If

itself along the ground, or among the clods. This motion is often occasioned by change of dryness and moisture in the air. The animated oat (avena fatua and sterilis,) is a well-known example of it. one of these seeds be placed upon a shelf or window sill in changeable weather, it will, after the lapse of two or three days, be found to have crawled forwards to a considerable distance from its first situation, as follows:-When the seed becomes damp, it swells and lengthens. When the air dries it again, it becomes shorter, but on account of its setæ, it cannot return; therefore it draws the latter end along, and thus at every change in the weather it moves a step forward.

1 and 2. Pappus of the Valerian. 3. Ditto of the Willow Herb and the Groundsel. 4. Ditto of the Dandelion. 5. Ditto of the Goat's Beard. 6. Feather of the Clematis Seed. 7. Sets of the Scirpus, or Bull Rush. 8. Hairs of the Animaled Oat. 9. Awn, or toothed bristle of the Barley Grass, the teeth being magnified.

This is the case too with the awn or beard of barley and wheat, which are set with teeth like a saw, and not merely the seeds of these plants, but the whole ear will crawl away from its parent, if broken off: as is well known to children, who gather the ears of the common barley grass, and putting one end up their sleeve, at the wrist, soon find it at their shoulder.

Besides these admirable contrivances for the dispersion of seeds, there are many more to be looked for in the elasticity and peculiar formation of seedvessels. Animals often assist in accomplishing the same purpose their fur and wool catches the hooks with which the seeds of the goose-grass are provided; while those of the mistletoe adhere to whatever may touch them, owing to their clamminess. It is well known also, that the seeds of numerous berries and small fruit will grow, though they have passed through the bodies of the birds which have swallowed them. Thus we not only witness in seeds themselves the most admirable structures and contrivances for their well-being, but the very habits and necessities of animals are made subservient to the more general dispersion of the vegetables upon which they are fed and nourished.

AN EVER-BURNING FLAME.

A PAPER was lately read at the Royal Irish Academy, by Mr. G. J. Knox, On a Principle for producing an Ever-burning Flame.'-" A belief," he observed," in the discovery of an ever-burning lamp appears to have been prevalent in all ages; and tradition informs us, that lamps have been found in tombs, where they have continued burning for upwards of a thousand years, of which mention has been made in the works of St. Austin, Plutarch, Pliny, Ludovicus Vives, Baptista Porta, and Licetus. The Rosicrucians, who laid claim to the knowledge of everything mysterious, pretended to have re-discovered the secret of their construction, which was supposed to have been buried in the tomb of their founder. Dr. Plott, in a treatise which he has

written upon this subject, alludes to a lamp mentioned by St. Austin in his book de Civitate Dei, which was hung up in the temple of Venus; and to another found in the tomb of Pallas the Arcadian, who was slain by Turnus in the Trojan war, which continued to burn after its removal from the tomb and exposure to the air-proving that these lamps were not supplied from any bituminous source, or volcanic fire. He considers the requisites for an ever-burning lamp to be-a perpetual wick, which might be made of gold wire, or asbestos; and a perpetual supply of fuel, which he imagines the bituminous springs of Pitchford, in Shropshire, or the inflammable gases issuing from fissures in coal mines, would afford. That such could supply fuel for a flame, so long as the bituminous spring existed, or the gas continued to exhale from the mines, is evident; but it no more deserves the appellation of an ever-burning lamp, than does a fire arising from any volcanic source. The desideratum for such a lamp is, that it should contain, within itself, a renovating principle, such as, probably, does the luminous atmosphere encompassing the body of the surr, supposed by Sir William Herschel to be electrical. That electricity was the principle upon which such a lamp could be constructed, having occurred to me some years ago, I reflected upon the different means by which a constant light could be produced from this source, and concluded that, if by an arrangement of metals a thermo-electric current could be produced of sufficient intensity to decompose water, the heat produced by the burning of the two gases arising from the decomposition, would be sufficient, when applied to the alternate metallic junctions, to continue the electrical current of the thermo-electric pile; while the gases, which, in burning, become aqueous vapor, might be condensed by passing through a long tube, through which, being conveyed to the closed vessel in which the water had been originally placed, they would again undergo decomposition, recombination, and condensation. thermo-electric arrangement has been discovered by Professor Botto, of Turin, who has obtained decomposition of water from a series composed of a greater number of wires of platinum and iron. To prevent the apparatus from acquiring in time the same temperature, the alternate junctions of the metals, to which the heat is not applied, might be connected with the pedestal upon which the lamp is placed; and the pedestal be either allowed to rest in a cold situation, or else be connected by wires with some extensive cooling surface."

CHARCOAL AS A MANURE.

Such a

BY MR. LUCAS, BOTANIC GARDEN, MUNICH.

ACCORDING to my promise, I now lay before my readers the experiments I have made in the application of charcoal to another purpose, viz. using it as a mixture with various sorts of earth. It showed here also the same extraordinary effect; and all the plants that have hitherto been subjected to this treatment have been as much distinguished by their luxuriance of growth, as by the more perfect developement of their individual parts. This was particularly the case with tuberous-rooted plants, which, besides their perfect developement, had also a much longer period of vegetation; so that the difference in this respect, between those that were cultivated in their usual soil and those which had a mixture of charcoal, amounted to nearly two months. I was led to this by several trifling circumstances.

A very suitable treatment introduced into this botanic garden of plunging pots with bulbous or tuberous-rooted plants taken up every year, for a few weeks after potting, or till they begin to shoot, in a moderate hot-bed, covering them an inch deep with earth, was applied the previous year. A bed which had been used for sowing the seeds of tender plants in pots, and in which charcoal ashes were used for plunging them in, was appropriated to receive the newly-planted species of A'rum, Begònia, Gésnera, Gloxínia, and Scitamíneæ. with these tubers were plunged to the rim in the frame containing the charcoal ashes, and then covered over with loose mould from a dung bed.

The pots

Before I proceed further, I cannot refrain from recommending this method, which, to my knowledge, has not been long known in German gardens, to all cultivators; for nothing is more contrary to the nature of those plants, than to set them in the open greenhouse to make their first shoots, where they are consequently in a dry situation. Most of them, when treated with a gentle equable warmth, like that of a previously-used dung bed, will be much more fine than if placed in a higher and drier temperature. Watering the tubers before they begin to grow is very disadvantageous, and yet it would be absolutely necessary if the pots stood in a greenhouse: we prevent the evil by making the earth in which the tubers are to be set sufficiently damp, only slightly pressing them down, and immediately covering them with earth in the dung bed. Only when the latter begins to dry, it should be moistened all over with the watering-pot; and this operation should be continued till all the tubers have made shoots, and then each can be watered singly. With respect to preserving them through the winter, I have to observe that these tubers, as soon as they are taken in, should be placed in the greenhouse, not too near the glass, and the earth covered with moss, by which they will be prevented from drying up too soon, and the necessity of moistening the earth obviated. By such treatment, want of success in the cultivation of these splendid ornamental plants can never be complained of. But to our subject.

These tubers, plunged in the ashes, soon shot up vigorously. As they ought to be grown in a high frame in summer, but which could not be immediately prepared, they remained in this low bed, which was only raised, dug up, and kept covered with earth. They absorbed a great deal, and required watering every day. When they were taken up, most of the roots, as may be supposed, had grown over and under the pots; they had penetrated into the charcoal, and grown so strong, that it was absolutely necessary to re-plant the tubers in pots considerably larger in size. I, of course, mixed charcoal with the earth in which they were to be planted, in the proportion of rather more than half. All the above-named species showed extraordinary luxuriance under this treatment; some were particularly rich in their inflorescence, and the green of their leaves was much more intense; in others, the period of flowering was of unusually long duration, so that while others planted in the usual soil had long ceased flowering, these continued to vegetate freely. Very small tubers, from which in the first year no flower was to be expected, flowered very beautifully, as was the case with Gésnera atrosanguínea. The Aröídeæ, namely those with spotted leaves, such as Caladium píctum, C. bícolor, C. díscolor, C. spléndens, C. poe'cile,

C. hæmatostigmum, C. versícolor, &c., excited universal admiration. Several species of Billbérgia and Tillandsia, to which I also added charcoal, soon exceeded in luxuriance those that were growing in common earth. From what was before said of the Cacti, it may easily be supposed that they would flower well in a mixture of charcoal, which experience confirms. Héchtia, stenopétala, which rooted so quickly as a cutting, has since thriven equally well in a mixture of charcoal. The splendid Mexican euphorbias, such as E. fastuòsa and E. fúlgens, showed a very considerable power of growth. Orange trees with yellow leaves, having had a layer of charcoal laid on after the upper surface of earth had been removed, soon recovered their green color; this was also the case with gardenias. We need not be very particular as to the quantity to be used, half charcoal may be used without injury; only care must be taken, as before noticed, that the charcoal should be exposed for a time to the influence of the weather, and the larger pieces removed; and watering should never be neglected, as the greater porosity of earth causes it to dry up sooner.

A very interesting circumstance took place with an old and very sickly plant of the Doryánthes excélsa. After this plant had been falling off for two years, and in reality had no roots but one old and decayed one, it was planted in charcoal, and in the course of three weeks it began to shoot, and is since perfectly recovered; it is growing in a soil of one-third charcoal.

Ferns sown on fine sifted charcoal germinate quickly and well; a number of species come up in the charcoal beds where seed falls, and not only Gymnográmma macrophylla, and Ptèris serrulàta, but other rarer and more valuable species.

A friend of mine in the neighbourhood of Munich uses charcoal ashes for mixing instead of sand, and he assures me that all plants, chiefly hothouse ones, and among the cassias, particularly those with pinnated leaves, acacias, bignonias, &c., succeed extremely well, and have recovered wonderfully from their previous sickly state.

My esteemed principal, the court gardener, M. Seitz, who acknowledges the importance of this use of charcoal, is now putting in practice a number of systematic experiments with different sorts of charcoal, on all the families of plants, and it will only be at the conclusion of these extensive observations, which in spring are to be extended to garden beds, that a well-grounded opinion on the application of charcoal ashes in general can be formed.

Gartin Zeitung, for 1841.

CASSAVA.

CASSAVA bread, conaque, &c., are different names given to the starch of the root of the manioc, (Jatropha Manihot, Linn.) prepared in the following manner in the West Indies, the tropical regions of America, and upon the African coast. The tree belongs to the natural family of the euphorbiacea.

The roots are washed, and reduced to a pulp by means of a rasp or grater. The pulp is put into coarse strong canvas bags, and thus submitted to the action of a powerful press, by which it parts with most of its noxious juice, (used by the Indians for poisoning the barbs of their arrows.) As the active principle of this juice is volatile, it is easily dissipated by baking the squeezed cakes of pulp upon a plate of iron. Fifty pounds of the fresh

juice, when distilled, afford, at first, three ounces of a poisonous water, possessing an intolerably offensive smell; of which, thirty-five drops being administered to a slave convicted of the crime of poisoning, caused his death in the course of six minutes, amid horrible convulsions.

The pulp dried in the manner above described, concretes into lumps, which become hard and friable as they cool. They are then broken into pieces, and laid out in the sun to dry. In this state they afford a wholesome nutriment, and are habitually used as such by the negroes, as also by many white people. These cakes constitute the only provisions laid in by the natives, in their voyages upon the Amazons. Boiled in water with a little beef or mutton, they form a kind of soup similar to that of rice.

The cassava cakes sent to Europe, (which I have eaten with pleasure,) are composed almost entirely of starch, along with a few fibres of the ligneous matter. It may be purified by diffusion through warm water, passing the milky mixture through a linen cloth, evaporating the strained liquid over the fire, with constant agitation. The starch dissolved by the heat, thickens as the water evaporates, but on being stirred, it becomes granulated, and must be finally dried in a proper stove. Its specific gravity is 1.530-that of the other species of starch.

The product obtained by this treatment is known in commerce under the name of tapioca; and being starch very nearly pure, is often prescribed by physicians as an aliment of easy digestion. A tolerably good imitation of it is made by heating, stirring, and drying potato starch in a similar way.

The expressed juice of the root of manioc contains in suspension a very fine fecula, which it deposits slowly upon the bottom of the vessels. When freed by decantation from the supernatant liquor, washed several times and dried, it forms a beautiful starch, which creaks on pressure with the fingers. It is called cipipa, in French Guyana; it is employed for many delicate articles of cookery, especially pastry, as also for hair powder, starching linen, &c.

Cassava flour, as imported, may be distinguished from arrow-root and other kinds of starch, by the appearance of its particles viewed in a microscope. They are spherical, all about 1-1000th of an inch in diameter, and associated in groups; those of potato starch are irregular ellipsoids, varying in size from 1-300th to 1-3000th of an inch; those of arrow-root have the same shape nearly, but vary in size from 1-500th to 1-800th of an inch; those of wheat are separate spheres, 1-1000th of an inch.

FUEL FOR STEAM ENGINES.

A LETTER from St. Petersburgh gives some particulars of a new fuel for steam-engines, discovered or manufactured by a M. Waschinakoff, which offers, it is said, great advantages over coal. We bave, however, heard of so many of these wonderful discoveries in our own country, that we are a little sceptical; still it may be well to publish the facts as stated. The first experiment made, on a large scale, with this fuel, to which M. Waschinak off has given the name of carboléin, was on board the English steamer Syrius, on its last voyage from Cronstadt to London; and the results are given as follows:-A consumption of 44b. (English weight) of carboléin per hour, for every horse-power of the engine, produced thirteen revolutions per minute, and yielded a speed of more than seven English

miles per hour; whilst, on the same voyage, with 7lb. of English coal, of best quality, the wheel gave only twelve revolutions, and the vessel made no more than 6 miles an hour. The flame of the new fuel, says Captain Waters, who commanded the Syrius, was so great, that they were constantly obliged to reduce it to one-third.-A cubic foot of the best Newcastle coal weighs nearly 55lb., whilst the same measure of carboléin weighs nearly 56tb.4,480,000lb. of coal, the usual provision for steam vessels passing between England and the United States, occupy a space of 81.884 cubic feet; but 2,480,000lb. of carboléin yielding the same effect, take only 51.694 cubic feet; so that the latter combustible would effect a saving of room to the extent of 30.190 cubic feet, available for merchandize or passengers. The freight from England to North America, and vice versâ, being at the rate of 2s. 6d. per cubic foot, making 5s. both ways, the space economized, would produce, for the two passages, an excess of freight amounting, in value, to £7,547., deducting from this sum £643 for the greater price of the carboléin necessary for the two voyages over coal, and allowing, besides, £1,940 to the account of any deficiency which might occur in filling up the space saved, with goods or passengers, there would still be a clear gain, at the lowest calcula tion, of £5,000 by the use of the new fuel.Athenæum.

MEMORANDA.

Action of Sulphur on Iron.-Colonel A. Evans has remarked that although sulphur has so strong an action on heated wrought iron, as immediately to form holes in it, yet it does not at all affect grey cast iron. A plate of wrought iron, 63 of an inch in thickness, heated to whiteness, and held against a roll of sulphur 6-10 of an inch in diameter, was, in fourteen seconds, pierced through with a perfectly cylindrical hole. Another bar, about two inches in thickness, was pierced by the same means in fifteen seconds. Good steel was pierced even more rapidly than the iron; but a piece of grey cast iron, well scaled and heated till nearly in fusion, was not at all affected by the application of sulphur to its surface, not even a mark being left. A crucible was made of this cast iron, and some iron and sulphur put into it; on applying heat, the iron and sulphur soon fused together, but the cast iron underwent no change. Ann. de Chim.

Lead Ore in Glamorganshire.-The Cambrian observes" It seems somewhat extraordinary, that in this speculating age, when such vast sums are sent to seek, and too often to sink, their fortunes in a far distant region, that our home treasures should be so disregarded, even our own county of Glamorgan. Lead ore, of the purest quality, which can even be scraped up by the sides of the road, in ditches, and abundantly a few feet beneath the surface of the soil, still continues to be dormantscience, capital, the gigantic power of the steamengine, all alike dormant. St. Hilary, Colvinstone, Langan, Penlline, and other parishes, abound in lead ore. Take up a handful of earth near any of the old pits, and it is full of lead ore. Twenty-five years ago, it was asserted by the oldest persons then living, that the working of the lead mines on the Penlline Court Estate was suspended (now from eighty to one hundred years ago) in consequence of the overwhelming pressure of water, years before the steam-engine, with its gigantic power, came into

play, and that the main vein of ore at the time was thirty-seven inches in thickness. The ore was then carried above half a mile to be washed, and taken back again to the smelting-house, which adjoined the pits. The steam-engine would now admit of the ore being washed upon the spot."

Gold, Silver, and Copper Coin.-The following is the number of pieces of various sorts coined at the Mint from the 1st of January, 1837, to the 31st of December, 1840:- Sovereigns, 4,395,373; half-sovereigns, 434,778; -crowns, nil; ;-- - halfcrowns, 567,072; - shillings, 9,741,600;- sixpences, 7,524,000 ;-fourpences, 6,070,680;-(the total number of fourpences issued being 10,325,320 ;) pence, 174,720; - halfpence, 1,075,200; and farthings, 10,913,280.

Coal Dust as Manure.-Mr. W. H. B. Webster, Surgeon, R.N., of Ipswich, has paid some attention to this subject, the details of which may be found in the last part of the Transactions of the Society of Arts, London. The analogy between the constituent principles of coal to that of oily matter led Mr. W. to conceive that it might be advantageously employed as food for plants. The complete insolubility of coal dust seems to be the inseparable objection to its utility as a manure, and Mr. W. is inclined to believe, from a long continued series of 'observations, that the slender filamentous radicles of plants (in other words spongeoles) have a power in all respects equal, if not superior, to small electrogalvanic wires of low intensity, which, by slow continued action decompose most substances that are presented to them, and among others that of coal dust. Mr. W. also further states, that, whatever the vital principle may be, a lower grade cannot be assigned for it in the scale than that of electrogalvanic influence; and we are not, says he, assuming too much for the vital action of the radicles, when we claim for them a power equal to that of small galvanic wires, which can and do effect a decomposition of coal dust. He then proceeds to demonstrate the fact, that coal dust is not inimical to vegetation, and this he accomplishes, by filling a series of garden-pots with fine coal dust, and planting and sowing a variety of plants therein, as potatoes, onions, &c. In all of them the vegetation was extremely vigorous and luxuriant. also filled hyacinth glasses with coal dust, and put bulbs therein, supplying water as required; and the result, when compared with those without the coal dust, was very marked and evident; large, healthy, strong plants being produced, and admired by many.

He

Animalcules contained in Chara.-Thuret has observed in the interior of the anthers (globules) of chara vulgaris and C. Hispida, flexuose, transparent, chambered filaments of unequal length, in which are contained animalcules at first motionless, but after a time they move and struggle to release themselves from their prison. In this they do not always succeed, although their twisted position attests the efforts made for disengagement. They appeared like a spirally-rolled thread of three to five curves, with two appendages, bristles, or tentacula of excessive tenuity, which the animalcule incessantly agitates with great rapidity.-Microscopic Journal.

Air contained in Snow.-According to Dalton, the quantity of oxygen in the atmosphere diminishes in proportion to the distance from the surface of the earth. Gay-Lussac, however, did not find this to

be the result of his experiments-for air which he obtained at a height of upwards of 20,000 feet, contained the same proportion of oxygen as that procured from the neighbourhood of Paris. M. Boussingault has found, in common with others, that air obtained from snow contains less oxygen than that of the atmosphere. But this holds good with regard to the snow of the Andes, as to that of Paris. He admits, however, that this may not be the composition of the air as it exists in the snow; because, in order to obtain this air, it is necessary to melt the snow; the gas of the flask comes in contact with the water, little if at all impregnated with air resulting from the melting and it is well known that in such circumstances oxygen dissolves more readily in water than the azote, and that the air with which water is saturated is richer in oxygen than that of the atmosphere. M. Dumas and M. Boussingault are at present examining the composition of atmospheric air.-Athenæum.

British Museum.-The number of visitors admitted to view the general collections from Christmas 1839 to Christmas 1840, amounts to 247,929, being 32,921 less than in the previous year. The number of visits made to the reading rooms, for the purpose of research or study, during the past year, amounts to 67,542, being 1,674 less than in the year before. The number of visits by artists and students to the galleries of sculpture, for the purposes of study, amounts to 6,354, being an increase of 1,513 to the previous year. The number of visits made to the print room, in 1840, amounted to 6,717. The total number of additions to the zoological department, by purchase or otherwise, 21,976 specimens.-Report, House of Commons, March 8, 1841.

Meteoric Paper.-The microscope has been ably employed by Ehrenberg to determine the composition of the meteoric paper of 1686, and which he states is a product of conferve and infusoria, now existing on our globe. According to this author, the substance known by the name of meteoric paper, and which fell near Rauden, in Curland, in 1686, is formed of filaments of conferva crispata, thickly matted together, with remains of a nostoc, twentynine well-preserved species of infusoria, and the cases of daphnia pulex. Of the twenty-nine infusoria eight only have silicious lorica; the rest have soft coverings. In the meteoric paper of Schwazenberg, Ehrenburg found conferva capillaris, C. punctalis, and oscillatoria limosa, along with twenty distinct species of infusoria, &c. In a mass found in Sweden, Edogonium vesicatum (Link) infusoria, and the pollen of some conifere were discovered.-Microscopic Journal.

Preservation of Meat.-At the last meeting of the Academy of Sciences, M. Gannal presented an important essay, which is likely to produce a considerable sensation amongst the public as well as in the scientific world. M. Gannal has been for many years occupied with the idea of preserving meat by injection. Thus, 4th. weight of saline mixture injected into the carotid artery of an ox penetrates all the vessels, and prevents a putrid decomposition. M. Gannal presented two legs of mutton preserved two years since by this plan, and which were found to be perfectly sweet. M. Gannal employs for this purpose muriate of alum. This discovery is considered as valuable in preserving provisions for the navy.-Times.