An ac

which this article embraces. count is given of the invention of the air pump, by Güricke of Magdeburg, about the middle of the seventeenth century, of his statical balance, and anemoscope: the introduction of experimental science into England, and the institution of the Royal Society are next related; this naturally leads to the mention of some of its most celebrated members, as Boyle and Hook, the latter of whom greatly improved the form of the air pump; next come the experiments of Huygens, who, from the suspension of mercury in a glass tube exhausted of air, was led to infer the existence of a more subtile fluid, which he called æther: the cistern barometer is then described; after which are detailed the various contrivances for enlarging the scale of the variations of the barometer ;--first in order is the barometer of Descartes; then the double barometer of Huygens, the advantages and disadvantages of which are pointed out; next, the more accurate double barometer, and the wheel barometer of Dr Hook; the inclined barometer, ascribed to Sir Samuel Moreland; the square barometer of Cassini and Bernoulli; the conical barometer of Amontons; the sectoral barometer proposed by Magellan; the adaptation of the differential scale for measuring minute divisions, first proposed by Vernier, early in the seventeenth century, but long afterwards strangely neglected;-the article next proceeds to mention the circumstances which influence the variations of the barometer, viz. the effect of moisture within the barometric tube, the effect of the width of the tube-the uniform convexity of the surface of pure mercury in properly constructed barometers, the quantity of depression in different tubes,-the application of a leather bag to the syphon barometer,-the effect of heat on the barometer, which leads to an account of the successive improvements of the thermometer; marine barometers are next described, the most approved kind of which, manufactured by Mr Cary of London, is illustrated by a figure, in a well executed plate the difficulty of explaining the variations of the barometer are adverted to, and some hints are thrown out relative to these causes.—On the whole, we think this a very able article, though, perhaps, a little too discursive. VOL. I.

As a sequel to the article BAROMETER, we have, from the same pen, a paper on BAROMETRICAL MEASUREMENTS. The decisive experiment by which Pascal ascertained that the pressure of the atmosphere diminished according to its elevation, naturally suggested to him the possibility of measuring by the barometer the relative heights of distant places on the surface of the globe. The first attempts, however, were rude, as they proceeded on the inaccurate supposition that the lower mass of air is a fluid of uniform density. We regret that our limits prevent us from accompanying Mr Leslie in tracing the successive steps by which the instruments and the rules employed in barometrical measurement have attained their present state of perfection. One interesting discovery, however, lately made by this mode of distant levelling, we must, in justice to our readers, mention. Two Prussian travellers, Engalhorde and Parrot, who proceeded, on the 13th July 1814, from the mouth of the Kuban, on the Black Sea, to the mouth of the Terek, on the Caspian, ascertained, by a series of fifty-one accurate observations, that the Caspian is 334 English feet below the level of the ocean; and that, at the distance of 189 miles from the Caspian, the country is depressed to the level of the occan-thus leaving an immense basin, from which the waters are supposed to have retired by a subterraneous percolation.

In the article BATHING, the medical and physical effects of the various kinds of baths, in various circumstances, as determined by the observations of Wright, Currie, Seguin, Parr, Haygarth, Fourcroy, Marcard, and other able physicians, are minutely and accurately detailed.

The article BEAUTY we opened with peculiar interest; and though we are very far from agreeing to the theory proposed, and the reasoning by which that theory is supported, we are ready to do full homage to the abilities displayed in the discussion. We cannot say, however, that we greatly admire the style in which the article is composed. It is distinguished, indeed, by great vigour of conception, and by a command of language almost peculiar to its celebrated author; but the vehemence of its tone, and the dogmatical confidence of its assertions, remind us 2 A

more of the manner of a pleader at the bar, anxious at all events to make good his cause, than of the calm and dispassionate style of a philosophical inquirer of which Mr Alison and Mr Stewart, in their treatises on the same subject, had given so pleasing specimens. We shall not at present attempt any analysis of the contents of this article, as we hope soon to have a communication on the subject from a correspondent.

Under the article BEE, the many curious and interesting facts relative to the physiology and economy of these remarkable insects, which have been discovered by the researches of Swammerdam, Maraldi, Reaumur, Schirach, and Huber, are detailed in a clear and systematic manner: but as these facts are now so generally known, we think it unnecessary to give any analysis of the article.

BEGGAR is the next subject that claims our attention. The information contained in this article is chiefly drawn from the report of a committee of the House of Commons, appointed, in 1815, to inquire into the state of mendicity in the metropolis. Beggars are classed into those who beg from necessity, and those who beg from choice. With regard to the relative numbers of these classes, the information of the committee was quite contradictory. Two of the witnesses examined, whose experience was equal or superior to that of all the rest taken together, asserted, that a proportion as large as one half were beggars from necessity, and some of them extremely worthy objects of compassion; while others asserted, that all beggars, with hardly any exception, were beggars from choice. One fact, extremely honourable to the working part of the community, seems to be well ascertained. Of the journeymen in the metropolis, no one is ever known to beg, though thousands of them, in the fluctuations of trade, have been reduced to the most cruel privations; and not a few of them actually starve, unpitied and unknown! The number of beggars in the metropolis the committee have been unable to ascertain; but it appears to be certain that it is gradually diminishing. Of the deceptions practised by beggars very erroneous notions have been entertained. In the number and variety of their contrivances they are supposed to exercise

wonderful ingenuity; whereas their expedients are few, obvious, and coarse. Of the methods proposed for suppressing begging, there seems to be none so deserving of approbation as the scheme of the society at Edinburgh for that laudable purpose. Nothing can be more judicious than the principles on which the society proceeds; and their exertions have met with the success to which they are so well entitled. It is objected to their plan, by the writer of this article, that it is not calculated for permanent or general use. Let their example be generally followed, and there can be little doubt that it will be found generally beneficial.

The article on BENEFIT SOCIETIES proceeds from the same pen, and is marked by the same prepossessions, as the article on Banks for Savings. It is unnecessary, therefore, to say any thing of it at present, as another opportunity will offer of examining the doctrines and the principles which it contains.

Besides the articles to which we have already adverted, this part of the Encyclopædia contains some good biographical sketches of Joel Barlow, Barry, Barthez, Basedow, Beattie, Beaumarchais, Beccaria, Beckmann, and Beddoes.

EDINBURGH ENCYCLOPEDIA, Vol.

XI. Part I.

Two different plans have been adopted by the Editors of Encyclopædias, which may be distinguished by the epithets of alphabetical and scientific. In the Cyclopædia edited by Dr Rees, there is indeed a vast treasure of valuable knowledge; but the plan of that work appears to us, in several respects, essentially faulty. One grand objection to it is its extent, which places it far out of the reach of ordinary readers; another objection, the consequence, indeed, of the former, is the enormous length of most of the articles, which, instead of being compendious treatises, are prolix and ill digested compilations, apparently intended to contain every thing that seems to bear, however remotely, on the subject; but a still more important objection is the want of unity, occasioned by dividing a subject into separate departments, which are discussed in different, and often distant, parts of the work. The Edinburgh Encyclopædia, on the other

hand, by a judicious plan of selection, reserves a due space for the discussion of important subjects, while it is overloaded with no useless and lumbersome matter. Its plan is sufficiently extensive to embrace every thing useful in history, literature, and science; but not so extensive, and herein lies its excellence, as to admit of the tedious and perplexing tautology, which is unavoidable when the same subject is brought under the view of the reader, in different articles, and in various forms. The respectable names which appear in the list of its contributors were, from the first, a pretty sure pledge of the ability with which it would be conducted; and the pledge has been fully redeemed. Many of its leading articles may be held forth as the best treatises which have appeared on their respective subjects; and the plan very properly adopted of having every article an original communication, marked by the signature of its author, has excited among the contributors a very beneficial emulation, and conferred on the work a uniformity of excellence of which none of its rivals can boast.

Our notice of the articles which this half volume contains must be extremely brief; and this we are the less disposed to regret, as there are not many of them which can be supposed to be very generally interesting. The first in order is HERPETOLOGY, the natural history of reptiles. Under the term reptiles, it is observed, naturalists have generally comprehended all those tribes of oviparous animals commonly called amphibia, including both oviparous quadrupeds and serpents; but in this article it is proposed to consider only the first order, reserving the history of the serpent tribes for the article OPHIOLOGY. The account which is given of these animals, and of the history of the science, is methodical, clear, and comprehensive; accompanied with a full list of references, which will be found very useful to those whose attention is directed to this department of zoology. The reptile tribes are distributed into three orders, Chelonians, Saurians, and Batracians. The first order comprehends turtles, of which there are six species, and tortoises, of which there are fifty-two species. The second order comprehends crocodiles, dragon, basilisk, tupinambis, guana, flying-dragon, agamas, stellios, cha

meleons, geckos, anoles, lizards, takydrome, scinks, efts, and chalcides. The third order comprehends the hylæ or tree frogs, rana or common frog, bufo or toad;-these constitute one family, called the batracians, without tails; the other family (or tailed batracians) consists of the salamander, proteus, and siren. In treating of the anatomy and physiology of these reptiles, the author gives a clear and comprehensive account of their motions, sensation, digestion, circulation and absorption, respiration and voice, secretion and excretion, integumation, generation, and hybernation.

HISTORY is the next article of im

portance. The plan proposed is, first, to point out and explain the various advantages of the study of history; secondly, to enumerate those branches of study which ought to be entered upon, previous to, or contemporary with, the study of history; thirdly, to give a brief and rapid sketch of the order in which ancient and modern histories may most conveniently and advantageously be read; fourthly, to point out the order in which the history of particular countries may be read, so that they may be illustrative of one another; fifthly, to notice the different species of history, besides what is emphatically called history. Notwithstanding some defects, this article may be perused with considerable advantage by those who wish to commence a regular course of historical reading.

The account of the province of HOLLAND is full of important and interesting information. Indeed the geographical articles of this Encyclopædia are distinguished in general by the extensive and accurate knowledge which they display, and by a happy discrimination, which rejects all extraneous matter, without omitting any thing that it is useful to know. The languishing state of manufactures and commerce in that once flourishing country, affords a striking exemplification of the vicissitudes of national prosperity. We have no room for details; but as a proof of the declining condition of the country, we may state, that, since the year 1732, the population of this province had, even previous to 1796, decreased by one thirteenth of the whole; that, except the internal trade with Germany, its commerce is almost annihilated; that many of its

principal manufactures have gone to decay; and that the only one which is on the increase, is the distillation of ardent spirits.

The article NEW HOLLAND Supplies the information, which the publication of Captain Flinders' discoveries has put us in possession of respecting this island, since the article Australasia was written. The author of these articles, however, seems to have known nothing of the journeys of Mr Evans and Governor Macquarrie into the interior-a deficiency which, we doubt not, the attention of the Editor will take the earliest opportunity of supplying. In other respects the article is valuable; containing an accurate and well-digested account of the coasts and bays, the mineralogy, botany, and zoology, of this immense island; of its inhabitants, their arts, manners, and

customs.

Our attention is next arrested by a very long article on HOROLOGY. We are told by the Editor, that he is indebted for this article to Mr Thomas Reid; and this may be regarded as a pretty sure pledge of its technical accuracy. On the whole, we consider it as the best account of horology that we have seen, so far as the practical part of it is concerned; and as many of the improvements on various branches of the art were invented by Mr Reid himself, no person, surely, could be better qualified to describe them. The departments of this curious art we shall merely mention, in the order in which they occur in Mr Reid's description. 1. The escapement, or 'scapement, that part of a clock or watch connected with their beats-on this part of the machinery Mr Reid has made several improvements; connected with the escapement is the remontoir, the intention of which is, that the movement passing through the wheels should, at intervals, be made either to wind up a small weight, or to bend up a delicate spring, which alone should give its force to the 'scapement; by which means the pendulum or balance was supposed to be always impelled by an equal and uniform force-Mr Reid has described a remontoir which he applied to the clock of St Andrew's Church in Edinburgh; 2. the compensation-balances, intended to counteract the effects of heat and cold on time-keepers; 3. balance or pendulum springs; 4. jewellery of

pivot-holes; 5. machinery for going in time of working, invented by Harrison-a contrivance of his own for this purpose is described by Mr Reid; 6. the dividing or cutting engine; 7. equation-clocks, an ingenious contrivance to show both mean and apparent time, invented in London about 120 years since; 8. repeating clocks and watches; 9. compensation-pendulums, two kinds of which have been invented by Mr Reid, the one with a zine tube and steel rods, the other with a glass tube; 10. wooden pendulumrods, on which Mr Reid made some experiments, which he details; 11. on the sympathy or mutual action of the penduluins of clocks; 12. on turretclocks; 13. on the method of fitting up astronomical clocks; 14. on chimes and bells.

To the amateurs of gardening, the article HORTICULTURE must prove an exquisite treat; while to the practical gardener it will afford much valuable instruction. It is evidently written by a person who not only understands the subject in all its practical details, but who has brought to that delightful study an elegant taste, and a philosophical mind. We cannot afford, at present, to give any analysis of so long an article, or even to mention the various topics which it comprehends. His own definition of HORTICULTURE, however, will give some idea of the principal branches into which the subject is divided. By the term horticulture," he observes, “is to be understood the whole management of a garden, whether intended for the production of fruit, of culinary vegetables, or of flowers. The formation of a garden may be included also, to a certain extent, under this subject: draining, enclosing, and the forming of screen plantations and hedges, may be considered as parts of horticulture, while the general situation of the fruit and the flower gardens, in regard to the mansion-house, and the position of some of their principal component parts, as shrubberies, hot-houses, parterres, and walks, belong more properly to landscape-gardening."

Thus we have adverted, in a very cursory manner, to the leading articles in this half-voluine. It contains, besides, several excellent articles in biography, geography, &c. On the whole, we think that this number supports well the credit of its predecessors.

A NEW instrument, called a Capillary Hydrometer, for measuring the strength and specific gravity of spirituous liquors, has lately been invented by Dr Brewster. The principle of the instrument is to determine the specific gravity from the number of drops contained in a small glass bulb, so that we have only to fill this bulb with any mixture of alcohol and water, and count the number of drops necessary to empty it. When a bulb about 1 inch in diameter was filled with water, it yielded only 724 drops, whereas, with ordinary proof spirits, it yielded 2117 drops, giving no fewer than a scale of 1393 drops for measuring specific gravities from 0.920 to 1.000. A correction must be made for temperature as in all other instruments.

A remarkable fossil has lately been discovered in the parish of Alfold, in the county of Surrey, some miles east of Guildford, It was found about eight feet under the surface in a bed of clay. Above the clay, in that particular part, is a bed of gravel, which extends to a considerable distance east and west, and varies in breadth from eleven yards to about forty, and has the appear ance of having been the bed of a river. The fossil consists of hard clay covered with thin rectangular scales, lying in a regular order, about of an inch long, and broad. These scales have been analyzed by Dr Thomson, and found to consist of Animal matter,

Phosphate of lime, Carbonate of lime, Loss,

11.37 65.51 19.65

3.47

100.00

This is nearly the composition of the scales of fishes as determined by Mr Hatchet.

A new mineral, consisting of sulphate of barytes and carbonate of strontian, has been lately discovered at Stromness, in the Orkney Islands, by Dr Thomas Traill of Liverpool. An account of the analysis of this mineral by Dr Traill was read at one of the late meetings of the Royal Society of Edinburgh. He proposes to call it barystrontianite from its composition, or stromnessite from its locality.N. B. We have seen specimens of this mineral, and conjecture that it is a compound of the two known species, carbonate of strontian and sulphate of barytes, and that with care the two minerals might be separated from each other.

A new artificial horizon has lately been invented by Mr White of Kinross, of which an account will be found among our Original Communications.

Mr W. K. Northall, of Wolverhampton, announces that he has discovered a new method of propelling boats by steam. The velocity of the boat may, by this plan, be

easily increased from three to seven miles an hour. The weight of the machinery will not be more than three tons, and the space it will occupy is comparatively small.

Mr J. B. Emmett of Hull has published some experiments which he made during the summer of last year, with the view of ascertaining whether a gas might not be obtained from oil, equal to that obtained from coal, so as to prevent the injury threatened to the Greenland trade by the rapidly increasing use of the latter in the lighting of towns, &c. By distilling various oils, previously mixed with dry sand or pulverized clay, at a temperature little below ignition, he obtained a gas which appeared to be a mixture of carburetted hydrogen and supercarburetted hydrogen gases. This gas pro duces a flame equally brilliant, and often much more brilliant than that produced from coal. It differed very little in quality, whether obtained from mere refuse, or from good whale sperm, almond or olive oil, or tallow. The gas, when burnt, produces no smoke, and exhales no smell or unpleasant vapour. Whatever oil is used, it evolves much more light when burnt as gas than when consumed as oil; in the latter case, the flame is obscured by a quantity of soot; in the former, the soot remains in the dis tilling vessel, and the flame burns with a clear light,

The water of the ebbing and flowing spring lately discovered in the harbour of Bridlington, Yorkshire, and described in the Philosophical Transactions for: 1815, by Dr Storer, has been found to possess many excellent properties, and been administered with decided benefit in numerous cases of chronic disease. It has been analyzed by Mr Hume of Long-Acre, who finds that great purity is one of its most distinguishing properties, in which it may vie with Malverne well; that although this stream is so nearly connected with the sea, which covers its whole vicinity twice a day, yet it is altogether free from muriate of soda, cvery kind of sulphate, and magnesia. It is little heavier than distilled water, and contains no other aëriform substance than carbonic acid. The solid contents of a wine gallon amount to 134 grains, consisting of-carbonate of lime, 3.750; silex, and a little oxide of iron, about .125.

The Rev. F. H. Wollaston has submitted to the Royal Society a description of a thermometer constructed by him, for determining the height of mountains, instead of the barometer. It is well known, that the temperature at which water boils diminishes as the height of the place increases at which the experiment is made; and this diminution was suggested, first by Fahrenheit, and afterwards by Mr Cavendish, as a mediu