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wherever possible results have been found by rational rather than empirical methods. The design of a steam boiler, so far as strength is concerned, is a matter in which the designer has but small latitude. In this country he has generally to make the results of his calculations conform to the rules of the Board of Trade, or of Lloyd's Committee, or of both. Hence the book will be of greater service to the student than to the practical designer, although there is much in it which will appeal to the latter also.

Naturally much reference has been made to the Massachusetts Boiler Rules, which have been used as a model by many States and adopted bodily by others. It is of interest to note that, with certain exemptions, these rules provide that all boilers shall be inspected when installed and annually thereafter by the inspection department of the district police, under supervision of the chief inspector of boilers. In this country the periodic inspection of land boilers is left to the owner, who generally delegates the matter to his insurance company. If the boiler is not insured, periodic and competent inspection may, or may not, be carried out, and depends entirely on the owner's workmen or engineer.

The book is well illustrated and contains several fully worked out designs. These, and the methods of calculation, are of considerable interest and will be of service to engineers in this country who wish to acquaint themselves with up-to-date American practice in boiler design.

Mechanical Drawing, with Special Reference to the Needs of Mining Students. By J. Husband. Pp. 79. (London: Edward Arnold, 1915.) Price 38. net.

READERS of this excellent text-book will have a feeling of satisfaction that a piece of good work, evidently much needed, has been conceived and carried out in a thoroughly efficient manner. Teachers and students connected with mining and colliery engineering are much indebted to the author for putting at their disposal, in a convenient form, material which will specially appeal to them and will prove most helpful in the drawing classes and an incentive to study.

The course is progressive, beginning with some excellent advice on the selection and manipulation of drawing instruments. The well-executed drawings are fully and clearly detailed and dimensioned, and the descriptions are always suggestive in pointing out the leading features of a design, and are models of conciseness and lucidity.

The examples selected are welcome on account of their freshness, importance, and suitability. In order to give an idea of the scope of the work we may instance the plates on bolt and rivet fastenings; built-up work, such as stanchions, girders and pump quadrants; pedestals, shafts and axles for wagons and winding engines; mine cages and colliery tubs; haulage clips and safety hooks; mine pumps; pneumatic hammer drills.

We strongly recommend teachers of elementary machine drawing to consult this most useful manual.

LETTERS TO THE EDITOR.

[The Editor does not hold himself responsible for opinions expressed by his correspondents. Neither can he undertake to return, or to correspond with the writers of, rejected manuscripts intended for this or any other part of NATURE. No notice is taken of anonymous communications.]

The Use of Cotton for the Production of
Explosives.

WHILE in no way attempting to dispute the authority of the writer of the article on gun-cotton in NATURE of July 1, I should like to take the opportunity of expressing my surprise at the conclusions there reached. On general grounds one would anticipate that plant-products, such as cellulose and alcohols, could be prepared in any country, so long as plants grew; they stand in sharp distinction from metals and petrol, which are not of universal occurrence.

It scarcely seems likely that the suitability of cotton as the cellulose basis for certain explosives can be due entirely to chemical peculiarities, for although cotton is a typical cellulose it contains many impurities -mineral salts, dead protoplasm, cuticle, waxes. These cannot all be entirely removed in course of manufacture, and it is presumably their presence which necessitates the very careful blending employed in preparing cotton for nitration. It seems likely that the matter is one of physical properties, the thin-walled, hollow, pitted cylinders of the cotton hairs offering a large surface to reagents.

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But if this were the prime advantage of cotton, it is not one which need inhibit the use of other forms of cellulose for the making of "gun-cotton." Even the best cotton is by no means uniform from hair to hair, and the waste cotton used for nitration is still more irregular; consequently, it seems likely that an artificial cellulose might be made even more uniform than cotton. It would scarcely be possible to make such a product with the same ratio of surface to mass as is found in natural cotton hairs, but this ratio could at least be made constant, e.g. by dissolving the cellulose and squirting_thin threads of it, in the form of "artificial silk." The trade in these artificial silks is mainly Continental, and has been developing rapidly during the last ten years, so that there should be no lack of knowledge of the process in Germany.

Undoubtedly "gun-cotton" made in this way would be quite different from true gun-cotton. All values would have to be re-computed; the trajectory, with the sighting and timing, would be altered, and a great deal of extra work would be thrown on all concerned, but with all submission to the chemists, to whose domain this matter belongs, I venture to think that it may be possible to turn out perfectly uniform "guncotton " with cellulose derived from plants other than cotton. The question of cost is immaterial in the circumstances, and although it cannot be doubted that the cutting off of Germany's cotton supplies would hinder the German guns, yet it seems likely that a fairly effective substitute might be devised by the nation of technologists.

Carlyle may be quoted in this connection. "Interrupted Commerce and the British Navy shut us out from saltpetre; and without saltpetre there is no gunpowder. Republican Science again sits meditative. What of saltpetre is essential the Republic shall not want." W. LAWRENCE BALLS. Little Shelford, Cambridge, July 7.

I HAVE read not only with interest, but also, I hope, with some instruction to myself, the admirable letter from Mr. Balls which you have been kind enough to let me see. I am entirely in accord with him in his

view that as long as plants grow so long will cellulose be formed, and with this as a basis nitro-cotton can certainly be prepared. I do not wish to convey the idea that the reason why cotton waste is chosen for making nitro-cotton is its chemical idiosyncrasies, but rather that it is the most abundant and fairly uniform stuff which is available for practical use. Mr. Balls is quite right in thinking that the physical structure of cotton fibre has much to do with the applicability of cotton for making propulsive explosives, but this cuts both ways, because even cotton is troublesome in that those fibres tend to retain acid, which has to be removed by regulated boiling and washing. Hence the suggestion that an artificial "cotton might be used is well worth considering-dissolved and squirted cellulose being necessarily fairly uniform-and I agree with Mr. Balls that it would not only be possible but also tolerably easy to turn out perfectly uniform guncotton made this way.

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Nobody has denied from the beginning of the discussion which has taken place in the Press on the subject of cotton for explosives, that nitro-cotton can be prepared from any source of nature which can provide us with cellulose, but the issue is really rather different. It is impracticable for a factory accustomed to using a particular raw material so to alter its operations as to use another raw material without great delay, expense, and in this case much danger. The other difficulty has been mentioned by Mr. Balls, and is that of the artillerist who, given even a better nitrocotton than that to which he is accustomed, would have to learn his art all over again, and meanwhile it is of more advantage to his country that he should be sighting his gun in the manner to which he is accustomed. To use a homely expression, it is generally a mistake to swap horses in crossing a stream.

THE WRITER OF THE ARTICLE.

The Great Aurora of June 16, 1915. THERE have been comparatively few auroras here of late years. In that time we have passed through the aurora minimum. Lately, however, there have been distinct indications of an awakened activity in the frequent appearance of auroral glows and arches. But these were generally feeble, and at best showed very little in the way of streamers or other signs of activity.

The night of June 16 was very clear throughout, and gave us one of the finest displays of the aurora that I have seen. Before the moon set there was a very strong, low-lying arch in the north. This was not active, but its intensity seemed to suggest the possibilities of a great display.

At 15h. 30m. G.M.T. the arch was very low and flat, and extended a great distance towards the east and west. There were no streamers.

At 16h. 10m. there were no streamers, but there was considerable action underneath the arch in the way of brightening masses. At 16h. 50m. the arch was double in its eastern part, the upper portion extending to the lower part of Cassiopeia.

By 17h. 10m. the aurora was very brilliant and active, the arch having risen and spread all over the north, nearly as high as the pole. The lower part of the arch was broken with bright moving forms. A few minutes later the arch had risen above the pole, while below it there was very little auroral light except a few streamers. By 17h. 30m. the aurora had quietened down, and the great spasm, seemingly caused by the rising of the arch, had subsided, with the exception of some great bright masses in the north-west, where the remnants of the arch had drifted.

By 18h. 13m. a low, strong arch, slightly active,

had again formed in the north. The new arch soon rose and also became double.

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By 19h. 43m. the arch was breaking up, and very long streamers were ascending everywhere. 19h. 52m. quick waves of light were ascending towards the zenith, succeeding each other with remarkabl rapidity. These waves continued without intermission until dawn blotted them out about 21h. 5m.

After about 19h. 40m, the display rapidly increased in magnitude, and attained its maximum splendour at about 20h. 10m. or 15m., when it became too bewildering to describe. The whole heavens seemed alive with flickering and dancing light. The rapid waves of light and the streamers were ascending in all directions, even from the south, to a focus that appeared to be on or near the meridian and about 20 south of the zenith. (Its declination was roughly +23°.) This focal spot was occupied by some of the irregular luminous masses which were momentarily brightly illuminated by these waves. The streamers were no longer slender rays; they were now broad sheets of light along which the ascending waves raced with intense rapidity, giving them the appearance of flames rushing up from the horizon to and beyond the zenith. These quick light waves momentarily and brightly illuminated every object over which they passed. The sky was full of wisps and curved streaks of luminous matter over which the light waves took a sensible moment to pass. This produced a remarkable effect. As the light ran from end to end of them the rapid brightening seemed to give life and action to these streaks and produced in them a writhing and darting motion which they did not possess, for their real motion and change of form was quite sluggish. As late as 21h. 25m., when the sky was bright with dawn, some of the great bright masses were still visible in the north-west.

There was but little colour in the display at any time, though some of the streamers and masses assumed a slight pinkish tinge at about 19 hours. Efforts were made several times to form curtains at the bases of masses of streamers, but no regular curtains were actually formed.

Throughout the night I was photographing with the Bruce telescope. As frequently as possible notes were made of the progress of the aurora. At 20h. om. the sky was so brilliantly lighted that I was forced to close the exposure. The resulting negatives were badly fogged with the auroral light, which seemed to be more actinic than moonlight.

The present aurora was much like that of 1903, October 30 (see Astrophysical Journal, vol. xxxi.. p. 212), in its phenomena and its effects on the telegraph systems, but exceeded it in some respects.

From the newspaper accounts we learn that the aurora was visible over the greater part of the United States and Canada. It was strong even in California. A despatch to the Los Angeles Tribune of June 18. from Spokane (Washington), dated June 17, says :"Electrical currents caused by the aurora borealis almost stopped telegraph service in northern Idaho, Montana, and the Dakotas between midnight and I o'clock this morning. Up to 9 o'clock this morning the Western Union Telegraph Company reported interrupted service, but not to such a great extent as in the hour following midnight."

In the Chicago Tribune of June 18 a despatch from New York, dated June 17, says :

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"Across northern Idaho, Montana, and the Dakotas service virtually was suspended. Like unsatisfactory conditions prevailed on all the northern transcontinental lines.

"For several hours during the early morning cable communication via the Newfoundland cables of the Western Union was all but paralysed."

During the progress of the aurora, Mr. Frank Sullivan and Mr. E. P. Hubble, of this observatory, tried the wirless receiver here, with which time-signals are received from Arlington, Virginia, Mr. Sullivan at 14h. 45m., when the arch was strong but not active, and Mr. Hubble at 20h. om., when the greatest display occurred. They found in both cases that the static conditions were normal. Mr. Sullivan reports that it was unusually quiet. E. E. BARNARD.

Yerkes Observatory, Williams Bay,
Wisconsin, June 25.

The Magnetic Storm and Solar Disturbance of
June 17, 1915.

A CORRECTION is necessary for the value of 1' of arc displacement for the H.F., given in my letter published in NATURE of June 24. It should read, line 18 (I' = 4.0 × 10-5 C.G.S. units). There is also an ambiguity in the preceding line, in the use of the word displacement. The extreme values of the greatest oscillation in the H.F. about 4.15 p.m. amounted to 100', as stated, but the maximum displacement was 76', the value of the base line being 24'.

In his very interesting letter on this subject (NATURE, July 1), Dr. Chree mentions several dates on which sudden movements of the magnets occurred, which are presumably of cosmic origin. It may also be of interest to compare the state of the solar surface on these dates with these sudden movements. The first occurred at I p.m. on June 16. On this date the two sympathetic groups of spots, which I have associated with the magnetic storm of June 17, evinced considerable disturbance, the faculæ in the neighbourhood of these two groups, as also bright faculæ conjoined with two other groups nearer the E. limb, showing a decided drift towards the south. On June 18, as already described in my last letter, the whole of the region between these two groups was violently disturbed, and the faculæ, which must have been very bright to be visible in the middle regions of the sun, showed the same southerly drift. As this was visually the most disturbed region of the sun, and, moreover, it was near the heliographic position of the earth, it seemed most likely that this region was the one connected with the magnetic storm, if any such direct connection exists.

On June 14 a bright compact patch of faculæ appeared in the N.E. quadrant on the sun's limb, in which were a few small dots. This new disturbance continued to grow, until on June 21 it had developed into a fine group of large spots near the central meridian. Its mean approximate position was +17° latitude, and 356° longitude. This region was also much disturbed on June 19. Dr. Chree directs attention to the considerable magnetic disturbance which commenced at 3.10 p.m. on June 21 with a sudden movement of the H.F. magnet. Dr. Chree also mentions another sudden commencement on June 7 "of considerable size at a time when Father Cortie tells us the sun was almost free from spots." On that date there was only one group of very small spots at mean latitude +21° and longitude 1980, in a ring of faculæ. But I find on consulting our solar drawings that

M. Henroteau, the observer, has made the following note on the drawing of June 8, with regard to this group of very small spots: "The region of the spots seems very disturbed."

Finally, that quiet magnetic conditions show the twenty-seven day period is not inconsistent with, but would naturally follow from, successive synodic presentment earthwards of an undisturbed hemisphere of the sun. A. L. CORTIE.

Stonyhurst College Observatory, July 4.

Use of Tyrosine in Promoting Organic Growth.

I DESIRE to direct the attention of readers of NATURE to the influence of tyrosine in promoting the growth and multiplication of any organisms that may be found in tubes five to ten months after they have been hermetically sealed and sterilised, as described in "The Origin of Life," second edition, 1913, and NATURE of January 22, 1914.

The June number of the Proceedings of the Royal Society of Medicine contains an illustrated communication dealing with the effects of this powerful auxetic when used in the form of a 0.05 per cent. solution. Its influence was tested on a large number of tubes ripe for examination, containing five different kinds of experimental solutions (the constitution of which is given) by adding, with all necessary precautions, about twenty drops of the tyrosine solution to each tube when it was opened. The tubes were then reclosed and replaced in the incubator for three to four weeks. When the contents of these tubes were reexamined after such an interval a very considerable growth and multiplication of unmistakable organisms were found to have taken place, thus tending to disprove the two principal doubts that had been urged against the original experiments by showing (1) that what were found were not mere pseudo-organisms; or (2) organisms which had pre-existed in the solutions, and had been killed by the sterilising process. Photomicrographs of the organisms taken from the tubes before, as well as after, the addition of the tyrosine show its great influence in favouring the multiplication of bacteria, torulæ, and moulds.

I have quite lately heard from the brothers Mary (Institut de Biophysique, Paris) that they have been similarly successful in obtaining from some of their tubes, after the addition of tyrosine, plenty of budding torulæ, as well as delicate spore-bearing moulds, and that they are about to publish an account of their investigation.

The last number of the Proceedings of the Royal Society (B. 609) contains an interesting paper by Prof. Benjamin Moore and W. G. Evans, in which they describe and figure some simple pseudo-organisms, of a kind with which I am quite familiar, obtained from a limited number of tubes containing solutions apparently similar to some of those which I have used. I have prepared and examined more than a thousand of these tubes, and among them have found many barren series. A comparison of their illustrations with mine will show that they have hitherto met with totally different objects. It is true, however, that some of their finds, under the low magnification which they employ, have a superficial resemblance to matted or twisted hyphæ of moulds (see especially Figs. 1, 7, and II).

The simplest solution from which I have obtained different kinds of moulds, and which I can recommend to others, is one made from 10 per cent. solutions of iron sulphate and potassium ferrocyanide, in which one drop of the former and two of the latter are added to each 30 c.c. of distilled water. The iron stock

solution changes colour somewhat after a time, owing to oxidation of the ferrous salt, as Sir Wm. Ramsay tells me, and the moulds found in solutions prepared

from fresh stock fluids and from others one or two months old have been of a different kind. The remarkable mould of Cladosporium type referred to in a note to my paper was found in each of a series of tubes the solutions of which had been prepared from stock fluids one month old. An examination of the stock fluids themselves, even after three months, does not reveal moulds of any kind. H. CHARLTON BASTIAN.

Fairfield, Chesham Bois, Bucks, July 9.

Napoleon and the University of Pavia. THE following allusion to Napoleon having spared the University of Pavia in 1804 on account of the memory of the illustrious man of science, Spallanzani, who had been a professor there, is so interesting at the present time that I venture to bring it under the notice of readers of NATURE.

The passage is from Baron's "Life of Dr. Edward Jenner" (vol. ii., p. 35), which was published in 1838" He who flushed with victory and at the head of the revolutionary army of France had spared the University of Pavia out of respect to the genius of Spallanzani when the city itself was given up to plunder, proved that the claims of science were not forgotten amid the astonishing events which carried

him forward. to the highest pinnacle of ambition. His animosity to England had been shown in that vehement and decided manner which marked all his actions; yet there was one chord of sympathy unbroken which, when duly touched, showed that his intoxicating success had not raised his proud spirit beyond some of the calls of justice and humanity, and that he could still be moved by the peaceful arguments of truth and science."

Napoleon's conduct in regard to the ancient University of Pavia is in striking contrast to that of the Kaiser in regard to the University of Louvain. The Germans, in their own opinion, are pre-eminent in the subject of the history of medicine, and yet it has been reserved for Germans to destroy the University of van Helmont, the father of chemistry, of Vesalius, the father of anatomy, of Schwann, the originator of the cell-theory. Further comment seems unnecessary. D. FRASER HARRIS. Dalhousie University, Halifax, N.S., June 19,

A New Tsetse-Fly from Zululand.

THE Durban Museum has lately received from Mr. R. A. L. Brandon, the magistrate of Ubombo, Zululand, a tsetse-fly captured by him in the court-house at Ubombo, towards the end of March, which is very distinct from the ordinary Zululand species, Glossina pallidipes, Austen, and apparently belongs to an hitherto unknown form.

It is a member of the palpalis group, and seems most nearly related to G. tachnoides, Westw., but the markings on the abdomen are not so strong or so sharply defined, and the dorsum of the thorax is buff. It is a female, and measures 8 mm. in length, exclusive of proboscis. In honour of the captor it may be known as Glossina brandoni.

It is my intention to give a detailed description in the next number of the "Annals of the Durban Museum." E. C. CHUBB. (Curator).

Durban Museum, Natal, June 16.

MUNITION METALS.

N this article an attempt is made to compare briefly the resources of the Allies and the enemy countries in respect of metals which are regarded as essential for War purposes.

First in order of importance comes iron, the basis of the modern gun, armour-plate, armourpiercing projectile, shrapnel shell, high-explosive shell, and all the varieties of steel which find application in one way or another. Both sides have a sufficiency of iron ore and the accessories required for smelting, although the deposits in the enemy countries are inferior in quality to those possessed by the Allies. An illustration of this is furnished by a comparison of the amounts of acid and basic steel produced in Germany and Great Britain in 1913-the last year for which the complete figures are available. Germany's total steel production for that year was just under 19,000,000 tons, of which 96 per cent. was made in basic-lined furnaces; Great Britain's output was 7,663,000 tons, of which only 36 per cent. was made by the basic process. Both countries, however, imported considerable quantities of Swedish pig-iron, which is used for the manufacture of steels of the highest class, e.g., tool steels, and Great Britain also imported substantial amounts of Spanish hematite ore, which was smelted with the clay ironstone ores of the Cleveland district, which are low in iron, and contain, for the most part, more phosphorus than is compatible with the transformation of the resulting pig-iron into steel by any acid

process.

The production of open-hearth steel from pigiron and such steel provides the casing of the high-explosive shell and the shrapnel shell-demands, however, a second and very important metal, namely, manganese, which in the form of ferro-manganese or silico-spiegel is used not only to de-oxidise the fluid steel, but to leave from 0'5 to 10 per cent. manganese in the finished product. The chief producers of marketable manganese ore in order of importance are Russia, India, and the United States of America, which in 1913 furnished about 93 per cent. of the total quantity mined. The raw material is pyrolusite, a 'straight" manganese ore corresponding when pure to MnO2. The main supplies of pure ores, therefore, are in the Allied or neutral countries. In 1913 Germany imported about 670,000 tons, chiefly from Russia. The figures of her domestic production in 1913 are not available, but in 1912 her output was 90,980 tons, while that of AustriaHungary was 16,540 tons in 1913.

In spite of these figures there is no sufficient reason for concluding that the enemy countries will be greatly hampered even if all external sources of supply are shut off, as they probably are. Confining our attention to Germany, the predominant partner, it must be pointed out in the first place that 4,300,000 tons of her steel production in 1913 were exported, and that except in so far as Austria-Hungary and Turkey are concerned this excess would be available for her own

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munition needs if she could obtain sufficient man-high-speed tool steels. Rhodesia and New Caledonia ganese. In the second place, the last-named metal is relatively widespread and occurs in many minerals. It is only the limited demand and the abundant supply of high-grade ores to draw upon which have confined marketable ores to such products. The enemy countries will in all probability be able to supply their needs by mining lowergrade ores within their own territories, and their metallurgists will no doubt have been able to make the requisite changes in the technology of steel manufacture to meet the altered conditions-quite apart from any stores of pure ore that may have been accumulated before the outbreak of war, and apart from any substitutes that may have been discovered.

The case of nickel, however, is very different. It is an indispensable constituent of gun and armour-plate steel, and of the modern bullet and armour-piercing projectile. In all these instances its action is specific, and it is doubtful whether any satisfactory substitute is known. It is therefore a munition metal of the highest importance. The world's production of nickel in 1912 was about 26,500 metric tons (a metric ton equals 2204 lbs.). Of this, Canadian mines and smelters produced 85 per cent. in the form of a copper nickel matte (sulphide), 89 per cent. of which was refined in the United States and the remainder at Clydach in South Wales, with the production of the pure metals. New Caledonia supplied almost all the remaining ore required, this being shipped to Europe and smelted there. Judged by Canadian standards the Norwegian production of nickel was very small, the output in 1912 being only about 400 tons.

The position, therefore, is that fully 985 per cent. of the world's output of nickel ore was being produced in the Allied countries before the war broke out, and that the remainder was furnished by a neutral country. So far as Canada is concerned the situation was dominated by two companies, the International Nickel Co. and the Mond Nickel Co., while the production of nickel ore in New Caledonia was monopolised by two large French companies. The only nickel ores situated in the enemy countries are kupfernickel (NiAs), cloanthite (NiAs), and nickel glance (NiS2+ NiAs). Each of them can be worked for the production of nickel, but how inadequate a source of this metal they were may be judged from the imports of ore and metal into Germany in 1913. In the first six months she imported 6643 metric tons of ore and 3416 metric tons of metal. (It is to be noted, however, that her exports of the same metal were 2409 tons in the same year.) The Norwegian nickel production may still be available for Germany, but this is nothing like enough for her requirements, and apart from prewar stocks she will have to fall back on the abovementioned native ores to furnish the requisite quantity of this metal.

Scarcely less important than nickel is the metal chromium, which, though it finds no application in the pure state, is an essential constituent of armour-plate, armour-piercing projectiles, and

furnish between them the bulk of the principal chromium ore, chromite (an iron chromium oxide). Russia produces substantial amounts, while Greece and Asia Minor used to do so, though their output has diminished in recent years. It is more than likely that the requirements of the enemy countries are resulting in an increased output from the last-named countries, and it will be observed that even if Greece joins the Allies the Asia Minor supplies, which are sufficient, will still be open to the German and Austrian armament firms. Chromite is worked up into an alloy of iron and chromium (with or without carbon) known as ferro-chrome, and applied in this form to the production of the particular steel required.

All shells, whether shrapnel, high-explosive, or armour-piercing, are fitted with a copper band which serves a double purpose. It prevents contact between the shell and the gun-barrel, and, owing to its great ease of deformation under stress, accommodates itself to the very rapidly altering stresses set up in the tube after firing, making good contact with the rifling of the barrel, and thus preventing the rush of gas out of it in advance of the projectile. Before the war it was customary to use not pure copper, but an alloy containing a little zinc, as the material of the band, not because the zinc improved the properties of the copper, but because it was a cheaper metal, and a certain proportion of it could be used with only a slight sacrifice of ductility. Now that zinc. has become much more expensive than copper there is no object in doing this. Copper is also the main constituent of cartridge brass and shell fuses, Admiralty gun metals, and high-tension hydraulic bronzes, so that from the point of view of both branches of the service it is a most important munition metal.

Of the normal annual world's output of copper -about one million tons-the United States of America produced 55 per cent. in 1913. They

are by far the greatest producers of this metal. Next came Japan with 73 per cent., followed closely by Spain and Portugal, Mexico, Australasia, Russia, and Chile, each of which supplied between 5 and 4 per cent. Of the Allies Italy furnished o'16 per cent., Great Britain o'03 per cent., while France was a non-producer. Of the enemy countries Germany's output was 25 per cent., and that of Austria-Hungary 0'4 per cent. None of the belligerent countries except Japan supplied its needs from internal sources in 1913; all of them except Japan imported copper from the United States of America; in that year Germany took 137,000, France 71,400, Italy 18,500, Austria-Hungary about 17,000, and Great Britain 15,000 tons.

The Allies are able to take delivery of such copper as they need, thanks in the main to the British Navy, whereas the enemy countries have found it increasingly difficult to import this metal. The position probably is that they have succeeded in obtaining through neutral shipping and neutral countries more than is generally suspected, but nothing like enough for their war needs, more

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