^ found researches presented to the world mixed, up with such amass of crude and frivolous speculation as we generally find in these jourrials. Secondly, we think the editors mistake their proper vocation. Their leading object ought' to be to give us clear and popular accounts of the discoveries made at home and abroad, Showing, to the unlearned as well as the learned, the effect, application, and true value of each new truth added to art or science. Instead of this, we have the original speculations (often the mere sweepings of the study) of fourth and fifth-rate men, upon subjects of ninth and tenthrate importance, repulsively abstruse, and forbiddingly technical; and, along with these, whole pages, rough and round, from " the excellent work" of A., or B., or C, already in every body's hands, and given without note or comment. The editors ought to know that half a sheet upon a subject easily intelligible, and bearing on the business of life, such as steam navigation or gas light, is worth a volume upon the anatomy of gnats' legs, or the double refraction of a wren's eye. What is merely curious should not be excluded, but kept in its proper place. Nor is a good idea the worse for being new; but still it is better to be useful and popular, than to be original and trashy. Philosophical journals ought to be addressed not exclusively to men of profound science, who are few in number, and will not be satisfied with the scraps they get in such works, but to the mass of persons whom business or curiosity interest in scientific. pursuits, without having taste or time for deep researches. Such journals should be considered as the links that connect the learned with the industrious—the strainers and digesters through which the truths of philosophy must pass to fit them for assimilating with the system of active and busy life. The success of the Mechanics' Magazine, the Chemist, and other periodicals of that description, shows how ample the field of usefulness is in this department, if our journalists of a higher class would get into the tight track."—Scotsman.' As the present Number of the

Annals bears the name of Mr. Children, as an additional editor, we presume that it has been placed under a new administration, and that it has been found necessary to put forth greater vigour, or quit the field. If the editors of the Mechanics' Magazine and the Chemist, have no other gratification, they at least know that their, exertions have compelled other editors to set about improvement. The scientific literature of the country will be henceforth much better, and for this beneficial change the world will be greatly indebted to exertions, which (we will not stoop to the commonplace cant of zeal for the public) were made for ouj own benefit. We cannot, however, yet compliment the editors of the Annals, much as we may be disposed to imitate the parliamentary vice of sacrificing a principle to a flattering phrase, with having made any conspicuous improvement in the matter of their journal. There is much the same quantity of what is merely curious, and nearly the same deficiency of what is really useful. We first meet with—

A BIOGRAPHICAL ACCOUNT OF ASSESSOR JOHN GOTTLIEB GAHN.

Why Mr. Children, who we conjecture is the author of this paper, chooses to prefix Mr. Gahn's title, which is unusual in England, though very common in Germany and Sweden, we are at a loss to discover., What should we think of" Biographical Memoirs of President of the Royal Society Davy," or " ExciseCollector Wordsworth I" and if these modes of expression are strange, why, we ask, does Mr. Children introduce a similar mode, because the man was a foreigner, and had his title prefixed to his name in his own country? But, not to be hypercritical, we shall take from the paper an outline of Gahn's life.

J. G. Gahn was one of the most distinguished chemists Of the last fifty years. He was b.prn on Aug. 17th, 1745, at Woxna iron works, in South Helsingland, and was the son of Ilanns Jacob Gahn, trea

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