Imágenes de páginas

form an acceptable illustration of the letter-press, by giving views of country scenery and seats, towns, and public build. ings.


ART. VIII. Philosophical Transactions of the Royal Society of London, for the Year 1806. Part II. 46o. 178. 60. sewed. Nicol.

Papers on CHEMISTRY and NATURAL HISTORY. CCOUNT of a Discovery of Native Minium : in a Letter from

James Smithson, Esq. F.R.S. to Sir Joseph Banks, Bart. P.R.S.-Mr. Smithson here announces the discovery of minium, or the red oxyd of lead, as a natural production ; and which was found mixed with the carbonate of zinc. He supposes that it is formed from the decay of the sulphuret of lead, as he observed some crystals of this substance, which were externally covered with minium. It is not stated where the oxyd was found, but the paper is dated from Cassell.

Description of a rare Species of Worm Shells, discovered in an Island lying off the North-West Coast of the Island of Sumatra ir the East Indies. By J. Griffiths, Esq. Communicated by Sir Joseph Banks.--- In the year 1797, a considerable earthquake took place in the island of Sumatra ; and during the agitation which ensued in the adjoining parts of the ocean, a bank of mud was laid bare, on which were discovered a number of shells, remarkable for their size and their peculiar conformation. They were tubular, and irregularly tapering; some of the largest of them were above 5 feet long; and the circumference at the base was 9 inches, and that of the smaller end 21 inches. A more particular account of their organization, and of their relation to other marine animals, is given in the subsequent paper.

Observations on the Shell of the Sea Worm found on the Coast of Sumatra, proving it to belong to a species of Teredo ; with an Account of the Anatomy of the Teredo navalis. By E. Home, Esq. F.R.S. -The animal described in the preceding paper having fallen under the inspection of Mr. Home, he conjectured that it belonged to the genus Teredo; and in order to ascertain the truth of his opinion, he procured some living specimens of the Teredo navalis. He presents us with a minute and interesting description of the anatomy of this singular animal, but it would be scarcely intelligible without a reference to the plates.- He points out a peculiarity in its sanguiferous system. The heart admits only of a single circulation, as is the case with all the animals that breathe under water : but in the teredines,


the blood, after it has left the heart, is immediately distributed to the different parts of the body, and is afterward collected in the respiratory organs before it returns to the heart. As the animal possesses no cavity for the reception of water, its respiratory organs are placed on its surface. No nervous system could be discovered: but the organization is in many respects so perfect, that the existence of a brain and nerves seems probable ; although, from the substance of which the animal is composed, we are not able to distinguish the medullary matter.

A portion of the wood which these worms destroy was always found in their stomach : but, from several circumstances, it is rendered probable that this substance does not contribute to their nutrition; and that they are supported entirely by the medium of the sea-water. The animal which was found at Sumatra differs from the common Teredo in being imbedded in mud: but it agrees with it so far in its general structure and appearance, that Mr. Home does not hesitate to consider it as a Teredo ; and from its size he gives it the specific name of Gigantea.--This and the preceding paper are accompanied by characteristic and well delineated plates.

On the inverted Action of the alburnous Vessels of Trees. By Thomas Andrew Knight, Esq. F.R.S.--In his former memoirs, on the Physiology of Vegetables, Mr. Knight had endeavoured to prove that the sap of plants rises through the alburnous vessels, circulates through the extremities during the summer, and, after being in part expended on the growth of the plant, the remainder passes down the bark, and is deposited in the

A fact, however, is mentioned by Duhamel and Hales, which Mr. Knight himself has verified by experiment, and which seemed to militate against this hypothesis. If a circular portion of the bark be removed from the stem of a tree, the part below the wound continues to live, and even to increase in size; a small ring is also formed about the lower lip of the wound, and it makes some advance towards the upper part, although the upper lip throws out a much greater quantity of woody matter. Mr. K. supposes that this growth in the lower part is occasioned by an inverted action in the alburnous vessels, in consequence of which a small portion of the sap passes through them, at the same time that a considerable part of it is retained in the cortical vessels above the wound.

To establish the fact of the inverted action of the alburnous vessels is the principal object of the present paper; and in order to prove this point, the author selected the potatoe, being a plant in which the vessels that convey the ascending sap to the leaves,


and those by which it descends, are in distinct organs. He first made an experiment, in which, by preventing the formation of the tubers, the upper part of the plant was rendered much more luxuriant and prolific; in this manner shewing that the sap was carried from the leaves and stems down to the tubers. He afterward, in a second experiment, carefully removed the whole of the bark from several of the stems, and yet he fouud that the tubers were produced, although they were of smaller than ordinary bulk. Hence he concluded that his position respecting the inverted action of the alburnous vessels is proved ; since, in the latter experiment, no other passage appears by which the sap could be conveyed from the upper to the lower parts of the plant.-We admit that the reasoning is plausible; yet we must be permitted to add that the hypothesis will require the aid of more experiments, before it can be considered as absolutely established.

Description of the Mineral Basin in the Counties of Monmouth, Glamorgan, Brecon, Carmarthen, and Pembroke. By Mr. Edw. . Martin.--The large cavity described in this paper is said to be composed of limestone, and to be the reservoir ir: which all the coal and iron ore of South Wales is deposited. Mr. Martin gives an apparently accurate account of its extent, and of the number and thickness of the different strata which it contains.

Observations on the Camel's Stomach, respecting the Water it contains, and the Reservoirs in which that Fluid is inclosed; with an Account of some Peculiarities in the Urine. By E. Home, Esqa F.R.S.-The peculiar property in the camel's stomach, by which it is enabled to take in a large stock of water before it commences its journies across the deserts, has been long known: but the exact structure and mechanism of the part have never yet been fully ascertained. Mr. Home's paper, however, has now furnished us with a clear and interesting account of this curious piece of comparative anatomy. in order to illustrate the subject, he begins by describing the digestive organs of the ox; which, in many respects, agree with those of the camel in their disposition and uses. In the ox, the first and second stomachs are included in one gener :I cavity ; the drink passes immediately into the second stomach; and it is from this cavity that the food is projected into the mouth, in order to updergo the second mastication. When the food is again swallowed, it is immediately carried to the third stomach; and after having been detained there for some time, it passes into the fourth, which is the immediate organ of digestion. The camel has the same number of cavities with the ox, and their general REY. FEB. 1807.


disposition disposition is considerably similar. The food, however, docs not seem to pass into the second stomach before it is returned into the mouth, but is ejected from a particular part of the first; and after having been chewed, it is directly returned into the third. The drink passes into the second stomach, and, when this is filled, runs over into that part of the first in which the food is lodged; and it would appear that the animal has a voluntary power of discharging the water from the second stomach, so as to moisten the food in the first. When the cud has been chewed, it descends directly to the second stomach, and/ passes immediately into the fourth. The apparatus by which these actions are performed is well explained, and illustrated by some good engravings.

The experiments on the urine, as here communicated by Mr. Hatchett, were performed by Mr. Brande. He was not able to detect any benzoic acid, but he found a little of the uric; and he discovered in it the phosphat of lime. This was likewise found in the urine of the cow; and these fluids agreed, moreover, in not containing any salts composed of soda, Yet these latter salts exist in the urine of the horse and the ass, which again differs from that of the other animals in not exhibiting any traces of the ammoniacal salts.

In mentioning the mode of killing the camel which was the subject of these experiments, by pithing, Mr. Home points out the erroneous manner in which this operation is often executed, and which has led to the discouragement of the practice :

• The operation was performed with a narrow double-edged poniard passed in between the skull and first vertebra of the neck; in this way the medulla oblongata was divided, and the animal instan. tancously deprived of sensibility. In the common mode of pithing catele, the medulla spinalis only is cut through, and the head remains alive, which renders it the most cruel mode of killing animals that could be invented.'

MATHEMATICS, A STRONOMY, &c. Observations upon the Marine Barometer, made during the Exemination of the Coasts of New Holland and South Wales, in the Years 1801, 1802, and 1803. By Matthew Flinders, Esq. Commander of his Majesty's Slip Investigator.--If there be any connection between the wind and weather and the variations of the barometer, it is certainly most desirable that seamen should be acquainted with the laws of that connection: but it is evident that they can only be ascertained by long, patient, and careful observation.

In the paper before us, Capt. Flinders furnishes some valuable temasks, which, as far as they go, will be useful to the mariner;

and atid if other navigators make observations, and cause them like the present to be registered, we shall gradually accumulate sufficient conditions and data for a theory and a system :- some future philosopher may arise who will arrange, compare, and combine the facts which he finds recorded.

On the necessity for every offeer being provided with a barometer, Capt. F. says:

• The barometer seems capable of affording so much assistance to the commander of a ship, in warning him of the approach and termination of bad weather, and of changes in the direction of the wind, even in the present state of meteorological knowledge, that no officer in a long voyage should be without one. Some experience is required to understand its language, and it will always be necessary to compare the state of the mercury with the appearance of the weather, before its prognostications will commonly be understood; for a rise may foretel an abatement of wind,-a change in its direction,- -or the return of fine weather, or if the wind is light and varia. ble, it may foretel its increase to a steady breeze, especially if there is any casting in it ; and a fall may prognosticate a strong breeze or gale, a change of wind, the approach of rain, or the dying away of a steady breeze. Most seamen are tolerably good judges of the ape pearance of the weather ; and this judgment assisted by observation upon the quick or slower rising or falling of the mercury, and upon its relative height, will in most cases enable them to fix upon which of these changes are about to take place, and to what extent, where there is only one ; but a combination of changes will be found more difficult, especially where the effect of one upon the barometer is counteracted by the other; as for instance, the alteration of a mode. rate breeze from the westward with dull, or rainy weather, to a fresh breeze from the eastward with fine weather, may not cause any alteration in the height of the mercury ; though I think there would usually be some rise in this case. Many combinations of changes might be mentioned, in which no alteration in the barometer would be expected, as a little consideration, or experience in the use of this instrument, will make sufficiently evident ; the barometer alone, therefore, is not sufficient ; but in assisting the judgment of the seaman, is capable of rendering very important services to navigation.'

A new Demonstration of the Binomial Theorem, when the Exponent is a positive or negative Fraction. By the Rev. Abram Robertson, A. M. F.R.S., Savilian Professor of Geometry at Oxford.-Since the invention of the law of the binomial theorem, frequent attempts have been made to demonstrate it on clear and exact principles; and the author of the present demonstration has already inserted one somewhat similar, in a preceding volume of the Transactions (viz. that for 1794.) We shall briefly state the principle on which the proof before us is founded.

« AnteriorContinuar »