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ly dried by means of blotting-paper and placed under the scope, the Nicols being crossed, it simply produces the effect of causing the field to become coloured with some geneous tint. But after the expiration of three or four tes the molecular change begins to be rendered apparent : circumference of the field by a rapid augmentation of the izing effect; in another moment it commences to dart across eld in all directions, the brilliantly coloured rays being ered with offshoots, reminding one of the rays of crystalammonium chloride. This beautiful effect continues until, s than ten minutes after the removal of the crystal from the er liquor, the rearrangement of the molecules has become neral that light is no longer able to penetrate, and the il becomes completely opaque. Messrs. Wells and Wheeler also attempted to prepare the analogous compounds conig iodine, but have not yet obtained them in a condition re or well crystallized as the salts described above.

IE additions to the Zoological Society's Gardens during the week include a white-fronted lemur (Lemur albifrons) Madagascar, presented by Mr. M. C. Parker; a brown chin (Cebus fatuellus 8) from Brazil, presented by Mr. e Tudor Johnson; a large-eared fox (Otocyon megalotis) Mashonoland, South Africa, presented by Mr. B. B. Weil ; black-backed jackals (Canis mesomelas) from South Africa, ented by Capt. Ralph H. Carr-Ellison; a common fox ris vulpes) from Arabia, presented by Miss Morgan; a beater's cockatoo (Cacatua leadbeateri) from Australia, preed by Lieut.-Colonel Warton; a Rhesus monkey (Macacus us) from India, deposited.

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The comet presented the appearance of a nebulosity about I' in diameter, diffuse at the edges, and brighter towards the centre, but without a well-defined nucleus. Its brightness was about that of a star of eleventh magnitude.

NOVA AURIGE.-Nova Auriga has again increased in magnitude, observations showing that visibly it is 8.5, while photo. graphically it is three magnitudes fainter.

ASTRONOMY AT COLUMBIA COLLEGE, U.S.A.-The latest number of the bulletin issued by this college informs us that with the consent of the governing body of the New York Hospital and the college trustees, a new but small observatory which is at present being constructed by Wauschaff, at Berlin, is about to be erected on the site Bloomingdale. The instrument, is a zenith telescope, and it is one of a pair which is going to be used for observations to obtain accurate determinations of the

variations of terrestrial latitudes. The other instrument, by order of the Italian government, is going to be mounted at the Royal Observatory of Capodimonte. Both instruments will soon be, if not already, in working order; the observers in America are Prof. Rees and Mr. Jacoby, while M. Higola will undertake the Italian observations.

The library of this college has been recently very much increased by the purchase of the fine library of astronomical and physical works belonging to Mr. Struve, former director of the Pulkowa observatory. This addition amounts to no less than 4361 bound and unbound books, together with 3056 pamphlets. COMPANION TO THE OBSERVATORY FOR 1893.-This annual Companion for the coming year is very similar to the one last published. Mr. Denning gives a list of the principal meteor showers deduced from recent observations, while ephemerides for the planets, together with their satellites, are also inserted. Solar observers will find the ephemeris given on page 22 very useful, this table giving the position-angle of the sun's axis, and the heliographic latitudes and longitudes of the centre of his disc. In addition to several other handy tables and ephemerides, the times of minima of variable stars not of the Algol type, variable stars of the Algol type, maxima and minima of variable stars, and finally a table of double stars are also included.

ing to the extremely bad weather, observations of this comet e not been numerous, but from all accounts not much change taken place in the general appearance, except that the tral nucleus seems to possess two small tails, which extend ards the ragged edge of the exterior portion.

COMET BROOKS (NOVEMBER 20, 1892).-Last week the only emeris of this comet at hand was one showing its position ry fourth day, but Prof. Kreutz has now communicated to nomische Nachrichten, No. 3132, a daily ephemeris, from ch the following is extracted :

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m the column showing the brightnesses it will be seen that onsiderable increase in this comet is taking place. The het will be easily found by the fact that it lies in the progation of a line joining 8 and 7 Bootis (December 18) at a ance equal to that between those two stars.

GEOGRAPHICAL NOTES.

MAJOR THYS, who has recently returned from the Congo Free State, reports that the railway from Matadi to Stanley Pool is progressing rapidly. The works are practically completed for only 14 kilometers out of the 400, but this includes the most difficult region, including the greater part of the ascent to the plateau. In a few months it is hoped that 40 kilometers will be completed, and the malarial coast-belt can then be traversed rapidly, obviating a serious risk to the health of travellers to the Upper Congo.

WE are pleased to find that the Manchester Geographical Society has published the concluding part of the seventh volume of its Journal although, as we had occasion to remark on the appearance of the previous part, it is greatly to be regretted that the people of Manchester do not take a greater interest in a Society which is one they have reason to be proud of. It is, we are convinced, solely to this want of local apprecia tion that the Journal has to be issued so far behind its proper date as to impair the usefulness of its contents. In the current number there is an interesting paper on Japan by Mr. W. M. Steinthal.

MR. G. A. CRAIG has, we understand, resigned the secretaryship of the Liverpool Geographical Society on account of ill

health.

THE Scottish Geographical Magazine for this month contains a paper by Captain Lugard, entitled "Characteristics of African

Travel." The Society presented Capt. Lugard with its silver medal and an honorary diploma of Fellowship. A similar award has been made to Mr. Joseph Thomson in recognition of his services to Geography in Africa.

DR. J. TROLL, an Austrian explorer, is at present engaged in a journey through Central Asia. He reached Samarkand in the end of October. Thence he proposes to pass through Russian and Chinese Turkestan and Mongolia, intending to return by Pekin and Shanghai. In the course of his journey he hopes to visit the ruined city of Karakoram, the ancient capital of Jenghiz Khan.

A RAILWAY has recently been opened from Wiborg, in Finland, to the Imatra Falls, thus bringing the finest rapids in Europe within six hours of St. Petersburg. Hitherto the falls have been reached by canal-steamer and coach, the journey occupying not much less than twelve hours.

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THE DESTRUCTION OF IMMATURE FISH.

MR. ERNEST W. L. HOLT contributes to the new number of the Marine Biological Association's Journal another very interesting paper on the results of his North Sea Investigations. He has much to say as to the destruction of immature fish in the North Sea, and makes the following observations on proposed remedial measures :

It will be admitted that the continued destruction of large num

bers of valuable fish before they have had a chance of reproducing their species can only result in increased deterioration of the industry, and that some measures must be taken to put a stop to it. unless we are prepared, and able, by artificial propagation to restock the sea as fast as we deplete it. Briefly the various proposals that have been put forward fall under three headings, viz. closure of grounds frequented by small fish, restriction of sale of undersized fish, and enlargement or alteration of mesh. We have seen that some of the smack-owners have adopted the eminently practical method of forbidding their boats to fish where they are likely to catch much small stuff; but the buyers, though as loud as any in their outcry, do not appear inclined to avail themselves of their undoubted power to check the evil. The proposals for legislative action have been so much discussed of late that I need only advert to such as affect the North Sea district.

It is a matter of common knowledge that the bulk of the destruction by deep-sea trawlers takes place on the eastern grounds, to which I have alluded elsewhere; and since these lie wholly or in part outside the three-mile limit, it has been proposed that they shall be closed to trawling by international agreement. Whether such agreement could ever be arrived at is questionable and if it were, it is not likely that the ensuing legislation could be easily enforced. The great extent of the grounds would involve an enormous and costly Marine Police force, of mixed nationality; and even were such a body much more efficient than one has any reason to expect, there might be considerable difficulty in adequately watching grounds which extend in some cases over fifty miles from shore. Indeed, on our own coasts and elsewhere the success with which legislation limited to the territorial area has hitherto been enforced is hardly such as to encourage us to extend the principle to the open sea.

The various standards of size which have been advocated, in proposals for prohibiting the sale or possession of undersized fish, differ according as the subject has been treated with regard to the marketable qualities of the fish, or to its powers of reproduction; and it may be assumed, I suppose, without argument that the latter is the more rational method of treatment. it may be as well to recapitulate the sizes proposed at the Fishery Conference at Fishmongers' Hall last February, since they may be taken to represent the most recent trade opinion on the subject.

Still

They are for turbot and brill twelve inches, for soles and lemon sole (Pleuronectes microcephalus) ten inches, and for plaice eleven inches. How far they fall short of the biological limits, at least for the North Sea district, can be judged by comparing them with the table of sizes on p. 384 of the Journal; and, indeed, I may remark that the prohibition of the sale of

turbot and brill under twelve inches in length is rather of supererogation, since the number of smaller fish species that come to market, at all events at Grimsby, is c insignificant.

The benefit to be expected from any measure of pr depends of course on the vitality of the fish, and generally asserted that the bulk of the small fish tra these eastern grounds would not survive if returned. X experience leads me to believe that this view is correct as the present system of long hauls is maintained. He must seek for such a limit as will render the grounds m quented by these small fish unprofitable to the fisherme any less limit would only involve an infinitely greater v takes place at present), and in doing so it is necessary! at the general conditions of this fishery.

Exclusive of less important forms, the species chiefly are plaice, turbot, and soles. The plaice, on most groz not exceed a length of fifteen inches, and are mostly le thirteen inches in length. The turbot are fairly abundan as I have already shown, almost all immature; soles are sa It is only the certainty of being able to fill up with sma that induces the fishermen to cross to the eastern side, s soles and turbot would not nearly pay his expenses by selves. Now I am confident that if the Conference eleven inches for plaice were enforced, there would enough saleable fish left to make the grounds worth whereas if it were raised to fifteen or even fourteen ince

grounds would assuredly be left alone; and although sva be below the biological limit, I believe the practical d our huge fleets of such a magnificent nursery for your would be in itself a sufficient protection for the species rough patches of ground, practically surrounded by are ing only small fish, abound with only large fish; the still be accessible to fishermen, whereas in any scheme: graphical restriction it would hardly be possible to exem Moreover the restriction of size would probably do asc the destruction of small plaice by shrimp or sole-traws the fish are not injured by being caught in these nets, and. saleable2 would probably be returned.

For turbot, brill, and sole I would advocate the adap the biological standards. They are all rather hardy f it appears that immature brill and such immature turbota found on our own coasts are chiefly caught on certam where the intricate nature of the ground renders short necessity, so that they could be returned to the sea in go dition, as indeed the smaller of them usually are at pre many fishermen. With regard to soles, I do not think that undersized fish are caught by deep-sea trawlers, and e tution of a size limit for the present prohibition of the fish-trawl in the Humber would do away with the and law which is not enforced. There is a strong feeling : inshore fishermen that the bye-law alluded to is unequal operation, since it offers no check to the destruction of on off-shore grounds, only accessible to large boats. Eregulation as to the size of fish landed is perhaps prefera one based solely on territorial conditions somewhat in understood.

An objection which I have heard urged against any for keeping our trawlers off the eastern grounds is summer sole trade in the North Sea would thereby be left e in the hands of foreigners. I think that this is, perhaps overstating the case, but anyhow I cannot see that it any excuse for the present enormous destruction of smal and turbot, whilst it is at least possible that the abstention own fleet from these grounds in the summer would res corresponding increase in the number of soles in the lo where that species congregates in the winter months knowledge of the migrations of soles, but the Great Silver equidistant from the Humber and the nearest eastern and as it is the nearest point at which similar physical co can be attained, it does not seem improbable that the supply of soles in the Pit is in part recruited from the c of the North Sea.

1 Owing to the great mass of fish caught in a single haul, I consid possible to hold this view without throwing any doubt on the v results obtained by my friend Dr. Fulton in his experiments of t of trawled fish (Report S F. B., 1891).

2 The possession, as well as the sale, should be prohibited, to g the possible danger of small fish being utilized as manure when th is also a farmer in a small way.

3 The small soles caught on the Dogger and on the Dowerg solanettes (Solea minuta).

Another objection is that boats of British nationality are not the only ones engaged in the small fish trade, and it is true that during the summer months a number of German, Dutch, and Danish boats are occupied in catching small plaice. But they are all of small tonnage, some of them only open boats; and I understand that from the manner in which the trawl is handled by German and Danish boats no injury is done to the anmarketable fish, whilst the saleable part of the catch appears to be exported chiefly to London. Hence the proposed measures of prohibition would give no advantage to these nations. The German steam trawlers, according to my information, do not molest the small plaice at all. Of the proceedings of the Dutch bombs I have little knowledge, but from the small size of their gear, their share in the destruction cannot be a very arge one. Foreign caught fish, except Norwegian salmon and mackerel and Dutch soles, including only a small percentage of mandersized fish, rarely come to the Grimsby market, but on two Occasions large consignments of small plaice, comprising, as I compute, some 31,000 fish, were sent from Denmark, and recently a consignment of turbot has arrived from Norway. These last fish were about 300 in number, all undersized, viz. from 9 to 17 inches, whilst 4 were only from 8 to 9 inches. This is the only instance which has come under my notice of any considerable number of turbot less than 12 inches being present in the market, and, as we have seen, our own fishermen were not concerned in it.

The last and perhaps the most important objection arises from the difficulty in allowing for that variation in the size of fish of the same species on different parts of our own coast to which Mr. Calderwood alluded in the last number of the Journal, p. 208. The impossibility of utilizing a uniform size limit for all districts sufficiently exemplified by the limit of 11 inches for the plaice proposed by the Conference of last February, which was the result of a compromise between the trade representatives of the North Sea and south and west coast districts. While perhaps unnecessarily high for the Plymouth district, we have seen that it is altogether too small for the North Sea. difficulty of having different limits, of local application, will only be felt at such a central port or market as London, to which fish are brought, whether by rail or sea, from all districts, but with proper organization the obstacle does not seem insuperable. It is conceivable that the law might be evaded by running cutters from boats fishing in one district to the parts of another, where the limit was lower, but it is little likely that the firms which are in a position to undertake them, would lend themselves to such operations. There is not the slightest reason to apprehend a general conspiracy of evasion amongst the fishermen, and the boats which respected the law would form a more efficient police than all the cruisers in the navy, so far as one may judge by the conditions on the Scotch coast, where convictions of trawlers for infringement of the territorial restriction are frequently secured by the evidence of local line fishermen.

the flat-fish render it impossible to deal with the whole question by restrictions of mesh alone.

The last matter with which I have to deal is the destruction of very small fish by shove-net and shrimp "seines." If it were only possible to induce the men to cull out the small fish in the water they would do no harm at all, and practically I suppose that, as matters are, they do not greatly injure any species of known value except the plaice, although the small number of sole, turbot, and brill destroyed may represent, from the relative scarcity of these species, a more considerable injury than one would suppose. When fishing by day the shove-net men usually return the fish to the sea, but by night this is impossible, and the seine men do not seem to make any effort in that direction either by day or night.

It is a difficult question to deal with, since the shrimp appears to be almost a necessity to some people; at the same time the small plaice which are destroyed must represent an infinitely greater value than the shrimps. If hatcheries were established, and young turbot, brill, sole, and plaice were enlarged after they had been reared through the delicate larval and metamorphosing stages, it is reasonable to suppose that they would be conveyed or would find their way to the sandy margins, which seem best adapted to the succeeding stages of their life-history, only to fall into the net of the shrimper.

I should say that to prohibit the use of any sort of shore shrimp nets during night-time would be a beneficial measure, but there is perhaps sufficient reason for abolishing the industry altogether. Those engaged in it might be sufficiently compensated at a moderate expenditure, if indeed it be not contrary to public policy to admit the existence of a vested interest in an occupation which is essentially injurious to industries affecting a much greater section of the community.

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The IN a small pamphlet of thirty pages, written and published by Mr. T. K. Dallmeyer, the author brings together the various notices bearing on the subject of his new telephotographic lens that have appeared during the last twelve months. He also gives an account of the "simple" and "compound telephotographic lens, with general instructions for their use, including tables of their properties, and a table showing the diameters of circles of illumination necessary to cover the various sized plates used at the present day.

I must leave to others, who are acquainted with the local conditions, to decide whether the imposition of a size limit is desirable in other districts, but for the North Sea I have not the slightest hesitation in recommending this method of legislation, in the terms I have proposed above, as cheaper and likely to be infinitely more efficacious than any other that can be devised in maintaining the supply of the more important kinds of flat-fish. need hardly observe that its application to the halibut, which < chiefly a line fish, could not fail to be beneficial to that species, ince there is no question but that fish caught on the hook will Sually survive if returned; but I do not think that the limit eed be as high as the biological one, owing to the difference n the conditions of the trawl and line fisheries.

I am not prepared to enter at present into the question of esh legislation, beyond pointing out that it appears to be the nly method by which the destruction of immature round fish, otably haddock and whiting, can be checked, since these species re fatally injured by being caught in the trawl, and would not rvive if returned. Any great enlargement of the mesh does ot appear advisable, since it would afford an opportunity of cape to the mature sole, of which that active species would be tremely likely to avail itself. The remedy seems to lie rather an alteration of the arrangement of the meshes in the codds, so as to prevent them from closing. On this subject I have en making investigations, but they are not yet sufficiently mplete to yield reliable deductions. It is sufficiently evident, has often been pointed out, that the great breadth of some of • Except fish with air-bladders, caught at considerable depths.

The telephotographic lens is, we may say, the latest advance made in the science of optics as applied to photography. By it we are now able to obtain large pictures of animate things situated at long distances with short exposure. In this invention Mr. Dallmeyer has produced a useful, and what may prove a valuable, instrument, and he has opened up quite a new horizon which will not suffer from lack of workers.

Hitherto the principle involved in the apparatus for the production of large images consisted first in obtaining the primary image, and second, in subjecting this image to the process of enlargement. To obtain the former a concave mirror, or more generally double convex lens, has been employed, while the subsequent magnification has been produced by placing a secondary magnifier or second positive lens behind the plane of the primary image.

This method, except in the case of astronomical work, has not been, we may say, popularly used, for the cumbrousness of the apparatus required, and the length of time necessary for exposure have quite prohibited its use for anything but inanimate subjects.

It is well known that the focal length of a lens is measured for practical purposes from the principal plane passing through one of the nodal points nearest the principal focal plane to that plane: in most lens-constructions this nodal point lies within the lensmount. Now it will be seen that if this nodal point could be thrown in front of the lens, that is, on that side away from the focus, the focal length, if measured from the lens, would be shorter. This is exactly what Mr. Dallmeyer has done. In the simple telephotographic lens the anterior element, which is of large aperture and short focus, is a positive lens, while the pos terior is negative, and of a fractional part of the focal length of the former lens. A diagram showing the lenses in position and the path of a ray of light remind one at first sight of the principle of the Galilean telescope, with this difference, that the rays emerging are not divergent, but convergent. In the construction

under consideration the size of the image thrown on the screen can be varied at will by simply altering the distance between the elements, but the further the lens is from the focussing screen, the more will be the time of exposure.

With such a lens as this Mr. Dallmeyer has taken many excellent pictures, but perhaps the best idea of its properties will be gathered from the facts obtained by photographing-by means of two cameras, one supplied with a "long focus landscape lens," and the other with the "new telephotographic lens' the flame of an oil lamp placed at a distance of 20 feet. With equal extensions of the camera the image of the flame given by the new lens was five times greater than that by the other.

In the compound lens the anterior element before referred to is here replaced by a complete portrait lens, while a negative symmetrical combination takes the place of the posterior element. This lens may be said to be more perfect than the simple lens, Mr. Dallmeyer having been able to introduce considerable improvement in the construction.

Some excellent work done with this lens has been exhibited by Messrs. F. Mackenzie and Annan at the Camera Club. The pictures represented a building at a distance of 500 yards. The first, taken with an ordinary rapid rectilinear lens with an extension of 14 inches, gave the house as of an inch long. The second-with the compound tele-photo lens, extension 9 inches from the back lens-gave 2 inches as the size of the house, while the third, with 30 inches' extension, gave the house as 6 inches. Although these numbers can give one a very good idea of what this new lens can accomplish, yet the direct copies from photographs inserted in the pamphlet under consideration convey a more vivid impression.

There is no doubt that this lens will find some very valuable applications, that of astronomical photography not being the least of them, for every one knows the great advantage a short telescope has over a long one if the degree of magnification in both are equal. W.

ARBORESCENT FROST PATTERNS.

WE have received the following letters with regard to

arborescent frost patterns, to which Prof. Meldola called attention in last week's NATURE:

I AM very glad that Prof. Meldola has called attention to the curved figures of frozen mud (of which the specimens on December 4 were unusually fine), because I hope that some one will explain why the sexangular crystallization which is universal in snow, and general in water, is exchanged both on windows and on muddy pavements for curves. Probably I ought to know all about it, but I cannot remember seeing an explanation, and shall be obliged by reference to one, which will probably be of interest to others besides G. J. SYMONS.

62, Camden-square, London, N.W.

THE interesting "fronds" of muddy ice observed by Prof. Meldola (p. 126) are not very uncommon on the pavements in these "Northern Heights." I saw them on the date which he named, and have more than once studied them. I then noticed that the "interstitial" pavement seemed partly cleared of mud, as if the water had drawn this towards the groups of crystals. The mode of formation recalled to my mind certain phenomena in crystal building within rocks, and I suspect the mud has its influence. Indeed, it seems to me very probable that all these "dendritic" growths of crystals are the results of "impeded" or "constrained" crystallization, to some of which I have called attention in noticing a structure in the Charnwood syenite (Quart. Jour. Geol. Soc., 1891, p. 101). On this point Prof. Sollas makes some important remarks in his well-known paper on the Wicklow granites. T. G. BONNEY.

THE beautiful curved forms assumed by the ice on the paving flags last Sunday were very noticeable in this neighbourhood and Hampstead as well as in other parts of London. What I observed were not quite like those described and figured by Prof. Meldola, but resembled rather the scrolls and volutes which are frequently used in decorative art. The finest piece that I saw was in this square, where several of these scrolls radiated from a central point, and spread over several feet of the pavement. A friend, Mr. E. Swain, observed that where one of these scrolls came upon a puddle of clear water the crystals were continued in a straight line. Such forms are not at all unusual in the freezing of muddy water, and at the present moment the puddles in the road opposite my house are

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the metal will present itself in the form of curved crystals, f the term be allowable. A pretty spray of gold of this character is figured in the report of my lecture "On the crystallization of silver, gold and other metals," in the proceedings of the Royal Institution, vi., 428. If a piece of cuprous oxide be immersed in a solution of nitrate of silver, there shoot from its surface thin threads of silver, which, after proceeding straight forward for a while, suddenly turn at an angle of 120 or 60%, and make perhaps many other deviations: but sometimes these threads, threads that branch from them are curved likewise. A maginstead of being straight, are curved; and in that case the fied drawing of such a formation is given herewith. These strange departures from the usual rectilinear course of crystal formation are very curious, and deserve more study than has hitherto been given them. J. H. GLADSTONE.

17, Pembridge-square, December 10. PROF. MELDOLA's letter (p. 125) has been interesting to me, as I noted a striking and similar phenomenon here on Thursday, December 8, in the forenoon. The trottoirs of several streets (east, west, north and south) were covered all over with beautiful patterns, somewhat different from Prof. Meldola's illustration, there being innumerable dark, broad, sharply-contoured leaf-like patches, distant several inches from each other, and connected by finely curved and branched tendril-like stalks Foggy, with a faint north breeze. I should presume the "leaves" were due to sparse drops of sleet fallen during the night. Freiburg, Badenia, December 10. D. WETTERHAN.

THE graceful arborescent frost patterns described by Prof. Meldola in last week's NATURE were very conspicuous on the foot-bridge by the side of Charing Cross railway bridge, on the same morning, this being a situation still more exposed to the wind which he mentions as the probable cause. December 12.

J. T. RICHARDS.

I OBSERVED the same phenomenon as Prof. Meldola describes in NATURE of December 8, on the same date, December 4, ca pavements in Cheltenham, about 10.45 a.m.; after mid-day they had gone. I saw the patterns on pavements running north and south, as well as east and west. They were most exquisite; some like the illustration, others much more minute; but always in a connected design over the whole flag. They had all the appearance of fossil vegetation. I never saw anything of the kind before. J. J. ARMITAGE

December 13.

MR. A. W. BENNETT and Mr. E. L. Garbett have also sent communications corroborating the phenomenon observed by Prof. Meldola. The former attributes it to "defoliation of the stones as the result of weathering or wear."

THE MAKING OF RIFLES.

Ta recent meeting of the Institution of Civil Engineers, Mr. John Righy, superintendent, Enfield Factory, read an ineresting paper on the manufacture of small arms. We reprouce from the abstract printed for the Institution Mr. Kigby's acid account of the various processes of manufacture of the omponents of the Lee-Metford Mark I. magazine-rifle, of o 303 nch bore, the weapon adopted for the British Army-an acount which he prefaced with a general description of the Enfield Factory.

The most important part of a rifle was the barrel, which had ways engaged the special attention of gun-makers. Up to the ime of the Crimean War, it was, for the bulk of British troops, comparatively rude tube of iron, lap-welded under rolls and apering externally, with a cylindrical bore of about inch iameter. The barrel of the present day was a steel tube of accurate workmanship, only inch bore, almost perfectly true nd straight, rifled to inch, and so closely inspected that the xistence of the most minute grey or seam in the bore, requiring a ighly-practised eye to detect it, was sufficient to condemn it. The material used was produced either by the Siemens-Martin or he crucible process of manufacture, and was supplied to Enfield as a solid round bar 1 inch diameter and 15 inches long. After severe testing, this bar was passed through a rolling mill to draw t to its full length: it was then taken to the forge, the swell at the breech-end was stamped to the required shape by a steamhammer, and afterwards straightened cold. The next step was to submit the bar, without annealing, to the turning and trilling-machines. The latter were horizontal, the drills operating rom each end. In the process of drilling, the barrel revolved it nearly 1,000 revolutions a minute against half-round bits held lat down, a capillary tube, of brass, supplying a soap-and-oil mulsion, at a pressure of 80 lb. to the square inch, to wash out he swarth and cool the cutting-edge. The drills advancing from ach end continued boring until a small disk about 1 inch liameter broke out, and the two holes met. The tendency of the drills to follow the line of axis of a revolving bar was one of those curious occurrences in practical mechanics which night be accounted for after observation, but which no one would predict. Occasionally, through some defect in the steel, adrili wandered from the axial line; in this case the barrel was aken from the machine and reset sufficiently to bring the hole true again. To test its truth, a ray of light was made to lluminate the flat bottom of the hole while the barrel slowly revolved. It was very rarely that a barrel was rendered waste from bad drilling. Kough-boring followed with a three-edged bit, the blade being about 4 inches long. The rough external turning was effected in self-acting lathes, which gave the required curved taper. Three or four cutters acted simultaneously, each producing a long cutting that attested the quality of the metal of the barrel. The operation of barrel-setting followed. Previous to rough-turning, the barrels were fairly straight internally, but the removal of the metal caused slight inequalities which were tested by the eye of the barrel-setter, and corrected by transverse blows. This constituted skilled labour of a peculiar character, and was performed by young men of good sight, who were specially trained for the purpose. After niddle life the eye generally lost some of the quality necessary or this work, and it was rare to find a man excel in it after hat period. Many mechanical devices had been contrived to upersede the simple ray of light laid, as if it were a straight edge, long the surface of the bore; but the eye still remained the rbiter of straightness and could be relied on for very accurate esults. The construction of the barrel was completed by the mportant operation of rifling. In British small-arm factories he system was followed of planing out each groove separately vith a hooked cutter, and had been brought almost to perfection. n Continental and American factories the grooves were ploughed but by cutters, with several cutting or knife-edges set at an angle nd following one another in the manner of a single-cut file or loat. Similar machines had been tried at Enfield, but did not ive as smooth a cut as the slower-moving, single-tooth machines. A few passes of a lead lap, fed with fine emery, removed any urr that might remain, and completed the polish; a cylindrial lap, spinning rapidly, was then passed through, and gave the The limits of gauging were from

nal finish to the barrels.

303 to 0 305 inch.

Next in importance to the barrel was the mechanism of the reech, for which the material preferred was crucible cast-steel

of a mild character, but capable of being hardened in those parts exposed to the pressure of the bolt. The body was forged in two operations under the steam-hammer; it was then drilled and subjected to a long series of operations, in the course of which the end was recessed to receive the screwed end of the barrel, and the corresponding thread in the recess was milled out in a specially-contrived machine, which insured that the thread should always start in the same place relative to the gauged part of the body, a point of great importance. The bolt, also of crucible cast-steel, was forged under the steam-hammer. A special machine, invented at Enfield, was used to finish the bolt after shaping. After machining, the bolts, packed in wood charcoal in iron cases, were heated and hardened by immersion in oil. The temper of the handle was then reduced in a lead bath. The rest of the bolt was tempered straw-colour. The bolt-head was similarly hardened and tempered.

The other components of a complete rifle were mostly shaped by mills built up to the proposed profile, or by copy-milling machines. The process of drifting was used with good results at Enfield. All such slots or perforations as had parallel sides, and were not cylindrical, were so finished. The common practice in drifting was to push the drift, but at Enfield much better work was accomplished by pulling. It was found that used in this way drifts were very valuable for interchangeable work. The sides were cut with successive teeth, each slightly larger than the preceding one, and the whole length of the drift was drawn through. Emery wheels were also largely used at Enfield as a substitute for finish-milling and filing. The wheels ran under hoods connected with a pneumatic exhaust that carried away the heated particles of steel and grit. It was popularly supposed that a machine once adjusted to turn out a component of a certain size and shape was capable of reproducing such in large numbers, all absolutely identical. This was so far from being the case that no die, no drill, and no milling-cutter actually made two consecutive articles the same size. The wear of the cutters or dies proceeded slowly but surely, and it was only possible to produce in large numbers components of dimensions varying between a superior and an inferior limit. In smallarm manufacture a variation of about one two thousandth of an inch was about the amount tolerated, but it varied according to the size of the piece. A difference of diameter of one twothousandth of an inch in the sight axis-hole, and in the size of the pin or axis, would cause a serious misfit, whereas a similar difference in the measurement of the magazine, or of the recess in which it lay, would be quite immaterial. The operations of gauging, proving the barrel, and sighting, were successively described, as also the manufacture of the stock, which was of the wood known as Italian walnut, though largely grown in other countries. Among the smaller components, the screws were mentioned as being rapidly produced by the automatic screwmaking machines of Pratt and Whitney.

The Component Store received the various finished parts, which numbered 1591, or, including accessories, 1863, and issued them to the foreman of the assembling-shop. Theoretically, the assemblers should have nothing to do but to fit and screw them together, but in practice small adjustments were found necessary. The amount of correction was generally exceedingly small, and was done wherever possible with the aid of emery wheels. The completed arms were submitted to inspection, and then issued in cases of twenty each to the Weedon Government Store or elsewhere.

UNIVERSITY AND EDUCATIONAL
INTELLIGENCE.

CAMBRIDGE.-The General Board of Studies propose that, in view of the increased attention given to palæontology in the Geological Department, a Demonstrator in Palæozoology be appointed, whose stipend shall be paid out of the students' fees.

The Botanic Garden Syndicate report the completion of the fine range of plant-houses, which have for some years been in course of erection at a cost of some £6000. It is noteworthy that the expense has been kept within the estimate.

The Senate has determined to raise the fee for the Doctor's degree (including M. D. and Sc. D.) from £20 to £25. It has rejected the proposal to increase the annual dues of under. graduates from 17s. to £2, and of graduates from 175. to £1, which was put forth in view of the financial needs of the University, by the Fees Syndicate. The proposal to accept life

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