sions. He began with ascertaining the difference of the length of Mr. Whitehurst's pendulums, vibrating 42 and 84 times in a minute, by Mr. Troughton's divided scale. He then investigated the weight of a cubic inch of distilled water, in a known state of the atmosphere. His next object was to determine the proportion of these weights and measures to those that have: been usually considered as the standard of this kingdom. The chief authoritative standards of longitudinal measure are those preserved in the Exchequer, in the House of Commons, at the Royal Society, and in the Tower. Of these several standards, the author has given a very particular account. He observes that the first alone bear legal authority, and have been in use for more than 200 years; the last are considered as a copy of them. The two others are of modern date, and bear no statuteable authority:- but, as they were made by Mr.G." Graham and Mr. J. Bird, artists of acknowleged reputation, they are held in high respect. The mean length of Mr. Graham's standard made in 1742, compared with the scale divided by Mr. Troughton, was found to be 35,9973 inches. The standard of Mr. Bird made in 1758, compared with Mr. Troughton's divisions, was = 36,00023 inches, the thermometer being at 64°. From a table exhibiting a comparative view of the Exchequer standard of 1588 and of Mr. Troughton's scale, it appears ' that the antient standards of the realm differ very little from those that have been made by Mr. Bird, or Mr. Troughton, and consequently, even in a finance view, (if one might look so far forward,) nothing need be apprehended, of loss in the customs, or excise duties, by the adoption of the latter.'

The author proceeds to shew the proportion of the weights which he used, compared with the standards that were made by Mr. Harris, assay-master of the Mint, under the orders of the House of Commons, in the year 1758. The mean weight of the Troy pound, which was the standard adopted by Mr. Harris, appeared to be 5763,715 grains by Mr. Troughton's weights, the barometer being at 29,72 inches and thermometer 67°; and the mean weight of the 21b. Troy, the thermometer being 68°, was 11527,70 grains, and 1lb = 5763,85 grains; consequently the mean weight of 1 lb. is deduced from all the trials to be 5763,78 grains: so that Mr. Troughton's weights are too light by i in 1523,92 grains. On the whole, our author concludes that the difference of the length of two pendulums, such as Mr. Whitehurst used, vibrating 42 and 84 times in a minute of mean time, in the latitude of London, at 113 feet above the level of the sea, in the temperature of 60°, and the barometer being at 30 inches, is = 59,89358 inches of the parliamentary standard; whence all the measures of superficies

:

and capacity are deducible. He has also determined that, agreeably to the same scale of inches, a cubic inch of pure distilled water, when the barometer is 29,74 inches, and the thermometer is at 66o, weighs 252,587 grains by Mr. Troughton's weights; or, on account of the correction above stated to be necessary of I in 1523,92 grains, 252,422 parliamentary grains; whence all the other weights may be derived. The three objects which the author has accomplished, by the elaborate investigation contained in this paper, are briefly as follow:

First an invariable, and at all times communicable, measure of Mr. BIRD'S scale of length, now preserved in the House of Commons; which is the same, or agrees within an insensible quantity, with the antient standards of the realm. 2dly, A standard weight of the same character, with reference to Mr. Harris's Troy pound. 3dly, Besides the quality of their being invariable, (without detection,) and at all. times communicable, these standards will have the additional property of introducing the least possible deviation from antient practice, or inconvenience in modern use."

Sir George closes this curious paper with a table exhibiting the prices of various necessaries of life, together with that of day-labour, in sterling money, and also in decimals, at different periods from the Conquest to the present time, derived from respectable authorities; with the depreciation of the value of money inferred from them:-To which is added, the mean appreciation of money, according to a series of intervals of 50 years, for the first 600 years, and during the present century, at shorter periods, deduced by interpolation. This table is the result of judgment and labour, and contains, in a small compass, much curious and interesting information.

In an appendix, we have an account of 3 other scales, divided into inches or equal parts, and executed by the late Mr. Bird; one was the property of General Roy, the second belonged to Mr. Harris of the Tower, and is now in the possession of Alex. Aubert, Esq. and the third was presented by Mr. Bird's executors to the Royal Society. These are compared with Mr. Troughton's scale. We have also an examination of the standard rod of Henry VII. constructed about the year 1490, and a comparative view of the lengths of 8 several standards and scales, reduced to one and the same measure, viz. that of Mr. Troughton.

To the class of Philosophical Papers we may refer the usual Abstract of a Register of the Barometer, Thermometer, and Rain, at Lyndon, in Rutland, for the Year 1796; by Thomas Barker, Esq. and the Meteorological Journal of the Royal Society for

1797.

ANATOMICAL.

ANATOMICAL and CHEMICAL PAPERS.

Observations on the Foramina Thebesii of the Heart. By Mr. John Abernethy, F. R.S. By adverting to the circumstances under which the principal coronary vein terminates in the right auricle of the heart, we shall readily perceive that the flow of blood through that vessel must be occasionally impeded; and that the difficulty will be much increased, when the right side of the heart is more than ordinarily distended, in consequence of any obstruction to the pulmonary circulation. Such an obstruction, by distending the right side of the heart and hindering the circulation in its nutrient vessels, must probably produce disease in it, if it were not prevented by that structure of the animal economy which the author explains in this paper. On eight comparative trials, made by injecting the vessels of hearts taken from subjects whose lungs were either much diseased, or in a perfectly sound state, he found that, in the former, common coarse waxen injection readily flowed into all the cavities of the heart, but principally into the left ventricle; while, in many of the latter, he could not impel the least quantity of such injection into that cavity. When the left ventricle was opened, and the injection removed, the foramina Thebesii appeared both numerous and large, and distended with the different coloured wax, which had been impelled into the coronary arteries and veins. In a natural state of the heart, the principal foramina Thebesii are to be found in the right cavities of that organ: but these cavities, even in a state of health,, being liable to an uncommon distention in consequence of muscular exertion, which sometimes forces the venous blood into the heart faster than it can be transmitted through the lungs, similar openings on the left side become necessary; which openings, in their natural state, are capable of emitting blood, and of relieving the plethora of the coronary vessels, and yet are not of sufficient size to give passage to common waxen injections: -but, in a distended state of the right cavities of the heart, which is almost certainly occasioned by a diseased condition of the lungs, these foramina, leading into the left cavities, become enlarged; and thus the plethoric state of the nutrient vessels of the heart, and the consequent disease of that important organ, are prevented. Thus the ingenious author accounts for the variety that occurs in the size and situation of these foramina, which appear to belong both to the arteries and veins. The injection which was employed was too coarse to pass from one set of vessels to the other, and yet the different coloured injections passed into the cavities of the heart unmixed.

In the sequel of this paper, the author explains another circumstance relating to the animal economy, which serves to prevent diseases of the heart, that would otherwise inevitably succeed obstruction in the pulmonary vessels. In subjects who had been afflicted with pulmonary consumption for some time previous to their disease, the foramen ovale was found to be open; and, in several instances, the aperture was sufficiently large to admit the passage of a finger.

*As the septum auricularum is almost constantly perfect in subjects whose lungs are healthy, (says Mr.A.) I cannot but conclude that the renewal of the foramen ovale is the effect of disease; nor will the opinion appear, on reflection, improbable; for the opening becomes closed by the membranous fold growing from one edge of it, till it overleaps the other, and their smooth surfaces, being kept in close contact, by the pressure of the blood in the left auricle, they gradually grow together. But, should there be a deficiency of blood in the left auricle, and a redundance in the right, the pressure of the latter on this membranous partition will so stretch and irritate the uniting medium, as to occasion its removal, and thus a renewal of the communication between the auricles will again take place.'

Hence the author concludes that, in those men, or animals, who are accustomed to remain long under water, this opening will be either maintained or renewed:' but the continuance of life does not depend on this circumstance alone; for, if the blood be not oxygenated in the lungs, it is not fit for supporting the animal powers. Mr. Abernethy (in our opinion) very justly controverts the truth of an experiment related by Buffon; who says that he caused a bitch to bring forth her puppies under warm water, and then suddenly removed them into warm milk, in which state he kept them for more than half an hour, and then took them out alive; and that the submersion was repeated without injury. Questioning the truth of the fact, Mr. Abernethy immersed a puppy, soon after its birth, under water of the animal temperature. In 60 seconds, the animal lost all power of supporting itself, and would shortly have perished, if it had not been removed into the air. The experiment was repeated, but the animal could not maintain its existence by the circulation of unoxygenated blood. Animals, accustomed to remain long under water, probably first fill their lungs with air, which may, in a partial manner, oxygenate their b'ood during their submersion. The true statement of this subject may probably be, that the circulation of venous blood will destroy most animals in a very short space of time; but that custom may enable others to endure it, with very little change, for a longer period.'

Experiments Experiments and Observations, tending to shew the Composition and Properties of Urinary Concretions. By George Pearson, M. D. F. R. S.

These experiments and observations are introduced by a brief historical account of the progress of discoveries in this part of science. Hence we learn that the experiments, which have been hitherto made, however considerable in the aggregate, rather afford indications of what remains to be done than demonstrations of the nature of animal concretions. Never theless, the subject is important; and the investigation of it, both as it is connected with chemical philosophy, and as it may lead to more efficacious and innocent practice in diseases that proceed from these concretions, cannot fail of being useful. The substance to which Dr. P.'s observations principally relate is that which he finds, by his experiments, to be very generally a constituent of both urinary and arthritic concretions. It is a substance obtained by dissolving it out of these concretions, by lye of caustic fixed alkali, and precipitating it from the solution by acids. In this way, Scheele separated this matter; but he did not consider its importance, nor of course at all investigate its properties.' Without reciting any of the numerous and well-conducted experiments, which the author made in the course of his inquiries, we shall satisfy ourselves with giving an abstract of the principal conclusions which he de duced from them.

• It appears that at least one half of the matter of the urinary concretions subjected to the above experiments united to caustic soda, and was percipitated from it by acids. This precipitate does not indicate acidity to the most delicate tests; and, as it is inodorous, tasteless, scarcely soluble in cold water, does not unite to the alkali of carbonate, of potash, of soda, or of ammoniac, nor to oxide of mercury, nor to the lime of lime-water, nor decompound soap, or prussiate of iron, and, as its combination with caustic soda resembles soap, more than any double salt known to consist of an acid and alkali, this precipitate does not belong to the genus acids. As this precipitate could not be sublimed, without being decompounded, like animal matter, and also for the reasons mentioned in the last paragraph, it cannot be the same thing as the acid sublimate of Scheele, or the succinic acid. As it does not appear to be putrescible, nor form a viscid solution with water, it cannot be referred to the animal mucilages. On account of its manner of burning in the air, under the blowpipe, and its yielding, on exposure to fire in close vessels, the distinguishing products of animal matter, (especially ammoniac and prussic acid,) as well as an account of its affording a soap-like matter with caustic soda, this precipitate may be considered as a species of animal matter; and from its composition being analogous to that of the substances called, in the new system of chemistry,