the nerves of the human body, and compare them with those of other animals, a very singular coincidence is observed between the number of organs, the compound nature of their functions, and the number of nerves which are transmitted to them. No organ which possesses only one property, or endowment, has more than one nerve, however exquisite the sense or action may be; but if two nerves coming from different sources, are directed to one part, this is the sign of a double function performed by it. If a part or organ, have many distinct nerves, we may be certain that instead of having a mere accumulation of nervous power, it possesses distinct

powers, or enters into different combinations, in proportion to the number of its nerves. The knowledge of this circumstance gives new interest to the investigation of this part of anatomy."

"Thus in reviewing the comparative anatomy of the nerves of the mouth, we shall find that in creatures which do not breathe, the mouth having only one function to perform, one nerve is sufficient. In certain animals, where the face and nostrils have no complexity of relations, these parts have only a single nerve. If the throat has no complexity of organization, it has no variety of nerves. But on the other hand, when the anatomist employs weeks to dissect and disentangle the nerves of the tongue, throat, and palate in the human subject, he finds at length, that he has exhibited the branches of five different trunks of nerves: and there is no clue to the labyrinth, until he considers the multiplied offices of the mouth in man that it is a pneumatic, as well as a manducatory organ: that it is the organ of voice and speech, as of taste, and exquisite feeling. It would, indeed, be matter of surprize, if the same nerve served for the action of gnawing and feeding in the lower animals of simple structure, and also for the governance of those complicated operations, which serve to interpret the wants and sentiments

of man."

In these terms our author developes the leading principle of his researches. He finds in all animals two systems of nerves; some of the differences between which have long been remarked by physiologists; but he points out the exact accordance of those systems of nerves superadded to the one simple symmetrical system which pervades all animals, with the complexity of functions superadded to the simple functions of sensation and loco-motion, and which increases with the rank of the animal in the scale of existence.

These luminous and profound views are established by a number of experiments and observations, the details of many of which are given in this paper. The function of respiration is selected as a good instance for the critical examination of the soundness of the principle proposed: and the arrangement of the systems of nerves in the different parts connected with this important function, are shewn to afford the strongest evidence in favor of the proposed theory.

Comparative anatomy, the author considers, as affording strong proofs of the truth of his principle. Among other instances, he states, that when a feeler or antenna answers merely the purpose of sensation, it has only one nerve running along it. It was suggested to him that if his theory were true, the trunk of the elephant, answering purposes both of feeling and respiration should have two nerves; whereas, Cavier has stated, that it has only one. Mr. Herbert Mayo however, in dissecting a young elephant, found the trunk furnished with two nerves proceeding from different systems, exactly as the theory supposes. In conclusion, Mr. Bell points out some practical applications of the knowledge thus attained, in surgery: he also promises a continuation of the investigation, with respect to the nervous systems of other parts of the body employed in respiration which will be necessary to complete the proof of his theory, he having in the present paper only gone through the nerves of the head and face.

We will now proceed to survey very briefly, the papers in the department of chemistry, in the volume before us.

No. 4. On two new compounds of Chlorine and Carbon, and on a new compound of Iodine, Carbon, and Hydrogen. By Mr. Faraday chemical assistant at the Royal Institution.

The true nature of chlorine which for a long time remained doubtful, having been ascertained, it became impor tant to learn the nature of all the compounds it was capable of forming. This has been long done with all except carbon: the author of the present paper has succeeded in forming two compounds of chlorine with this substance. These are found to be a per-chloride, and a proto-chloride of carbon. And their properties are examined at great length, and the modes of procuring them. The close analogy also between chlorine and iodine, suggested to Mr. F. the trial of forming a compound of the latter with carbon. He has as yet however only succeeded in uniting iodine with carbon by the intervention of hydrogen. The pure iodine remains for future research.

No. 27. On a new compound of Chlorine and Carbon. By Richard Phillips, F.R.S. E. and F.L.S. and Michael Faraday, Chemical Assistant, R. I.

It is remarkable, that another compound of these substances should be found so soon after the discovery of the two just mentioned.

This substance was formed accidentally during another process, and observed by M, Julin, who sent a portion to

this country, where it was examined by the authors of this paper. By well conducted experiments on the very small quantity sent over, they determined with sufficient precision that it is composed of one portion of chlorine and two of carbon. The proportions of the former compounds are, the per-chloride, three chlorine and two carbon; the protochloride, one chlorine and one carbon.

No. 13. On the aëriform compounds of charcoal and hydrogen: with an account of some additional experiments on the gases from oil and from coal. By William Henry, M.D. F.R.S. &c.

This is a profound and ingenious examination of several points relating to the different species of carburetted hydrogen gas. The subject is closely connected with one on which we made some observations in a former number, when brought forward in the Bakerian Lecture for 1820, by Mr. Brande. The present paper contains a refutation of the views of that gentleman, or rather we should say, a re-establishment of the old doctrine, founded on the most decisive and accurate experiments, with respect to one part of the subject, viz. the existence and composition of the simple carburetted hydrogen: whilst on the other hand, olefiant gas, which Mr. Brande considers the essential ingredient in the gases obtained from coal, seems from these experiments not to exist in those gases; they only contain a gas which resembles it in some peculiar properties, but whose composition is different, and as yet, undetermined.

The author first examined the gas commonly considered as carburetted hydrogen, and which has also been repeatedly examined by other chemists: he determined its specific gravity, and several properties; and finding the results obtained by different modes, and under very different circumstances, all nearly the same, he concludes, that there can be no reason for refusing to consider it a true chemical compound, having uniform properties and composition. He then exhibits the atomic composition of carburetted hydrogen, and olefiant gas. The former is one atom charcoal to two atoms hydrogen; the latter one atom of each.

He then tried experiments as to the action of chlorine on carburetted hydrogen; and found, that a condensation was produced when they were exposed for a short time to the common light of day; but none whatever if light were completely excluded. He found the reverse to be the case with olefiant gas, which is condensed by chlorine in the dark. This, therefore, became a method of analyzing a mixture

2

of these gases which he found susceptible of great pre

cision.

The mixed gases from oil and coal, were now subjected to analysis by means of chlorine. These processes and their results are detailed; and upon the whole, it was found that the portion of these mixtures not condensible by chlorine consisted of carburetted hydrogen, carbonic oxide, and hydrogen, with a little azote, part of which may be traced to the impurity of the chlorine. No instance ever occurred to Dr. H. of a gas obtained from oil or from coal, which after the action of chlorine upon it with the exclusion of light, presented a residuum at all approaching to simple hydrogen gas; nor does he believe that such a gas can be generated under any circumstances of temperature, by which the decomposition of coal or of oil is capable of being effected.

Our author then proceeds to make some inferences, respecting the composition of that part of the gas from coal and oil, which is condensed by contact with chlorine. Here, however, he met with some unexpected anomalies; the same were also found by Mr. Dalton. The portion of gas condensed by the chlorine presented decided differences from olefiant gas. It considerably exceeds the olefiant gas obtained by the action of sulphuric acid on alcohol, both in specific gravity and combustibility. He conceives, that

"It may be either a gas, sui generis, hitherto unknown, and constituted of hydrogen and charcoal, in different proportions from those composing any known compound of those elements or it may be merely the vapour of a highly volatile oil, mingled in various proportions with olefiant gas, carburetted hydrogen, and the other combustible gases."

He then gives several presumptions in favour of each supposition, but rather inclines himself to the latter. The paper is concluded by a brief recapitulation of the principal inferences.

No. 15. (Part 2.) Some observations and experiments on the papyri, found in the ruins of Herculaneum. By Sir Humphry Davy, Bart. P.R.S.

This paper contains various remarks relative to the papyri; the experiments were chiefly performed by subjecting the MSS. to the action of chlorine which has properties tending to destroy the matter which caused the adhesion of the leaves, without injuring the MS. itself. The application of this method required extreme precaution. Sir H.

Davy considers the operation of fire to be by no means necessary to account for the state of these MSS. which is to be attributed to gradual decomposition from limited exposure to the operation of water and air.

No. 16. Observations on Rapthaline, a peculiar substance resembling a concrete essential oil, which is apparently produced during the decomposition of coal tar by exposure to a red heat. By J. Kidd, M.D. Professor of Chemistry at

Oxford.

This paper consists of minute details of the nature and properties of a newly discovered substance; important as extending chemical knowledge, but of little interest to the general reader.

No. 20. On the separation of iron from other metals. By J. F. W. Herschel, Esq. F.R.S.

This is a very profound and ingenious paper on a mode of performing an important operation in analysis, in which chemists have hitherto had but very limited success, the modes proposed being inadequate, tedious, and confined in their application. The indefatigable industry and profound sagacity however of Mr. Herschel, have succeeded in discovering a method of separating iron from all compounds, with the utmost precision, and with great facility.

The method is briefly this: to bring the solution to the maximum of oxidation which can be given it by boiling with nitric acid then just to neutralize it, while in a state of ebullition, by carbonate of ammonia; and the whole of the iron is precipitated.

The author then details the various precautions necessary to be observed in performing the operation. He next proceeds to explain it and considers the phenomenon as turning on a peculiar property of the peroxide of iron, viz. that it cannot exist in a neutral solution at the boiling temperature. This property is proved by several experiments. Examples are added of the analysis of some specimens of meteoric iron; and a peculiarly elegant process is described, in the application of the principle laid down, to the separation of iron from uranium: this is done by as it were inverting the process. The solution being de-oxidized; and then treated with an earthy carbonate; the iron passes in solution, and the uranium is separated. The whole paper deserves the close attention of every chemical student.