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found to coat only those surfaces which face in a peculiar direction, is well worthy of attention in the study of these obscure phenomena.” Besides the Spathose ores of Weardale, we have the same ores occurring in great abundance on Exmoor, and they are worked extensively on the Brendon Hills, near Watchet, over a length of nine miles, to Eisen Hill. At Perranzabulæ, on the north coast of Cornwall, a still more remarkable deposit of these ores exists, but at the present time they are but slightly worked. In the northern corner of Perran Bay a lode appears in the cliff, with a width of nearly 100 feet, and it has been traced for some miles inland and worked at several points. Beyond this brief notice, space cannot be given to the further consideration of these most interesting Iron ores.

The Argillaceous Iron Ores of the Lias.—The Cleveland Iron ore is the finest example we have of this class of ore. The immense extent of this deposit, the value of the Iron works which have arisen amidst the Cleveland Hills, places this district amongst the first of our Iron-producing districts.

This remarkable deposit may be traced by its outcrop for miles along the escarpments of the Cleveland Hills. Above the flat land which extends from Redcar to Middlesborough there crops out a solid stratum, often fifteen feet in thickness, of this Iron-stone. It is a deposit of a green or grey colour, having generally an oolitic structure, and containing numerous well-known fossils of the Marlstone, especially Belemnites and Pecten Æquivalis. The plan and section, Figs. 7 and 8, will show the mode of occurrence of this ore. This vast ferruginous deposit is composed, to a great extent, of Carbonate of Protoxide of Iron. We know that such a deposit could not be formed, unloss it was precipitated from water charged with Carbonic acid in excess. We have no evidence that such conditions ever prevailed, to the required extent, over this district, when those Iron-stone beds were being formed. Mr. Sorby has drawn attention to the fact that if the Iron-stone be examined it will be seen that it contains, more or less, entire portions of shells. All the indications appear to show that the Cleveland Iron ore was deposited probably as a limestone, containing a large amount of the oxides of Iron and organic matter. By their mutual reaction these would give rise to the bicarbonate of Iron, which in solution, percolating through the limestone, would remove a large part of the carbonate of lime and leave in its place carbonate of Iron.

It is our object in writing this paper, to draw more especial attention than has hitherto been done to the Hematites, and the Argillaceous Carbonates of the coal-measures, as related to each other, in their mode of formation.

It will be evident to everyone who carefully studies the conditions of the clay band Iron-stones spread out in beds amongst the seams

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of coal and coally shale, that they have been associated in some way with the formation of the coal itself. As the coal deposits have been produced by a series of chemical changes in vegetable matter, spread over an immensity of time, so have the Iron-ore deposits, as we find them, been the result of sundry changes carried out upon the older rocks, those especially which belong to the Devonian or Old Red Sandstone period. The enormous deposits of Sandstones and Shales formed in our coal basins prove the gigantic nature of the denudations which have taken place, and which have produced the sedimentary beds, as they are placed before us, striking records of the world's mutations. From all that remains of those older rocks we know how highly ferruginous they were. The waters of the coal period swept around Old Red Sandstone rocks, and the plants from which our fossil fuel is derived grew upon the soil produced by the disintegration of these formations.

Let us study for awhile the phenomena which, in all probability, took place. As we now find at the mouths of great rivers,—especially within the tropics,—vast masses of vegetable matter, undergoing a series of changes, in the process of decay, so must we suppose the condition of a swamp, of an estuary, a lake, or inland sea, to have been, when the vegetable matter of an ancient world was rotting, in its progress towards coal. The result of the change was the formation of immense quantities of carbonic acid, and this would be largely retained by the water holding vegetable extractive in solution. This water would rapidly dissolve any limestone with which it came in contact, and would change the peroxide of Iron in the rocks into a protoxide; which would be eventually dissolved, either as a carbonate of the protoxide of Iron, or in water holding an excess of carbonic acid, as a protoxide merely. Experiment shows this satisfactorily. Place recently precipitated peroxide of Iron in a shallow vessel with a large quantity of dead leaves and water; expose this to the ordinary atmospheric changes; it will be found eventually, that the peroxide will be changed into a protoxide and dissolved. Under some conditions,—especially if the Arrangement is made part of a voltaic circuit,-crystals of carbonate of Iron will be the result; and under others an accretion of amorphous carbonate will form around small fragments of vegetable matter, producing indeed, in miniature, the clay-band Iron-stones of the coal measures.

Now, if the water flows away from the influence of this mass of vegetable matter in its state of change, and if it be exposed in a thin sheet, to the action of the atmosphere, the Iron in solution will be rapidly oxidized and it will fall to the bottom of the vessel as peroxide of Iron.

These results appear to teach us that the present conditions of

our coal measure Ironstone formations were the direct result of the process of coal formation, the water in which the coal was formed removing from the surrounding rocks, by virtue of the dissolving power of carbonic acid, the Iron which they contained; this, if retained within the coal basin, gradually produced the argillaceous carbonates of Iron as we find them, but if the ferruginous waters passed away from the influence of the dissolved vegetable matter, then oxidation ensued, and hence the deposits of Hæmatite in ponds and fissures as we see them near Ulverstone. The same carbonized water had previously been active in dissolving the limestones formed around the coal basins, and into the cavernous spaces thus formed,and these are common in all our carboniferous limestone districts

- the peroxide of Iron was deposited, as at Whitehaven, in the Forest of Dean, and in Glamorganshire.

Further study is required before it can be certainly determined whether or not the chemical changes indicated, are those only which have been active in producing our Iron ores as we now find them. It is, however, believed that the hypothesis put forward will serve to explain most of the conditions which are presented to the careful observer. They are, at least, honest attempts to read the phenomena which are presented to us in the varied conditions under which we find the most useful of the metals, IRON, occurring in the inorganic world.

VI. ON MEDICAL SCIENCE: ITS RECENT PROGRESS

AND PRESENT CONDITION.

The season which has passed away, although not especially fertile in the fruits of the earth, has not been deficient in those of the mind. The intellectual harvest, gathered at the autumnal meetings of learned and scientific societies, at statistical congresses, and other assemblages of men earnestly engaged in the pursuit of common objects, has been plentiful and of perhaps more than average quality. We have already registered many of these products, but there is one class of them, which, from its purely technical nature and the unfitness of many of its details for public discussion, is rarely noticed, except in Journals strictly professional; and yet it relates to matters in which we are all deeply interested. If there is any subject which “comes home to our business and bosoms,” it is that of Medicine. Next in importance to the supply of our daily wants of food and clothing, is the care of our health, and the improvement of the means of its conservation is a topic to which none of us can be indifferent; an occasional survey, therefore, of the condition of Medical Science, free from objectionable details, may fitly find a place in a Journal designed for general circulation.*

We have before us the papers read at the Dublin meeting of the British Medical Association, the communications to various provincial meetings of the same body,"contributions to the Journals, and last, but by no means least in value, the addresses delivered at the opening of the winter session at the different medical schools, metropolitan and provincial. The conclusion to be drawn from these various sources of information as to the recent progress and present condition of Medical Science is a most encouraging one. In no former period of equal length have such advances been made as in the last half-century in the detection of diseased action or morbid change, and if equal progress has not been made in the Art of Medicine, in the application of Science to the prevention of death or the relief of suffering, still even in that respect the advances have been immense. The practitioner now undertakes with confidence the treatment of diseases which his predecessors regarded as incurable, and the modes of treatment have, in many instances, been simplified and made less painful.

A recapitulation of some of the additions thus made to the means of combating disease ought to be specially interesting to the readers of a Journal like ours, for it has been strictly and exclusively by the means of research furnished by experimental science, that our knowledge of disease has been extended, and if wise empiricism, or happy imagining (the inspiration of genius), has, rather than scientific research, furnished the improved methods of treatment, Science has provided the means of utilizing the thoughts thus suggested. .

But leaving these generalizations, let us proceed to a few details, and first of the improved methods of research. Of these the foremost has been the extension of the power of vision by the microscope. The additions to our stores of knowledge, both of healthy structure and of morbid changes, thus acquired, would fill volumes; and we have not space for the enumeration of even a few of them.

Next, in point of value, should be placed the discovery which to some extent does for the sense of hearing what the microscope

* We think it right to say that, in making such a survey, we take as our guide and as a sketch-map of the country over which we intend to travel, an address recently delivered before the North Wales branch of the British Medical Association, by its president, Mr. Thomas Eyton Jones, of Wrexham. In choosing such a guide, we are not alone influenced by the intrinsic merits of the address, as a lucid and comprehensive abstract of the recent progress of medicine, but we have pleasure in showing that not only in our great cities, the centres of mental activity, is medical science studied with earnestness, but that the men living in remote provincial towns, and practising among widely scattered populations, are able to keep pace with, and to rival their more favourably situated brethren.

materimode of research.And an equal examination, the the sounds

does for the sight. We know not who first applied his ear to the walls of the chest, to endeavour to learn, from the sounds thence emitted, the variations in the action and conditions of the organs therein contained; but he who first thought of interposing between the ear and the naked body a tube of some unyielding material, and thus made mediate auscultation an universally applicable mode of research, deserved to be ranked among the greatest benefactors to mankind. And an equal rank should be given to the inventor of percussion as a mode of examination, the man who first showed that by close attention to the varied quality of the sounds produced by a smart blow on the walls of the chest, most precious knowledge might be obtained of the condition of the contained viscera.

The sense of touch also has not been without its cultivators. The tactus eruditus has long been one of the most highly valued acconiplishments of the surgeon, but improved methods of palpation have made it almost equally useful to the physician; and most valuable additions have recently been made to the information which the touch gives as to the pulse. The knowledge gained by gentle pressure with the tips of the fingers on a superficial artery, of the frequency, force, and other qualities of the action of the organs of the circulation, is necessarily uncertain, because it is subjective knowledge, and because therefore the accuracy of the observations must depend on the carefulness and experience of the observer, and the delicacy of his sense of touch. A beautifully imagined instrument now registers for us the pulsations, and describes on paper the height, form, and other qualities of each arterial wave. We must also regard as helps to the sense of touch the improved modes of applying the thermometer to the surface and the cavities of the body. Most precious knowledge is thus acquired as to the progress of febrile and inflammatory diseases, and our powers both of prognosis and of diagnosis have been immensely increased.

To all these modes of rendering medicine more and more one of the exact sciences, must be added the improved modes of research furnished by chemistry. Our knowledge of the composition of organic bodies, and of the chemical changes constituting assimilation and degeneration, and of the processes of growth, secretion, and excretion, has only within the last quarter of a century acquired anything like the character of certainty. The physiological chemist has not only entered so far into the arcana of Nature as to be able to ascertain, to a great extent, how she does her work, but has even succeeded in imitating her operations. Not content with analysis, he has with considerable success attempted synthesis also. “ Already he has been able to produce a large number of organic compounds from carbonic acid, water, and ammonia, and even from the pure elements themselves. In fact, of the three great classes of alimentary substances, the production of the oleaginous is quite

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