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regret that we must begin with reprehension. Too much space is employed in recapitulating Mr. Kirwan's early arguments in opposition to Lavoisier's system---a system which the former has now adopted---and the modern doctrine engages too little of our author's attention. This is not rectified in the supplement; but we shall resume the subject under the article of chemistry.'
The first distinct treatise is on 'acoustics.' It is popular, rather than elementary, and confined to the vibrations of stringed instruments. Yet perhaps the whole doctrine should have been brought together; and we are left in uncertainty where it is resumed. We must thus early mention a striking error, viz. that the articles have neither references to the other portions of the work annexed, nor to authors who have treated more fully of the different subjects. Under the head of • acids,' for instance, there is no reference to the article • chemistry ;' and no enumeration of the different kinds of acids, to lead us to look for the properties of cach under their separate titles. • The mechanical properties of air' are well explained; but, when the authors treat of the chemical, they are too much immersed in the old school, and scarcely dare to venture beyond the leading-strings of Dr. Priestley. The old nomenclature is also retained, with all its imperfections; and even phlogiston is not wholly resigned, or resigned unwillingly. In consequence, perhaps, of the period at which this article was composed, the number of known aërial fluids is very incomplete. The heavy inflammable gas, the nitrous oxyd, the hydrocarbonat, &c. are omitted.
• Aërostation' is detailed at some length. Of algebra,' the elements only are given; and, in a work of this kind, we can expect no more: they are explained with great neatness and sufficient precision. The article of ' alkalis' is instructive; but the author has not been sufficiently explicit in his account of the principles of the volatile alkali, from not consulting the latest authors. We thought that there was much ingenuity displayed in the distinction of 'animal' and vegetable substances. Many of the remarks are also new; and, were we not afraid of extending our account of this work too far, we should have copied some of the observations. The articles on archery,'animalcules,' and ` annealing,' are, we think, good; and the treatises on 'anatomy' and architecture' contain a scientific and sufficiently complete view of their respective subjects. The treatise on " arithmetic' is full and satisfactory; that on "astronomy' very comprehensive; but we look in vain for Dr. Herschel's late labours, which were at least in time for the supplement. The account of ' comets' might have been improved from M. Pingrè's very systematic work; and the appearance of the tails, as connected with the Aurora borealis, and the latter as occur. ring exclusively in the magnetic meridian, would, if brought together, have elucidated this difficult inquiry. The 'stars' dim twinkling' through the light of the Aurora are not suffi. ciently noticed. The properties of the atmosphere are well detailed; but they should have been included under air' or
aërology ;' or at least a reference should have been inserted, to inform the inquirer where these are to be found. As there are no regular references, an index should have been subjoined: it may not yet be too late.
In the former part of the second letter of the alphabet, there are few treatises; but the articles are often extensive and valuable. We can notice only the following. --- Banks' and • banking' are explained at some length. Baptism,' and the various opinions on the subject, are explained also with great propriety. We mention this the more readily, to remark that the articles on religious subjects are, in general, executed with judgement, and display considerable knowledge, as well as a rational piety, without an improper attachment to any particular sect. What is said of horses occurs under the article • barbs,' where it would be least expected; and it would appear still more unlikely to find an account of the ass, the zebra, the hemionus of Pallas, and the mule, under this article,
The account of the horse, however, is clear, and on the whole exact. The article of .bards' is incomplete, and somewhat erroneous: they are improperly confounded with the druids. The bark,' and its uses in the economy of vegetation, are described chiefly from authors of a former date; and the more modern philosophers are in a great degree overlooked. What relates to the · Peruvian bark' appears to be full and correct. The article of barometer' is also satisfactory; but, with respect to the cause of the mercury sinking on rain, and rising on the return of dry weather, the authors feel a difficulty which has perplexed all their predecessors, merely from not reflecting that the barometer is not so much a standard indicative of the absolute weight of the air, as of its elasticity. What relates to the mode of measuring heights by this instrument is too short, and inconclusive. On the subject of "basaltes' and its origin, the opposite opinions are detailed at some length, without any conclusion. The later authors, and the now general opinion that their form is the consequence of retraction from solution, and not from fusion, are omitted. The lizards, or rather the species of lacerta, including the crocodile, occur under the term basilicus,' one of its species; a very material error in arrangement, which pervades the whole work.
The following articles in this letter appear to be ably exe. cuted; and several of them, as well as our recollection assists us, seem not to have made a part of any former English dictionary. This is particularly the case with “bird-catching,' which is a curious and entertaining subject. Under the titles of “beaver’and
bee,' we have too much of the common fancy of extraordinary sagacity, directed to an end which requires wisdom to discover, and reasoning to pursue. Later observation has destroyed many of these final causes; and the whole of these contrivances do not reach beyond the powers of instinct in other animals. The hexagonal form of the cells of the honeycomb, for instance, has been extolled as a masterpiece of contrivance, because it contains the greatest space with the least quantity of materials. The observers are not aware that every viscid fuid extended on a plane surface retracts in a similar form in drying. The biographical accounts are more numerous, more judicious, and comprehensive, than in many other dictionaries. We have sometimes thought that they were not sufficiently full; but we greatly distrust any judgement of this kind formed from a partial view, as it is difficult to adjust the proportion of attention which any subject may demand in so extensive a work. The article of blindness' is certainly too long: much space is filled with declamation; and the degree of improvement, of which the other senses are capable, seems not to be clearly understood. Dr. Moyes, in his youth, made a watch; but, what is more surprising, he made previously the tools. His compasses were only the tongue of an old buckle bent to the proper distance. There is not any evidence of the blind distinguishing colours. We knew a dyer who attempted it, and often succeeded; but we found that he was assisted by the smell. A blind man, with all his acuteness of hearing, cannot always say on which hand a distant sound is approaching. Yet, from the tone of his voice, often from his sense of feeling, he will say whether a room be large or small, low or high: when he looks out at a window, he will be able to determine whether the prospect be confined or extensive, whether it face the street or the country. The same sagacity of feeling was observed in a blinded båt by Ju. rine,
Under the article · blood,' we find a very enlarged account of this general fluid of the system, which the author thinks is the immediate reservoir of the vital principle. We wish not to extend our article very far; but, as this principle of the Hunterian school is here more fully drawn out, and more ably supported, than in any other modern system, we shall select the passage. We may perhaps be pardoned, as, in a work of this kind, novelty is not generally expected, and not often found.
• To follow this dispute through every argument that hath been
or that may be used by both parties, would prove tedious, and to us appears in a great measure unnecessary, as the following short considerations seem to decide the matter absolutely against the patrons of the nervous system. In the first place, then, if we can prove the life of the human body to have existed in, or to have been communicated from a fluid to the nervous system, the analogical argument will be very strongly in favour of the supposition that the case is so still. Now, that the case once was so, is most evident; for the human body, as well as the body of every other living creature, in its first state, is well known to be a gelatinous mass, without muscles, nerves, or blood-vessels. Nevertheless, this gelatinous matter, even at that time, contained the nervous fluid. Of this there can be no doubt, because the nerves were formed out of it, and had their power originally from it; and what is remarkable, the brain is observed to be that part of the animal which is first formed. Of this gelatinous fluid we can give no other account, than that it was the nutritious matter from which the whole body appears to be formed. At the original formation of man, and other animals, therefore, the nutritious matter was the substratum of the whole body, consisting of muscles, nerves, blood-vessels, &c. nay more, it was the immediate efficient cause of the nervous power itself. Why should it not be so now as well as then? Again, in the formation of the embryo, we see a vital principle existing as it were at large, and forming to itself a kind of regulator to its own motions, or a habitation in which it chooses to reside, rather than to act at random in the fluid. This habitation, or regulator, was undoubtedly the nervous system, and continues so to this moment; but at the same time, it is no less evident that a nutritious fuid was the immediate origin of these same nerves, and of that very nervous fluid. Now we know, that the fluid which in the womb nourishes the bodies of all embryo animals, is necessarily equivalent to the blood which nourishes the bodies of adult ones; and consequently, as soon as the blood became the only nutritious juice of the body, at that same time the vital or nervous fluid took up its residence there, and from the blood diffused itself along the nerves, where it was regulated exactly according to the model originally formed in the embryo. Perhaps it may be said, that the vital power, when once it hath taken possession of the human or any other body, requires no addition or supply, but continues there in the same quan. tity from first to last. If we suppose the nervous power to be ima material, this will indeed be the case, and there is an end of reason. ing upon the subject; but if we call this power a volatile and elas. tic Auid, it is plain that there will be more occasion for recruits to such a power than to any other fluid of the body, as its volatility and elasticity will promote its escape in great quantities through every part of the body. It may also be objected, that it is absurd to suppose any Auid, or mechanical cause, capable of putting matter in such a form as to direct its own motions in a particular way : but even of this we have a positive proof in the case of the electric fluid. For if any quantity of this matter has a tendency to go from one place to another where it meets with difficulty', through the air · for instance, it will throw small conducting substances before it, in
order to facilitate its progress. Also, if a number of small and light conducting substances are laid between two metallic bodies, so as to form a circle, for example ; a shock of electricity will destroy that circle, and place the small conducting substances nearer to a straight line between the two metals, as if the fluid knew there was a shorter passage, and resolved to take that, if it should have occasion to return. Lastly, it is universally allowed, that the brain is a secretory organ, made up of an infinite number of small glands, which have no other excretories than the medullary fibres and nerves. As a considerable quantity of blood is carried to the brain, and the minute arteries end in these small glands, it follows, that the fluid, whatever it is, must come from the blood. Now, there is no gland whatever, in the human, or any other body, but will discharge the fluid it is appointed to secrete, in very considerable quantity, if its excretory is cut. Upon the cutting of a nerve, therefore, the fluid secreted by the brain ought to be discharged; but no such discharge is visible. A small quantity of glairy matter is indeed discharged from the large nerves; but this can be no other than the nutritious juice necessary for their support. This makes it plain, even to demonstration, that the fluid secreted in the brain is invisible in its nature; and as we know the nervous fluid hath its residence in the brain, it is very probable, to use no stronger expression, that it is the peculiar province of the brain to secrete this fiuid from the blood, and consequently that the blood originally contains the vital principle. Vol. i. p. 797.
We cannot now enlarge on this subject; but we think the author mistaken; and may take another opportunity to point out the error and its source.
The only treatise in this volume that we have not noticed is on bleaching. The operation, as formerly conducted, is well explained; but our author stops short at the introduction of dephlogisticated muriatic acid, and its proposed use. It is now generally employed; and various refinements in this process have been introduced. Mr. Higgins's economical improvement, in substituting sulphuret of lime, is a very valuable one.
The plates bound with the first volume, though all do not belong to it, are fifty-six in number. The execution is greatly superior to those of any preceding dictionary, and the objects, in general, well chosen. To some we must, however, object, particularly to the view of Noah's ark, a representation in every respect puerile and uninteresting. We shall resume the work at a future opportunity ; and, having now introduced its general character, with instances of its principal faults and merits, our subsequent progress will be more rapid.