on which the whole structure is founded. One of the most important of these additions is contained in the third section of the second chapter, giving an account of the proportions in which bodies combine, and of the atomic theory.' We have had occasion to refer to these doctrines in different articles, so that it will be unnecessary now to enter into any long or minute detail of them; and our present object will be to examine how far Dr. Henry has been successful in his manner of treating the subject, not to discuss the merits of the subject itself. On this point, we have no hesitation in pronounc ing our entire approbation of the author's labours; and we quote the subsequent paragraph as an example of his clear method of announcing Mr. Dalton's leading principle:

Though we appear, when we effect the chemical union of bodies, to operate on masses, yet it is consistent with the most rational view of the constitution of bodies to believe, that it is only between their ultimate particles, or atoms, that combination takes place. By the term atoms, it has been already stated, we are to understand the smallest parts of which bodies are composed. An atom, therefore, must be mechanically indivisible, and of course a fraction of an atom cannot exist. Whether the atoms of different bodies be of the same size, or of different sizes, we have no sufficient evidence. The probability is, that the atoms of different bodies are of unequal sizes; but it cannot be determined whether their sizes bear any regular proportion to their weights. We are equally ignorant of their shape; but it is probable, though not essential to the theory, that they are spherical. This, however, requires a little qualification. The atoms of all bodies probably consist of a solid corpuscle, forming a nucleus, and of an atmosphere of heat, by which that corpuscle is surrounded; for absolute contact is never supposed to take place between the atoms of bodies. The figure of a simple atom may readily, therefore, be conceived to be spherical. But in compound atoms, consisting of a single central atom, surrounded by other atoms of a different kind, it is obvious that the figure (contemplating the solid corpuscles only) cannot be spherical; yet if we include the atmosphere of heat, the figure of a compound atom may be spherical, or some shápe approaching to a sphere.'

Dr. Henry then proceeds to explain the manner in which Mr. Dalton has attempted to ascertain the weights of the ultimate atoms of bodies; commencing with what he calls the binary compounds; i. e. when the compound consists of two elements only, and when, by actual experiment, we discover in what proportion the two elements combine, which, supposing single particles of each to unite together, indicates the proportional weight of the atoms themselves. By ascertaining the relative quantity in which two elements unite, and comparing these with a third elementary combination, we ob

tain a new series of numbers, from which we are led to others still more complicated; so that, if we admit the truth of the data, we have it in our power to discover the proportional weight of the atoms which constitute the most compounded bodies. Thus, beginning with the composition of water, we learn the weight of the atoms of oxygen and hydrogen, while from that of ammonia we learn the weight of the atom of nitrogen; and from these three elements, taken as a basis, the calculations may be extended to the weight of the atoms of all substances, the composition of which can be accurately detected. It is obvious, however, that these numbers can be only proportional; and that any scale of actual quantities must be founded on an arbitrary determination, some one being assumed as the standard to which all the rest are to be referred. In the formation of this scale, different experimentalists have employed different terms of comparison; Mr. Dalton having fixed upon hydrogen, while Wollaston, Thomson, and Berzelius, have assumed oxygen as the decimal unit.

This doctrine, however, respecting the weight of atoms, although extremely curious, and derived from a very ingenious train of reasoning, must be regarded as altogether hypothetical; and principally valuable as tending to establish the doctrine of definite proportions, or equivalents: a doctrine which may be considered as of the utmost moment both to the theory and the practice of chemistry, and as tending to produce, on each of these points, a degree of certainty which probably could not be obtained by any other mode of investigation. The following is a clear and simple exposition of the foundation on which this important doctrine rests:

Now it is remarkable, that when one body enters into combination with another, in several different proportions, the numbers indicating the greater proportions are exact simple multiples of that denoting the smallest proportion. In other words, if the smallest proportion in which B combines with A, be denoted by 10, A may combine with twice 10 of B, or with three times 10, and so on; but with no intermediate quantities. There cannot be a more striking instance of this law than that above mentioned, of the compounds of manganese with oxygen; in which the oxygen of the three last compounds may be observed to be a multiplication of that of the first (14) by the numbers 2, 3, and 4. Examples, indeed, of this kind have, of late, so much accumu lated, that the law of simple multiples bids fair to become universal, with respect at least to chemical compounds, the proportions of which are definite.'

In the next section, on Elective Affinity,' we have a perspicuous view of the hypothesis that was originally proposed by Bergmann; with the objections that were offered against

it by Berthollet, and the still later objections made to his opinions. On these points we have some important additions, especially with regard to the doctrine of definite proportions as applied to this subject, concerning which Dr. H. makes these remarks:

The theory of Berthollet, however, which promised, on its first development, to form a new era in chemical philosophy, has lost much of its probability, by the subsequent progress of the science. It is directly, indeed, at variance with the doctrine of definite proportions, which every day gathers strength by the accumulation of new and well established facts. It is liable, moreover, to the following objections.

These objections are then clearly stated, and the author thus concludes:

Notwithstanding these objections to the theory of Berthollet, when carried so far as has been done by its author, in the expla nation of chemical phenomena, it must still be admitted that the extraneous forces, pointed out by that acute philosopher, have great influence in modifying the effects of chemical affinity. But these forces are entitled only to be considered as secondary causes; and not as determining combinations or decompositions, nor as regulating the proportions in which bodies unite, independently of the superior force of chemical affinity.'

We have given a detail of these two sections, in their present amplified form, because the alterations and additions which they have received are perhaps the most considerable of any in the volumes; the new matter consisting, for the most part, not in the introduction of fundamental principles or doctrines, but simply of individual facts. These are much too numerous for us to attempt to particularize them; and we shall therefore content ourselves with remarking that Dr. Henry has diligently sought for information from all quarters, has incorporated it into his work so as to maintain the unity of the design, and has in short presented the public with a correct view of the actual state of the science at the present period. He does not profess to enter into all the details which occur in the systems of Thomson and Murray: but, after having examined different parts of his volumes, we must say that we have been surprized to find how much valuable matter the author has contrived to include within a comparatively small space.

ART.

ART. V. Cursory Remarks on the Physical and Moral History of the Human Species, and its Connections with surrounding Agency. By L. S. Boyne. 8vo. pp. 378. 10s. 6d. Boards. Baldwin and Co.

THE

HE object of this volume, as expressed in the title, is of the first interest and importance; and its complete developement would require a very comprehensive mind, and one that was well stored with information of various sorts. Perhaps, even, it would not demand less ability to give a rapid and condensed view of the subject than a more minute and elaborate detail; since an equally extensive range of knowlege would be requisite, and an equally philosophical turn of mind in proportioning the different parts to each other, and observing their respective relations and connections. How far Mr. Boyne is qualified for the arduous task, either by his natural talents or his acquirements, it now remains for us to ascertain.

His work is written in the form of letters, but it does not appear that the correspondent has any pretensions to an actual existence, or that any particular object is gained by this mode of arranging the materials. We do not observe any characteristic marks of the epistolary style, nor that Mr. B. has conceived any thing in the situation of his imaginary friend which can add either to the interest of the performance or to the facility of conveying his sentiments. The author's inquiries, however, take a very extensive scope. He commences with some remarks on the solar system, the theory of the earth, its figure, the state of its surface, and other similar topics; and he then proceeds to the consideration of the different material agents which affect the terrestrial globe, and the elements which compose it. An account of air, fire, oxygen, nitrogen, carbon, the atmosphere, winds, &c. forms the subject of the second letter; and in the third we have light, vision, colour, matter, space, vacuum, attraction, time, magnetism, and materialism. Our readers will agree with us in thinking that the arrangement is not the most natural and philosophical which might have been adopted; and throughout the whole volume the different topics are introduced without much apparent order or connection, but rather as they appear to have sprung up in the mind by some accidental or casual

association.

In the fourth, fifth, and sixth letters, Mr. Boyne enters into a review of organized bodies, with the laws and functions of vegetables, and the transition from vegetables to animals: then commencing with insects, he proceeds to fish, amphibia, birds, and quadrupeds. In the next six letters, we have an

abstract

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abstract of the principal facts connected with the physical history of the human species; beginning with the corporeal structure, then passing to the physiology, and afterward considering the diversity that prevails among individuals, originating both from external and internal causes, with the relation which they bear to each other. Two letters are then devoted to the human mind; and lastly occur three of a more miscellaneous nature, referring to some of those leading events that have happened in the history of mankind, and which have tended to produce very important effects on the human race, either individually or generally: such as the invention of writing and printing, the introduction of Christianity, and the extension of commerce.

When we reflect that all these topics are discussed in the space of a single volume, of moderate size, it must necessarily follow that they can be treated only in a very cursory manner; and we shall perhaps be disposed to object fundamentally to the nature of a work which undertakes to effect so much in so small a compass. Waiving, however, this kind of general remark, and admitting the author to choose his own plan of proceeding, let us take a more particular review of certain parts of his performance, in order to enable us to judge how far he has succeeded on his own principles. We shall quote a few passages, as we turn over the pages, without exercising any particular selection. After an account of the common properties of matter, Mr. Boyne contrasts them with 'the living attributes of organized substances,' which latter he assumes as being something essentially different from the former. following are his remarks on this topic; and it is scarcely necessary for us to observe that they are entirely commonplace, and derived from the most general and cursory view of it:

A

The

All the properties enumerated as attached to matter in ge neral, we find perfectly passive; it is incapable of itself of taking on any degree of action; it possesses only the aptitude of being acted on by other agency, without any power of resisting the force of that agency; it is entirely inert, and remains for ever in the same state of quiescence, when not exposed to the active energies of other powers. The dormant and inactive state in which we observe matter to have remained for ages, would seem sufficient to refute the notion of its possessing properties of an active nature, capable of taking on the form and texture of organic existence. Many philosophers, however, with the talents of Priestley at their head, have supposed in matter a capacity of assuming active energy, and changing itself into modes of organized substance. We find so striking and important a difference between the properties of living and dead matter, that we are at

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a loss