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real nature of this force, it will be more simple in our future researches to consider it as independent, and to give it, for facility of recognition, name peculiar to itself. According to an etymology well known in chemis try, I shall consequently name it the CATALYTIC FORCE of bodies, and the decomposition which it determines catalysis, in the same manner as the separation of the elements of a compound, by means of the usual chemica affinities, is called analysis. This force may be defined to be a power of bodies to bring into activity, by their simple presence, and without participa ting in it chemically, certain affinities, which at that temperature tow remain inactive, so as to determine, in consequence of a new distribution the elements of the compound, a new state of perfect chemical neutralization As this force acts in general in a manner analogous to heat, it may be inquired whether being variously graduated, sometimes by employing differ ently the same catalytic body, sometimes by the introduction of varios catalytic bodies in the same liquid, it will cause, as is often observed in the action of heat at different temperatures, different catalytic products,whether the catalytic force of a body can be exerted over a large number of compounds, or whether, as our experiments appear to indicate, only over certain bodies, to the exception of certain other bodies? But in the present state of our knowledge it is impossible to decide these questions. and many others that might be proposed upon the subject: their solution must depend on the results of future investigations. It is enough, for the present, to have shown, by a suflicient number of examples, the existence of this force, which, defined as it has been, diffuses a new light over the chemical reactions of organized bodies. We shall cite but one example There is an accumulation of diastase around the eye of the potatoe, which is not found in the tubercle or in the developed germ; we perceive in this point a centre of catalytic action, at which the insoluble starch of the tubercle is converted into gum and sugar, and this part of the potatoe will become the secreting organ for the soluble substances, which are to form the juices of the growing germ. It is not probable that the action mentioned is the only one of its kind in vegetable life; on the contrary, it may be presumed, that in vegetables, as well as in the animal body, a thousand catalytic effects take place between the tissues and the liquids, whence results the great number of different chemical compounds, the production of which, from the same brute matter, which we call blood, or vegetable juices, cannot be explained by any other known cause.Universelle, Nouv. Ser. Tome ii., p. 376.

-Bibliotheque

A. T.

Rep. Pat. Invent. Aug

Sixth Meeting of the British Association for the Advancement of Science.

The Annual Sessions of this Association were commenced by a meeting of the General Committee, at Bristol, on Saturday, August 20, and were continued throughout the following week. The arrangement was, that the Sections should meet at eleven o'clock every day during the week, and that the General meetings of the Association should be held at 8 o'clock on the evenings of Monday, Wednesday and Friday. The conclud ing meeting to take place on Saturday, at an hour fixed by the General Com mittee. Several public dinners were given, and an ordinary was provided daily, at the Horticultural rooms, for strangers, at 5s. per head. The number of members in attendance exceeded that of any previous meeting,

and amounted to about 1350. The business of the Association is conducted by several Committees and Sections, as follows: Section A. Mathematical and Physical Science.

President, REV. W. WHEWELL.

B. Chemistry and Meteorology.

President, REV. PROF. CUMMING.

C. Geology and Geography.

President, REV. DR. BUCKLAND.

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The President of the Association was the Marquis of Landsdowne, who was prevented from attending by the illness of his eldest son, the Earl of Kerry, who died during the week of the Sessions. The chair was taken by the Marquis of Northampton, one of the Vice Presidents.

The business of the week appears not to have been excelled, in point of interest, by that of any prior meeting of the Association. Most of the British Savans whose names are well known throughout the scientific world, were present, except that among those whose names now occur to us, and which we do not find in the list of attendants, are Faraday, Airy, and some others. Among the learned strangers, were Baron Dupin of the French Institute, and Dr. Hare of Philadelphia. The latter was elected one of the Committee of Section B. His several communications were evidently received with most respectful attention, and at the public dinner, where nearly 500 persons were present, we find him on the right of the chair next to Prof. Whewell.

The interest excited throughout the week, (observes the correspondent of the London Athenæum,) cannot be conceived by those who were not present. The mass of interesting matter brought forward was quite unexpected. Prof. Sedgwick said that the present meeting was worth all previous ones put together-that now the British Association was really advancing Science, all the branches of which were becoming more and more connected with each other. The new views of Physical Science brought forward at the Geological Section, were the most important advances yet made in Geology. This would gradually be numbered among those branches of knowledge under the dominion of mathematica! laws, and be eventually placed in the same ranks with her kindred sister Astronomy."

The sum devoted to scientific enquiries during the ensuing year exceeds £2700! The next meeting of the Association is to be held at Liverpool, rather later in the year than the present; the day to be fixed by the General Committee.

The office bearers chosen for the meeting in 1837, are the Earl of Burlington, President; Dr. Dalton, Sir Philip Egerton, Rev. E. G. Stanley, Vice Presidents; Dr. Charles Henry, Mr. Parker, Secretaries.

Our extracts from the published accounts of the various matters brought forward in the different Sections must, necessarily, be limited to a few of those that appear to possess the greatest novelty and interest.

Change in the Chemical character of Minerals induced by Galvanism. By R. W. Fox. This communication was from a gentleman long known in connexion with Science, and largely connected with the mining districts of Cornwall. Nothing which occurred at the meeting appears to have produced a higher interest than this communication, and the one which imme diately followed.

Mr. Fox exhibited the extraordinary experiment of the change of yellow into the grey sulphuret of copper. In a trough a mass of clay was placed so as to divide it into two portions, in one of which was sulphate of copper in solution, in the other dilute sulphuric acid. On the electric communi cation being made by placing the yellow sulphuret in the solution, and a piece of zinc in the acid, the change of the sulphuret took place, and crystals of native copper were also formed upon it.

Mr. Fox then made some remarks upon the electro-magnetism of veins. It was plain that when a rock contained mineral matter, the rock and its contents must be in different electrical states, so that electricity must exist in very great activity in the interior of the globe. He referred to his experiments recorded in the Transactions of the Geological Society, He alluded to the north-east and south-west directions of the Cornish veins, and he had ascertained that there are Voltaic currents perpendicular to the magnetic meridian. Tin is found to exist in veins, or in different parts of the same vein; and, in experimenting, he found that metallic tin went to the positive, and oxide of tin to the negative pole of the apparatus. He was also struck with a kind of polarization in the disposition of the matter of veins; thus, iron and copper presented distinct relations to each other; the grey sulphuret of copper was uniformly found above the yellow; the quartz of N. and S. veins were striated, that of E. and W. veins not so. The phenomena of the intersection of veins were also spoken of; the old suppo sition, that one vein must be older than the other, need not be resorted to in all cases, as it could be proved that crossing veins were often of simul taneous origin.-Dr. Buckland pointed out Mr. Fox's experiment as an illustration of the simplicity of the means which nature had adopted in her most subtle operations, and expressed his hope that this new application of electro-chemistry to geology, would furnish a series of results of paramount importance. Indeed, one of the great benefits conferred by the British Association on science, was the bringing forward individuals who had devoted themselves in private, to scientific investigation and experiment, which often, as in the case of Mr. Fox, opened the portals that led to new views of nature and her operations. He had now to introduce to the notice of the Section another gentleman, who had for many years, in private seclusion, occupied himself in experiments of a novel and extraordi nary character, and also making use of apparatus of the most simple description. He then presented to the notice of the meeting, Mr. Cross, who would give a verbal account of his most singular proceedings.

Artificial Crystals and Minerals. A. Cross, Esq. of Bloomfield, Somerset, then came forward and stated that he came to Bristol to be a listener only, and with no idea that he should be called upon to address a Section. He was no geologist, and but in a moderate degree a mineralogist. But, being early impressed with the notion that it would be desirable to produce, if possible, a long continued, undiminished electrical action, he had set himself to work, and after many trials he had constructed an apparatus, which had for no less than an entire year retained its electric energy, and

this by the agency of pure water only. He had also conceived, that it being by long continued processes that nature produced most of the effects which we observe, it might be possible to form substances similar to what she affords, by adopting a mode like hers. His attention had been directed to a cavern in the Quantock Hills, in which he had observed calcareous spar incrusted on limestone, and arragonite on clay slate: these minerals had evidently been formed by the water which percolated the rocks. Some of this water he brought to his house, and presented it to the action of his Voltaic apparatus; for nine days he anxiously watched for a result, but no visible one offering, he had almost given up the experiment, when on the tenth day, to his great delight, he succeeded in procuring minerals the same as in the cavern. He was thus encouraged to prosecute further experiments; and, in the course of his investigations, he found that light was unfavourable to the perfection of crystals, he being enabled, in a much shorter period, and with much weaker electric power, to produce them in the dark. He formed several crystals of metallic minerals, but his most successful experiment was the production of quartz from fluo-silicic acid, and his inspection of what has been perhaps never before observed by mortal eye, the process of crystalline developement from the beginning. He had traced a quartz crystal, first, as a hexagon marked upon the matrix-then lines radiated from its centre then parallel lines were formed parallel to its sides-it increased in thickness, but, owing to some disturbance of the operation, the, process of forming a single perfect crystal was not completed, for a second crystal grew up and intersected it, offering an additional confirmation of the resemblance of Mr. Cross's process to that of nature, where this penetration of crystals into each other is every where to be observed.

It would be extending this report too far to relate all that Mr. Cross communicated to the Section regarding the details of his experiments; but it is impossible to convey an idea of the enthusiasm with which his statement was received by the crowded assembly present. There appeared to be a real electrical effect produced upon them; they seemed as if the interior recesses of Nature had been of a sudden laid open to them, and her processes, which had been conceived as past all mortal ken, submitted to their inspection. Mr. Cross was often interrupted during his address with loud peals of applause, which lasted for several minutes after he sat down.Mr. Conybeare said, that he found himself so excited with the intelligence, that he should not submit his observations on the South Wales Coal Basin; he considered any communication he could bring forward totally eclipsed in interest by the overpowering intelligence brought by Mr. Cross. Upon that gentleman Mr. Sedgwick passed also a highly eloquent eulogium. Professor Phillips stated, that he had now hopes of realizing his fondest dreams of geology. He had long conceived that Nature must have some means of conveying solid matter through solid matter, and that this was now proved by Mr. Cross, whose discoveries were of such importance, that had the British Association been of no other service than in bringing them to light, they alone were worth all the pains it had taken for the advancement of science, and it was its particular business to have experiments like his set on foot, and prosecuted for many years to come.

It was mentioned to the Section on the following day, that although no doubt could be entertained of the independence and originality of Mr. Cross's experiments, yet that he had been anticipated in the artificial production of many of the crystalized bodies which he had formed, by M. Becquerel and some other French Chemists.

VOL. XVIII.-No. 5.-NOVEMBER, 1836.

29

Change in the Chemical character of Minerals induced by Galvanism. By R. W. Fox. This communication was from a gentleman long known in connexion with Science, and largely connected with the mining districts of Cornwall. Nothing which occurred at the meeting appears to have produced a higher interest than this communication, and the one which imme diately followed.

Mr. Fox exhibited the extraordinary experiment of the change of yellow into the grey sulphuret of copper. In a trough a mass of clay was placed so as to divide it into two portions, in one of which was sulphate of copper in solution, in the other dilute sulphuric acid. On the electric communication being made by placing the yellow sulphuret in the solution, and a piece of zinc in the acid, the change of the sulphuret took place, and crystals of native copper were also formed upon it.

Mr. Fox then made some remarks upon the electro-magnetism of veins. It was plain that when a rock contained mineral matter, the rock and its contents must be in different electrical states, so that electricity must exist in very great activity in the interior of the globe. He referred to his experiments recorded in the Transactions of the Geological Society. He alluded to the north-east and south-west directions of the Cornish veins, and he had ascertained that there are Voltaic currents perpendicular to the magnetic meridian. Tin is found to exist in veins, or in different parts of the same vein; and, in experimenting, he found that metallic tin went to the positive, and oxide of tin to the negative pole of the apparatus. He was also struck with a kind of polarization in the disposition of the matter of veins; thus, iron and copper presented distinct relations to each other; the grey sulphuret of copper was uniformly found above the yellow; the quartz of N. and S. veins were striated, that of E. and W. veins not so. The phenomena of the intersection of veins were also spoken of; the old suppo sition, that one vein must be older than the other, need not be resorted to in all cases, as it could be proved that crossing veins were often of simul taneous origin. Dr. Buckland pointed out Mr. Fox's experiment as an illustration of the simplicity of the means which nature had adopted in her most subtle operations, and expressed his hope that this new application of electro-chemistry to geology, would furnish a series of results of paramount importance. Indeed, one of the great benefits conferred by the British Association on science, was the bringing forward individuals who had devoted themselves in private, to scientific investigation and experiment, which often, as in the case of Mr. Fox, opened the portals that led to new views of nature and her operations. He had now to introduce to the notice of the Section another gentleman, who had for many years, in private seclusion, occupied himself in experiments of a novel and extraordi nary character, and also making use of apparatus of the most simple description. He then presented to the notice of the meeting, Mr. Cross, who would give a verbal account of his most singular proceedings.

Artificial Crystals and Minerals. A. Cross, Esq. of Bloomfield, Somerset, then came forward and stated that he came to Bristol to be a listener only, and with no idea that he should be called upon to address a Section. He was no geologist, and but in a moderate degree a mineralogist. But, being early impressed with the notion that it would be desirable to produce, if possible, a long continued, undiminished electrical action, he had set himself to work, and after many trials he had constructed an apparatus, which had for no less than an entire year retained its electric energy, and

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