Imágenes de páginas
PDF
EPUB

but who is to execute his plan? We have no hopes from the yearly emigration of British travellers; their pursuits are of a different kind; and were they willing to undertake, we are afraid that very few of them indeed would be found able to perform the talk. Could the different governments in Europe be induced to fend out travelers capable of realising the ideas of the author, and were their reports from time to time made the basis of laws and regulations for the improvement of the national system, the consequences would be highly salutary to society. But nations, like individuals, are too often careless of their best concerns. For reasons of this kind we are afraid that the work before us will not be productive of all those advantages which it is certainly calculated to promote.

The second volume contains a catalogue of travels, and of books relative to that subject, arranged in such a manner that the reader may at once find the town or country concerning which he wishes for information.

Would the sensible and laborious author of this publication condense his work, we mean, would he give the essentials of it in a smaller form, we doubt not of its being more universally useful, because it would then have a better chance of being used as a travelling vade mecum.

Art. XI. Philosophical Transactions of the Royal Society of

London, Vol. LXXVII. For the Year 1787. Part II. 4to. 8s. 6d. fewed. Davis. London, 1787.

of the First Part of this volume we gave an account in our

y last Review; we now proceed to the Second Part, which begins with · Article XXI. An Experiinent to determine the Effect of extirpating one Ovarium upon the Number of young produced. By John Hunter, Esq. F.R.S. In this experiment the spayed fow neither bred so long, nor brought so many pigs, in an equa number of farrows, as the perfect one. In the first eight litters the number produced by the former was seventy-fix, and that by the latter eighty-seven. The fpayed animal farrowed no more; but the perfect one, in eight additional farrows, brought seventy-fix pigs. Mr. Hunter thence thinks it probable that the ovaria are from the beginning destined to produce a fixed number, beyond which they cannot go, though circumstances may tend to diminish that number; and that the constitution has no power of giving to one ovarium' the capacity of propagating equal to two. A single experiment may indeed not be decisive of these facts; but the great expence with which every repetition

of

[ocr errors]
[ocr errors]

of it must be attended, is sufficient to discourage the most zealous inquirer from prosecuting the subject any farther. • Art. XXII. Experiments made to determine the positive and relative Quantities of Moisture absorbed from the Atmo. sphere by various Substances, under similar Circumstances. By Sir Benjamin Thompson, Knt. F.R.S. The substances used in these experiments were sheep's wool, beaver's fur, the fur of a Russian hare, eider down, silk, linen, and cotton wool. It was found that the first of these absorbed the greatest quantity of moisture, and that the abforbing power of the others diminished progressively in the order in which we have stated them. Sir, Benjamin Thompson very justly ascribes to a difference in the absorbing power of these several substances the different effects . which they produce when worn next the skin. One of them feels warm because the moisture is immediately absorbed; and another cold and moist, from its greater resistance to the admission of the perspirable Auid. On the same principle, rather than its warmth, depends the power of woollen in promoting perspiration. · Art. XXIII. The Principles and Illustration of an advantageous Method of arranging the Differences of Logarithms on Lines graduated for the Purpose of Computation. By Mr. William Nicholson. This paper contains a series of computation, and of descriptions illustrated by diagrams. The scale is a circular one, compounded of Gunter's scale of a sector; an improvement equally suited to utility and convenience. · Art. XXIV. Observations tending to thew that the Wolf, Jackal, and Dog, are all of the fame Species. By John Hunter, Esq. F.R.S. Mr. Hunter has collected several instances to prove that the wolf and the dog breed together, and that their progeny is prolific; but the inferences that they are really of the same species, seem not to be quite satisfactory. The probability only is that they are of a similar kind. The instances are taken from confined animals; and with the final cause assigned, it can be of no weight in the argument, as the copulation of those animals is not likely ever to take place in a state of nature.

Art. XXV. Experiments on the Congelation of the Vitriolic Acid. By James Keir, Esq. F.R.S. It appears from these experiments, that the medium density of the acids which did freeze with the cold of melting snow was 1980; and that, at the densities of 1790 and 1770, the acid had been incapable of freezing with that degree of cold. It farther appears, that by applying a more intense cold, namely, that produced by a mixture of snow, salt, and water, the limits of the density of the acids capable of congelation were extended to about s'above or below the point of easiest freezing. There seems little reason to N 3

doubt

[merged small][ocr errors][ocr errors][ocr errors][ocr errors][ocr errors]

doubt that, by greater augmentations of cold, these limits may be farther extended; but in what ratio these augmentations and extensions proceed, cannot be determined without many obfervations made in different temperatures.

Art. XXVI. An Account of some Experiments on the Production of artificial Cold. By Thomas Beddoes, M.D. The experiments which are the subject of this paper had been made by Mr. Walker, apothecary to the Radcliffe Infirmary. He found that by adding successively fal ammoniac, nitre, and Glauber's salts, while they held the water of crystallisation to water, the thermometer sunk to forty-six degrees. When materials, previously cooled, were employed, the diminution of heat was more considerable ; and by adding such materials to cooled diluted spirit of wine, the thermometer funk to four. Experiments were likewise made with some other substances for the same purpose, and the results of them are mentioned. - Art. XXVII. An Account of a Doubler of Electricity; or a Machine by which the least conceiveable Quantity of positive or negative Électricity may be continually doubled, till it becomés perceptible by common Electrometers, or visible in Sparks. By the Rev. Abraham Bennet, A. M. The author of this article suggests an ingenious method of rendering small quantities of electrical Auid, in the air, perceptible to the fenses; and he has added to the method a journal of the electrical state of the air from the 23d of January 1787 to the 2d of March. In general the electricity was positive, except in rain; it was then universally negative, unless the rain had owed its origin to the accumulation of water in mifts; a cause very different from that which produces rain in the usual form. The negative electricity seems to be connected with foutherly winds, because these are con- . nected with rain; for it was found that when rain occurred, with: the wind even from the north-west and the west, the electricity was still negative. We wish to see these observations attentively profecuted. "

Art. XXVIII. Some Particulars relative to the Production of 1. Borax. By William Blane, Esq. This faline substance is brought

from Jumlate, a kingdom in the mountains of Thibet. The place where it is produced is described to be in a small valley, furrounded with snowy mountains, in which is a lake, about fix miles in circumference, the water of which, from hot springs by which it is supplied, is constantly hot, so much so that the hand cannot be held in it for any time. The earth round the lake is full of a saline matter, in such plenty that, after falls of rain or fnow, it concretes in white flakes upon the surface, like the natron in Hindoftan. : Upon the banks of this lake, in the winter, when the falls of snow begin, the earth is formed into small reservoirs,

!

by.

by raising it into ridges about fix inches high. When these are filled with snow, the hot water from the lake is thrown upon it, which, with the water from the melted snow, remains in the refervoir, to be partly absorbed by the earth, and partly evaporated by the sun. After this, there is found at the bottom a cake of crude borax, which is taken up and afterwards refined by boiling and crystallisation.

Art. XXIX. A Letter from the Father Prefect of the Mission in Thibet, F. Joseph da Rovato, containing some Observations relative to Borax. The account in this article agrees with that in the preceding, in describing borax as a natural, not an artificial production ; but the Father Prefect tells us that the fub. Atance is procured from rain. It is probable that the hot springs mentioned in the former narrative, dissolve the borax in large quantities; and the snow may be necessary to cool the water, in order that the salt may crystallise; while, in the second account, if by rain-water is understood the rain collected in falling from the neighbouring hills, the evaporation by the sun is sufficient to exhale the superfluous Auid.

Art. XXX. Sur les Gas Hepatiques. Par Monf. Hassenfratz. 'On Hepatic Air. By M. Hassenfratz. Mr. Kirwan had before given it as his opinion that hepatic air was only fulphur in än aerial state; but M. Haslenfratz has been able to hepatise many different kinds of air, and maintains that hepatic gas is only sulphurated air of different kinds. He sulphurated nitrous air; atmospherical mephitis, vital, and atmospherical air.

Art. XXXI. Botanical Description of the Benjamin Tree of Sumatra. By Jonas Dryander, M. A. This tree has been often mistaken by botanists. By Ray it was supposed to be a Virginian plant; while others confounded it with the croton, the mantissa, the terminalia, the laurus, &c. It is now ascertained, however, from a dried specimen, to be a species of styrax.

Art. XXXII. An Account of an Experiment on Heat. By George Fordyce, M. D. F. R.S. This experiment relates to the communication of heat, but leads to nothing new on the subject.

Art. XXXIII. An Account of an Observation of the Right Ascension and Declination of Mercury out of the Meridian, near his greatest Elongation, September 1786. By Mr. John Smeaton, F.R.S.

Art. XXXIV. A remarkable Case of numerous Births, with Observations. By Maxwell Garthshore, M.D.F.R.S. and A.S. This case is well authenticated, beyond the evidence usually accompanying similar narratives. The birth consisted of five infants, all females. Two of them were born alive, and the whole number within fifty minutes. The mother had before been : : : N4

delivered

[ocr errors][merged small][ocr errors]

delivered of a single child; and the husband, who had been in an infirm state for fome years, was, at the time of this incident, dying in a confirmed consumption. Dr. Garthshore gives a fhort account of other numerous births in Great Britain; and specifies the proportion in which they are observed to happen in different countries,

Art. XXXV. Chloranthus, a new Genus of Plants, described by Olof Swartz, M.D. This new genus is a Chinese plant, neither beautiful nor useful, and may be arranged in the fortyeighth natural order, next to the viscum. The name given it is inconfpicuus,' from the smallness of the flower.

Art. XXXVI. On the Precession of the Equinoxes. By the Rev. Samuel Vince, M. A. F.R.S. The precession is cal culated to be 21" 6" in a year; but as in the inquiry the earth is supposed to be of an uniform denfity, and the proportion of the equatorial and polar diameters to be fixed, the calculation must probably deviate a little from the truth.

Art. XXXVII. Abstract of a Register, of the Barometer, Thermometer, and Rain, at Lynden, in Rutland, in 1786. By Thomas Barker, Esq. Also of the Rain at South Lambeth, in Surrey; and at Selbourn and Fyfield, Hampshire. The variaţion of the thermometer was from 801 to in, which is greater than commonly happens. The barometer varied from 30.05 inches to 29.01. The rain at Lynden this year was 27.289 inches; at South Lambeth 22.43 ; at Selbourn 39.57; and at Fykeld 29.60 : 29.72 on an average. · Art. XXXVIII. Observations on the Structure and Economy of Whales. By John Hunter, Esq. F.R.S. The species here examined are the delphinus phocæna, or porpoise; the grampus; the delphinus delphis, or bottle-nosed whale; the balæio rostrata; the balælan mysticetus, or the whale-bone whale; the physeter macrocephalus, or the spermaceti whale; and the monodon monoceros, or the nar whale. In general, the tail of these animals is flattened horizontally, to enable them to rise, in order to breathe ; the flesh is very red, and of greater specific gravity than beef, so that the large quantities of fat are a necessary part of economy in these various species. What is çalled fpermaceti is found every where in the body in small quantity, mixed with the common fat of the animal, bearing a very small proportion to the other fat. In the head it is the reverse; for there the quantity of spermaceti is large when compared to that of the oil, though they are mixed together as in other parts of the body. The following remarks are particularly worthy of being extracted :

? Although this tribe cannot be said to ruminate, yet in the num. ber of ftomachs they come nearest to that order; bút here I suspect

thag

« AnteriorContinuar »