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Art. VIII. Description of a Set of Halos and Parhelia, seen in the Year 1771, in North-America. By Alexander Baxter, Esq. These phænomena occurred the 22d of January, about two in the afternoon, at Fort Gloucester, on the river of Lake Superior, fix miles above the Falls of St. Mary's, and as much from the mouth of the river. Besides the principal halo round the fun, there was a luminous circle, parallel to the horizon, passing through the centre of the halo, in which were five mock funs. Opposite to the sun was a luminous cross, and in the zenith a semicircle, with the convex part turned toward's the sun. .

Art, IX. Observations of the Transit of Mercury, May 4, 7786, at Drefden. By M. Köhler.

Art. X. Observations of the Transit of Mercury, at St. Pe. tersburg. By M. Runovski. :

Art. XI. 'Account of the Strata observed iu finking for water at Boston in Lincolnshire. By Mr. James Limbird. Without specifying the different strata, or the depth of each, we shall only observe that at 474 feet from the surface, chalk and gravel were found; and at 468 feet, salt water was drawn up; circumstances, which tend to prove that this part of the illand had long been covered by the sea. Should the work be resumed, there is the strongeft reason to expect that fresh water will yet be found, and which will rise to the surface.

Art. XII. Observations of Miss Herschel's Comet, in August and September 1786. By the Rev. Francis Wollaston, LL.B.F.R.S. In examining this comet Mr. Wollaston made use of his fyftem of wires, which seems to have answered in a manner not unsatisfactory; and he has given a series of obser'vations on the different stars which the comet preceded or followed.

Art. XIII. An Account of a Thunder-storm in Scotland; with some Meteorological Observations. By Patrick Brydone, Efq. F.R.S. This thunder-storm, which proved fatal to one man, and a few animals, is described by Mr. Brydone with great perfpicuity, and with his usual neatness.

Arti XIV, On finding the Values of Algebraical Quantities by converging Serieses, and demonstrating and extending Propositions given by Pappus and others. By Edward Waring, F.R.S. As this paper consists of a series of depending calculations, it is impoflible either to abridge, or give any particular account of it. :

Art. XV. Experiments on the Production of Dephlogisticated Air from Water with various Substances. By Sir Benjamin Thompson, Knt. F.R.S. In these Experiments Sir Benjamin Thompson employed raw filk, which is found to

collect

collect air rapidly in water, exposed to the light. He discovered that light alone, independently of heat, was the efficient caufe of the production of air ; and that the quantity produced was in proportion to the intensity of light, whether the latter proceeded from the sun, or was collected by mirrors from lamps. Sheep's wool, eider down, hare's fur, and cotton wool, shewed fimilar properties with fikk in regard to the collecting of air.' Human hair, and the ravellings of linen, seemed to exert very little power in this respect, but from whatever substance the air was supplied, the water, in consequence of the process, changed to a greenish or a yellowish hue; and the colour appeared to be produced entirely by animalcules. .

The air from silk was better than that which was procured from plants in a state of vegetation; and, what was remarkable, the power of the lilk did not seem to be exhausted by the repetition of the experiments ; nor was its appearance altered in any respect. When the animalcules were formed, pure air was produced even by water itself, without the addition of any other substance. · Art. XVI. An Account of the Discovery of two Satellites revolving round the Georgian Planet. By William Herschel, LL,D. F.R.S. These satellites were discovered on the irth of January, 1787, in consequence of an improvement made by Dr. Herschel on his telescope, by which it gained more light So far as he could follow them by his observations, he thinks that one performs a synodical revolution in about eight days and three quarters, and the other in nearly thirteen days and an half.

Art. XVII. Remarks on Mr. Brydone's Account of a remarkable Thunder-storm in Scotland. By the Right Hon. Earl Stanhope, F.R.S. This phænomenon being so well authentic cated, his lordship attempts to account for the circumstances attending it by the laws of electricity, the operation of which, in the present instance, he confiders as a demonstrable fact.

Art, XVIII. Concerning the Latitude and Longitude of the Royal Observatory at Greenwich; with Remarks on a Memorial of the late M. Cassini de Thury. By the Rev. Nevil Maskelyne, D.D. F.R.S. M. Cassini de Thury, in a memoir presented to the Royal Academy of Sciences, had asserted that the latitude of Greenwich was not ascertained within 15". The astronomer royal, with a becoming zeal of doing justice to the memories of his learned predecessors, and to himself, evinces that the latitude of Greenwich has been fixed with considerable precision. He explains the various methods employed for this purpose, both by his predecessor Dr. Bradley and himself; whence it appears, from a mean of two determinations in different ways, that the latitude is 51° 28' 40". Dr. Maskelyne, in examining the causes of M. Cassini's mistake, imputes it to a passage in a memoir of the Abbé de la Caille on astronomical refractions, and the latitude of Paris, in the French Memoirs for 1755. It is probable that the error arose from some little defect in the inftruments, and the table of refractions employed by the Abbé. The limits of a Review will not permit us to exhibit the numerous remarks and calculations of the Astronomer Royal on this subject; but we cannot conclude without observing that he has conducted the investigation with great precision and perspicuity.

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Art. XIX. An Account of the Mode proposed to be followed in determining the relative Situation of the Royal Obfervatories of Greenwich and Paris. By Major-General William Roy, F.R.S. and A.S. It is impossible to convey any adequate idea of this method without the assistance of the plan which accompanies it; but from the distinguished abilities of those who are engaged in the operation, the accuracy of the instruments with which they were furnished, and the proof of attention which has already appeared in the mensuration of the base by the same author, we may be assured that the relative situation of the two observatories will be afcertained with the greatest exactness.

Art. XX. An Account of Three Volcanos in the Moon. By William Herschel, LL.D.F.R.S. This paper, though short, is, like the other ingenious communications of the same author, highly interesting to curiosity. Dr. Herschel has, with his telescope, discovered some luminous fpots on the dark portion of the moon, where they frequently change their appearance, and sometimes even disappear. They must therefore be produced by fome active power in the body of that planet; which power, from its light, we may confidently affirm to be fire. Hence Dr. Herschel, with great reason, supposes those spots to be volcanos. The largest is judged to be nearly three miles in diameter.

Though our delay in giving an account of the Philosophical Transactions was originally occasioned by accident, we now have reason to think that it has been productive of some advantage. For the narrative, being thus regularly continued, affords at least an opportunity of tracing more distinctly the progress of science. We shall therefore proceed in the detail without interfuption; and comprise, in a few more numbers of our Journal, what yet remains unnoticed of the Philosophical Transactions, down to the present time. .

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ART. VIII. An Inquiry into the Small-Pox, medicat and political;

wherein a successful Method of treating that Disease is proposed, the Cause of Pits explained, and the Method of their Prevention pointed out; with an Appendix, representing the present State off Small-Pox. By Robert Walker, M. D. Fellow of the Royal College of Surgeons, Edinb. 8vo. 6s. boards. Murray, London; Creech, Edinburgh. 1790.

HOW much the improvement of medicine has been ob

ftructed by the prejudice of authority, is in nothing so conspicuous as in the small-pox; which, though a disease almost universally incident to the human race, and treated by innuinerable writers from Rhazes down to the present time, yet remains, with regard both to its nature and method of cure, in a state of great imperfection. That the cool regimen is of much importance in this, as well as every other acute distemper, is a truth ascertained beyond all possibility of question; but it is not alone sufficient for suppressing the violence of those symptoms that occur in all the bad kinds of small-pox. Hence the continuance, if not really the increase, of mortality which still prevails remarkably in the natural species of the disease. From this confideration the author of the present treatise has been induced, for many years past, to pay particular attention to the worst kinds of small-pox; on which it must be acknowledged that his practical observations are transcendently judicious and valuable, at the same time that they are intimately connected with a theory which seems not to be more supported by just and ingenious reasoning than by fact and experience.

Dr. Walker begins with reciting the first accounts of the small-pox, and opinions concerning its origin. The most an.' cient writers on the disease are doubtless the Arabians; but whether it was a distemper indigenous amongst that people, is a point not positively determined. The learned Dr. Freind, as our author observes, suggests the idea that they had probably derived the infection from some of the more distant regions of the East; and indeed this opinion seems to receive confirmation from the account related by Mr. Holwell, who resided long in India, where the Bramins appear to have been acquainted with the disease from a very remote period. The Arabians, from whatever quarter they imported it, brought the disease at first into Egypt, and afterwards carried it, in the course of their conquests, into Europe. But the great epoch of its disseminas tion was the expedition of the crusades ; in consequence of which we learn, from John of Gaddeston, an English physician, that

the i the small-pox was common in Britain about the end of the twelfth century.

Thougn every reason justifies the inference that the remote cause of the small-pox is contagion, there are not wanting some writers who maintain it to be merely an inflammation, sui generis ;; observing, in support of this opinion, that the disease frequently invades soon after excess in eating, drinking, violent exercise, or change of air. But it is evident, from this remark, that they confound the remote with the occasional causes. We know that various abuses of the non-naturals will act in the capacity of the latter ; but we have no proof that any thing elfe than variolous particles, visible or invisible, can actually communicate the small-pox. Our author juftly observes, that, from the consideration of this contagion producing no pernicious effect upon those who are not susceptible of the disease, we cannot reasonably suppose it to be possessed of those virulent and deleterious qualities which have been ascribed to it by some physicians; and that, though inflammation be the first obvious effect of variolous matter introduced under the cuticle, there appears an evident difference between this and every other inflammatory affection. For, as neither simple inflammation, nor the highest degree of it, ever proves contagious, it would appear that variolous contagion must be endowed with a property distinct from every common inflammation, by which it is rendered contagious. . The consideration of variolous contagion being an animal production, and that a peculiar fætor constantly attends the disease, are circumftances which very justly induce our author to regard the inflammatory principle of the small-pox as porsefsing somewhat of a septic quality; and for this opinion respecting the nature of the variolous contagion, he adduces the following observations:

• Every species of small-pox we are acquainted with, or that have been described by authors, seems to point out the existence of the inflammatory-septic principle, from whence they originate. In the contiguous species, where the puftules are numerous, a considerable degree of inflammation attends every ftage of the disease; at the same time, the fætor is very confiderable, and the second fever is commonly of the putrid kind. In the confiuent and more malignant species, the eruptive fever, and other fynıptoms, indicate great inflammation, and the fætor constant and great. Beides, we frequently find, that this fever, sooner or later in the courie of the dif. ease assumes another type; a sudden proftration of it ength comes on; the interstices of the pustules are occupied with petechie, and followed with hemorrhages from the nose, lungs, uterus,&:c. and the fætor highly offensive. In every case of imali pox, therefore, we have evidence of the presence of this principle, the mildest

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