and had neither been used, nor exposed to the rolling or abrading action of water in motion. It was found in the Chamber, 53 feet from the external entrance, in the fourth foot-level below the stalagmite, which was from 12 to 15 inches thick and extended uninterruptedly for considerable distances in every direction. The lanceolate "implements" are of two kinds-round-pointed and sharppointed. They are widest near the posterior extremity, and one surface has usually a central longitudinal ridge or keel, whilst the other is flat, or concave lengthwise, but which, whether flat or concave, appears almost invariably to have been produced at a single stroke. Of the round-pointed variety, a wellformed specimen was found in the Chamber, 46 feet from the entrance, in the upper part of the first level or foot of cave-earth, immediately below the stalagmite, which, at this part, was from one and a half to three feet thick. It measures about two inches long, and three-quarters of an inch broad; it is strongly carinated on one side, and longitudinally concave on the other. A second and still finer " implement measures nearly three and a half inches long, rather more than one inch in greatest breadth, and four-tenths of an inch thick. It differs from the former in a few particulars. The central longitudinal ridge, at about an inch and a half from the hinder end, bifurcates symmetrically as if a small flake had been struck off. Hence the carinated side has three distinct surfaces, each of which is very slightly concave. There are several small facets, each produced, no doubt, by a separate and well-directed gentle stroke on the rounded anterior extremity, which seems too thick to render it probable that the "implement" could have been intended to be used as a spear-head. But for these facets, the "implement," though beautifully and very symmetrically shaped, appears to have required no more than four strokes for its formation; but in order to do this, the fracture must in each case have been remarkably clean. Indeed the beautiful smoothness by which all the surfaces are characterized suggests a doubt as to whether it may not have been produced by some degree of polishing. The small facets, however, are perhaps scarcely in keeping with this hypothesis. Its posterior extremity is not sharply truncated, but somewhat irregular, and both its lateral margins are slightly broken. It was found very near the centre of the Chamber, 2 feet deep in the red earth, and having over it a thick floor of stalagmite. Like the specimen previously described, it is formed of very fine-grained flint of a light cream-colour. On one side it is longitudinally concave. The "implements" belonging to the second variety differ from these not only in being sharp-pointed, but in tapering more rapidly near the anterior extremity, in terminating in a thinner point, near which the keel, instead of ⚫ being rectilineal, is gently curved, and the lateral margins, instead of being symmetrical, are one slightly convex and the other concave, conforming, in fact, to the deflection of the central ridge. In one specimen there are, on the flat side and near the point, several very small marginal facets. This fine "implement," or rather portion of one, is of whitened flint. It was found in the Chamber, 48 feet from the entrance, in the third level, beneath a thick floor of stalagmite. Amongst the lanceolate "implements" there is one sharply truncated at both ends, the point probably having been broken off. It is 3 inches long, but when entire must have measured another inch; its greatest width somewhat exceeds 1 inch. The flat side has been produced by a series of blows, and suggests the ideas that the stroke which detached the "implement " from the flint core left this a somewhat irregular surface; that a near approximation to flatness, and especially smoothness, on this side was essential to the performance of the work for which the tool was to be used; and that the requisite character was produced by numerous minute chippings carefully and skilfully directed. The obverse also contains evidence of a more than usual amount of work. It has two somewhat irregular and rudely parallel longitudinal ridges, as well as several facets. The lateral margins are not quite symmetrical. It is formed of fine-grained flint, of a light lead-colour inclining to whiteness; and it was found in the Chamber, 49 feet from the external entrance, 3 feet deep in the red deposit, and covered with a thick stalagmitic floor. The only specimen of the third or ovoid class found since the First Report was presented is quite the finest "implement" which has been exhumed during the present exploration. It measures 44 inches long, 3 inches in greatest breadth, and about 1 inch in maximum thickness. It is strictly oval in form, being wider at one end than at the other. Like the fine "implements" of the same class described in the former Report, it is formed of a somewhat coarse-grained greyish flint. The bilateral symmetry of its outline is sensibly perfect. Its opposite faces differ somewhat in convexity; each of them, and especially that which is most convex, displays a large amount of chipping. This splendid tool was found 55 feet from the entrance, 8 feet from both the northern and the western wall of the Chamber, in the fourth foot of cave-earth, or the lowest yet excavated, beneath stalagmite which was about a foot thick and extended without a break for several yards in every direction; and it was dug out in the presence of one of the Superintendents and two gentlemen who accompanied him to the cavern. Besides the foregoing "implements," all of which, as has been stated, were found in the Chamber, there is one which was met with 8 feet from the inner end of the Gallery, or 83 feet from the external entrance of the cavern; and which seems to connect the lanceolate and ovoid classes, resembling the first in being pointed, and the second in being worked to an edge round its entire perimeter. Its dimensions are less than those of any oval, and its breadth, in proportion to its length, exceeds that of any lance-shaped "implement " which the cavern has yielded. It is 3 inches long, and in greatest breadth and thickness measures an inch and three-quarters and four-tenths of an inch respectively; it is nearly an inch and a quarter wide at the broad end, attains its maximum breadth about midway in its length, and has lost its extreme point. It is formed of fine-grained flint of a cream-colour, and differs from all the other cavern "implements" in having what may be conveniently termed a "varnished" or "glazed" surface. This "implement," which seems to have experienced rough usage, was found in the second foot-level below the stalagmite, which, in the Gallery, as already stated, is the lowest composed of true cave-earth. Though, as has been stated, the lower levels have, on the whole, yielded fewer implements" than the upper, it is still true that "those found in the third and fourth levels are the most highly wrought implements,"" and also that "those in the fourth or lowest zone are the most elaborately finished tools of the cavern series." In glancing over all that have been dug out during the present exploration, it appears that whilst there are several interesting tools from the first level, and a larger number from the second, neither of these zones has yielded an ovoid "implement;" that from the third belt were exhumed the first oval and the two best lanceolate forms; and that the two oval tools found in the lowest level are very decidedly the most carefully finished specimens which the cavern has yielded. In the present stage of the investigation, the Committee think it neither desirable nor necessary to enter into any arguments to prove the artificial character of at least many of the flints which they have found. Indeed they speak for themselves; and in terms so unmistakeable that if they do not succeed in carrying conviction to the mind of the observer, any words that could be employed must certainly fail also. It will be of interest, however, to call attention to certain other evidences of human existence found in the cave-earth. As already remarked, it was stated in the First Report that a whetstone had been found below the stalagmite. Very shortly after that Report was drawn up a second stone was met with, formed of a fragment of similar, though somewhat finer-grained, greenish grit. Its form is not quite the same as that of the first specimen. Mr. Franks states that "it closely resembles some stones found in the Bruniquel caves, in form and material." It was lying in the first level of cave-earth, 43 feet from the entrance, where the overlying stalagmite was 26 inches thick and extended many yards in every direction. Several pieces of burnt bone were found in the cave-earth in the Gallery— some near the extreme, and others near its inner end. One of them was found in the first, and one in the third, but most of them in the second footlevel. In each case the deposit was overlain by a thick cake of stalagmite. Burnt bones have been found in the red earth in several parts of the Chamber also. In conclusion, the Committee would remark that the careful and unremitting labour bestowed on the cavern during the last year and a half has produced a large accumulation of facts, consistent with one another and with those recorded by the earlier explorers. Of the discoveries made, the uniform testimony is that beneath a thick floor of stalagmite, so difficult to work as to require excellent tools and untiring perseverance, there are everywhere found, inosculating with bones of extinct mammals, and undoubtedly inhumed at the same time, human industrial remains, of a character so humble and so little varied as to betoken a very low type of civilization. Preliminary Report on the Chemical Nature of Cast Iron. In the Transactions of the British Association for 1863 it was pointed out, in 66 a Report on the Chemical Nature of Alloys," that alloys may be, when in a solid state, (1) Solidified solutions of the one metal in the other; (2) Chemical combinations; (3) Solidified mechanical mixtures; (4) Or solidified solutions of mixtures of any of these. It is important to clearly understand what is here meant by the term. "solidified solution," for in speaking of alloys they are generally considered to be either mechanical mixtures or chemical combinations. In the "Report on the Chemical Nature of Alloys," I have defined the terms "solution of one metal in the other, as one like that of ether and alcohol; for these two liquids may be mixed in any proportion, and they will not separate, by standing, into two layers," and "solidified solutions as a most intimate mixture, such as would occur in the sudden conversion of a solution of two liquids into a solid, and a much more intimate mixture than can be obtained by ordinary mechanical means-in fact a perfectly homogeneous diffusion of one body in another. An excellent example of homogeneous diffusion is furnished by glass, which is formed in a liquid state at a high temperature, and solidifies on cooling without separation of the different silicates." Before deducing the chemical nature of cast iron from what is already known, it will be as well to compare the physical deportment of the alloys of carbon and iron with that of other alloys; for instance, with those of tin and copper, and zinc and copper. Pure iron is said to be very malleable, so is pure copper; iron alloyed with small quantities of carbon (malleable, wrought iron) is less malleable and harder than the pure metal; so is copper, when alloyed with small quantities of tin or zinc, less malleable and harder than the pure metal. Iron alloyed with from 1 to 2 per cent. of carbon has obtained its maximum state of hardness in conjunction with a certain degree of malleability and ductility (steel); copper alloyed with certain quantities of tin or zinc possesses similar properties, forming gun-metal and brass. Again, increase the amount of carbon in the iron and the mass becomes brittle and unworkable (cast iron); so also do the alloys of copper, and tin or zinc, when the amount of the latter exceeds that contained in gun-metal or brass by a few per cent. Leaving out of consideration the impurities of cast iron, let us first discuss the alloys of carbon and iron, and these we find may be divided into two classes, viz. the white and the grey cast iron. Now the essential difference between these two forms is the state in which the carbon exists in them. In the one (white) it is said to be chemically combined with the iron, in the other (grey) mechanically mixed with the iron. As these, the white and the grey iron, may be converted into one another by re-fusion (for if certain sorts of white iron be fused at a low temperature and allowed to cool slowly, grey will be produced, and conversely, if grey iron be fused at a high temperature and cooled rapidly, white iron), it follows that the chemical combination of carbon and iron may be made to split up into its component elements simply by slowly cooling the molten mass. Bearing on this point are the following experiments made by Karsten: he took a mass of cast iron and determined the amounts of so-called chemically combined and uncombined (graphitic) carbon in it; he then melted it and cast it in a mould, analyzed the outer and inner portion of it. The following are the results he obtained: Now, can it be possible that the carbon is really chemically combined with the outer portion of the casting and not in the inner? if this be so, it is I think the only case known of a chemical combination in which the elements are so loosely held together that the various rates of cooling will determine their combination or decomposition. From the analogy of the alloys of carbon and iron with other alloys, it is possible that the case is as follows; namely, that the carbon and iron exist in the molten state as a solution of the one in the other-when in the white state as a solidified solution of carbon in iron, and when in the grey state as a mechanical mixture of carbon and iron. If the above assumption be correct, then the conversion of white into grey cast iron, and vice versa, may be easily explained; for if in the liquid state the carbon and iron be only a solution of carbon and iron, then we can easily understand why the carbon, when the molten mass is heated to a high temperature and cooled slowly, crystallizes out, and when cooled quickly, not having time to crystallize out, remains homogeneously diffused through the iron; as it is very probable that molten iron will dissolve more carbon at higher temperatures than at lower ones. The two chief reasons for assuming that the carbon and iron exist in the state of chemical combination are, (1) That when white iron is dissolved in dilute acids, the carbon combines with the hydrogen, forming carburetted hydrogen. (2) That different carbides of iron have been isolated. First, respecting the chemical behaviour of the carbon in the white iron, the following remarks may be made. If it be assumed that the carbon in cast iron is homogeneously diffused through the mass, then it must be in an exceedingly fine state of division-in fact in just the state for combining with other bodies; for it is well known that carbon as well as other substances possess properties, when in a state of fine division, which they do not possess when in a more coherent form. Thus in the case of carbon, the more porous it is the more active it becomes in dechlorizing liquids and absorbing and condensing gases in its pores. Platinum is also a good example of this fact; in a dense form, as in foil, it only possesses the property of condensing gases on its surface to a very feeble extent; in its spongy form it possesses this property in a very marked degree, and as platinum-black possesses it to a far greater extent than the spongy modification. As another example of the influence of the chemical activity of bodies when in a fine state of division, we may take the cases of iron, lead &c., these metals, when in a coherent form, undergoing when exposed to the atmosphere only a very slow oxidation, but when in a very fine state of division (reduced oxides) combining with oxygen instantly. The chemical behaviour of the constituents of alloys is sometimes different when in an alloy from what it is when alone; thus platinum when alloyed with silver dissolves to a certain extent in nitric acid. Now, taking the determinations of the conducting-powers of alloys as a means of testing their chemical constitution, I should with certainty say that there exists in the alloys of platinum with silver no chemical combination, for their observed and calculated conducting-powers agree together better than for any other series of alloys. The curves representing the conducting-powers of the alloys of these metals with one another possess the typical form of the alloys of that class of metals to which these belong. 2ndly. With regard to the definite chemical combinations which have been isolated from cast iron, it may be remarked that definite crystalline forms with alloys do not necessarily indicate chemical combinations. Cooke, I believe, * Memoirs of the American Academy (new series), vol. viii. p. 27. |