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his paper, published a few years back, on the Gault of that locality, A still more important one, however, is that by Herr Clemens Schlüter, of Bonn,* on the distribution of the Cephalopoda, in the upper cretaceous beds of North Germany. In this long and most valuable paper the author describes thirteen zones, giving a list of the cephalopods found in each, and terminates his paper with a table showing the vertical distribution of each of the hundred and fifty, five species enumerated. This table brings prominently to light the remarkable way in which the different species are confined to the several zones, only a few being common to two or three consecutive horizons.

Below the loess of the Danube near Zeiselberg, at the mouth of the Kamp valley, a rich deposit of bones was found in 1876, by Count Wurmbrand,t and below this a blackish stratum abounding with fragments of charcoal and worked flints. The bones were those of the mammoth, rhinoceros, reindeer, and other pleistocene mammalia. “The local conditions,” we are told, “contradict the supposition that these remains were carried to their present position, from a distance, by currents of water or other agency.” This section is still being worked out.

In his article “ On the Loess of the Rhine and Danube," | Mr. Belt must have stretched his theory of the “glacial epoch” to its utmost limit. This fine alluvial loam extends far up the valleys, and is found at heights considerably above the present level of the rivers. It was deposited at a time when these rivers were larger and more powerful, and before they had excavated their valleys their present depth. Mr. Belt, however, considers it to be merely the southern continuation of the Boulder Clay, and deposited in the manner already advocated by him in previous papers, when treating of that formation. We are asked to believe that an enormous glacier of freshwater ice issued from the north, crept down the basin of the Atlantic, blocking it up and rearing its snowy crest some seventeen hundred feet above the modern sea level! The drainage of the continent being thus dammed back, a huge freshwater lake was

* Zeitsch. der Deutsch. Geo. Gesellsch., Bd. xxviii. Hft. 3. + Vienna Imp. Acad. Sci., February, 1877, and Geol. Mag., April, 1877. # Quart. Journ. of Sci., Jan. 1877 ; Geol. Mag. April, 1877.

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formed, on the surface of which the icebergs laden with boulders floated, whilst at the bottom the deposits in question were accumulating. The German Ocean, Mr. Belt tells us, in another paper, was in like manner choked up with ice, and a similar lake formed in East Anglia, in which were deposited certain brick-earths, and which, in draining to the south-west, cut through the Straits of Dover. Thus on the north and west the waters were held in by icy barriers ; but what detained them on the east or south does not apparently seem to have troubled Mr. Belt at all, for he does not offer any explanation on this point; nor does he for a moment consider the probable effect of the presence of so large a body of ice on the rivers themselves, for what would prevent their being completely frozen up? Mr. Belt's reason for thus invoking the aid of ice-bound lakes, appears to be his inability to accept the upheaval and subsidence of the land, as advocated by other glacialists. Instances are on record of a small lake being formed in a valley, across the mouth of which a glacier has crept, and the well-known "parallel roads" of Glen Roy testify to the former existence of a lake of this sort in our own country; but further evidence must be forthcoming before such an extended application of this phenomenon as advocated in the above instances can be admitted as even possible, much less probable.

Very different are the views held by Mr. Henry Woodward, as put forward in an article on the “Evidences of the Age of Ice.” + Mr. Woodward points out that the "question of the relative elevation of the land) above the sea-level has not had that prominence given to it in the discussion which it deserves." An elevation of a few hundred feet (and there are many proofs of such oscillations in the level of the land having taken place) would suffice to bring the greater part of Britain sufficiently near to the “snow-line” to produce all the results that could be obtained in shifting it bodily to the latitude of Greenland, by altering the axis of the earth. The whole question is, however, of so complex a nature that it will be long ere geologists arrive at a satisfactory conclusion concerning the “ice-age," and possibly they never will.

The introduction of the microscope into the geological field has been productive of great results, and in some cases has entirely

* Geol. Mag., April, 1877.

† Pop. Sci. Review, April, 1877.

tents."*

altered former opinions. Had it not been for the microscope, the theory of the chemical origin of the chalk might still have been in full force, and many a volcanic mass would be known by the conveniently ambiguous term of “Greenstone." One of the most remarkable discoveries made known by its aid is the occurrence of cavities in quartz and other minerals enclosing fluids, in which float gaseous bubbles. A most interesting account of these will be found in Mr. W. N. Hartley's paper on “Mineral Cavities and their Con

Attention was first directed to them in 1822, by Sir Humphry Davy, through the exact nature of their contents has been but recently ascertained. One of the fluids most frequently found in these cavities, especially in the topaz, is liquid carbonic acid containing a bubble of carbonic acid gas; on heating the slide the bubble of gas disappears, the space being occupied by the expanding fluid, but it reappears again when the slide cools, with an appearance of ebullition.

Not only does the microscope reveal the composition of rocks, but even in some cases tells us the source whence the component particles of clays and sands are derived, as shown by Mr. Sorby, in his presidential address to the Royal Microscopical Society.t

A very pretty little “Sketch Map of New South Wales, showing the localities of the principal minerals," intended for the use of emigrants and others, has recently been issued by the Australian Government. It shows at a glance the various spots in which gold, silver, copper, tin, iron, coal, kerosene shale, and diamonds, and other gems may be obtained. The back is devoted to "

general statistics,” ranging from the values of the different mineral areas, down to the price of provisions and the rates of wages. Some of the details given in these tables are so interesting that we regret that the nature of our report compels us to keep to the other side.

CHEMISTRY.-By S. P. THOMPSON, B.Sc., B.A.
F recent discoveries in chemical science none promises to be of

greater importance than one which has been lately announced in the public press, and has doubtless already met the eye of those readers of the ARGONAUT who study the columns of the Times, or the

OF

* Pop. Sci. Review, April, 1877.

+ Nature, February 22, 1877.

paragraphs of semi-scientific serials. The discovery in question relates to the preservation of iron from rusting in the atmosphere or in water exposed to the air. Rust, as every tyro in chemistry knows, is produced by the oxidation of iron, which, combining with the oxygen of the air, loses its metallic condition and appearance, and acquires totally different properties. But there are three oxides of iron, differing in the proportions of oxygen and iron contained, and differing also in their chemical properties. Upon this latter fact is based the invention of Professor Barff, the chemist of the Royal Academy, and author of a well-known and widely used text-book of chemistry. The first of the oxides of iron contains one equivalent of oxygen to one of iron; the second—the common "rust” of ironcontains three of oxygen to two of iron; the third, or magnetic oxide, four of oxygen to three of iron. The two latter only are of importance. The magnetic oxide, as its name implies, acts towards the magnet just as a magnetic metal. It differs from the ordinary “rust” in being black, and usually intensely hard. The natural "loadstones” consist of pieces of this substance. Professor Barff's process for preserving iron consists essentially in covering the iron with a thin coating of the magnetic oxide. To accomplish this the pieces of the metal are exposed to superheated steam, at a temperature considerably under a red heat. The crust produced is dark, hard, tough, not easily separable from the metal, and not liable to break off in flakes. The substitution of this species of “rust” for the ordinary red rust might not at first seem any advantage; but as the magnetic oxide does not appear to have any tendency to change in the air, and as it protects the surface of the iron from the action of the atmosphere, the importance of this very simple discovery can hardly be overrated. We shall heartily welcome an invention which promises fair to protect from destruction not only household utensils, technical appliances, and engineering structures, but also the sheathing of our iron and steel-plated vessels.

A propos of rust, it appears that the carbonic acid of the air, and of water exposed to the air, plays an important part in the production of common rust. For if a strip of clean iron be placed in water to which a little caustic alkali has been added, no rusting takes place. Hence the use of keeping bright iron objects in lime. The oxide of iron, especially when wet, takes up carbonic acid from the air, forming a carbonate of iron, and the carbonate readily parts with carbonic acid under the influence of heat. But no such interchange takes place in the case of the magnetic oxide, so that the latter does not spread and eat into the iron after the manner of rust.

The study of the preservation of meat from putrefaction affords scope for much ingenuity on the part of chemists. Quite recently the bisulphide of carbon has been applied to this purpose. Its application, however, can scarcely be regarded as successful, for though the protection against putrefaction appears to be complete, the persistence of the extremely unpleasant odour of the bisulphide will prevent its coming into use for food. Zöller has recently described to the Chemical Society of Berlin some experiments made with this substance upon considerable quantities of meat, and upon various fruits and esculent vegetables. A very few drops of this powerful antiseptic were sufficient to ensure complete preservation, and to procure the destruction of putrefactive germs. The fruit and vegetables lost their unpleasant odour upon a brief exposure to the air; but the meat, even after roasting, retained an unmistakeable taint from the minute quantity of bisulphide which still remained. Hugo Schiff has applied these valuable antiseptic properties in a different direction. He observed that the cocoons of silk-worms killed by the poisonous vapour of the bisulphide of carbon did not putrefy. He has kept without putrefaction, since 1869, the bodies of some pigs, and of a small lizard, by introducing into the vessels in which they were contained small quantities of the substance.

Mr. Keates has recently described, in the Chemical News, another use for the bisulphide of carbon. He proposes to burn it in an ordinary spirit lamp, in order to produce sulphurous acid gas for disinfecting purposes. He considers this a superior method of preparing the disinfectant to the usual method of burning sulphur.

A monosulphide of carbon is now prepared from the bisulphide by digesting in it metallic iron for a considerable time. The new substance is a reddish-brown powder. Whether it will prove as useful a substance in technological chemistry as the bisulphide, is scarcely probable.

Scarcely a month passes but some new form of adulteration is brought to light. Recently we have seen a flood of paragraphs in

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