Slike strani

he Museum of Science and Art, Edinburgh, is based upon tholomew's map of Edinburgh on the scale of 15 inches to ile, but the altitudes are taken point by point from the large n plans of the Ordnance Survey. The model is in many s original in its mode of construction. Its object is purely graphical, having been suggested by a leading citizen as a hod of showing the contrast between the circuitous roads frequent steep gradients of the old coaching days, and the ghter and more level lines of communication by which ern engineers have overcome the restraint of physical con


the same number of the Scottish Geographical Magazine is a paper on the Deserts of Atacama and Tarapaca, read e Society by Mrs. Lilly Grove, and some interesting notes outh Eastern Alaska by Prof. J. J. Stevenson, illustrated by


R. H. J. MACKINDER's third educational lecture for the 1 Geographical Society was given on Friday night, the ct being the belt of Steppe which traverses Asia from to east. He showed how the distinctive physical and tic conditions of the Steppe favoured the growth of dic nations, every man of whom was a member of the mobile cavalry force which ever existed. Pastoral purand marauding were natural to the Steppe peoples, and escent of their hordes on the settlements bordering the e were turning-points in the history of surrounding Reference to the successive periods of conquest by ythians, Huns, Turks, and Mongols showed the power of nomads on the affairs of other countries, and until the t of the Steppe-bred Cossacks no western power has ever d control of the central Asian plains.


LOWING on the death of Captain Stairs we have to record ath of his fellow-officer in the Emin relief expedition, Mr. Nelson. Mr. Nelson returned to Africa, and was in of the district of Kikuyu in Ibea, when he succumbed ittack of dysentery on December 26, 1892.


first general meeting for this year of the Institution of fechanical Engineers was held on Thursday and Friday s of last week, the 2nd and 3rd inst., in the theatre of titution of Civil Engineers.

e were two papers set down for reading, as follows :ription of the experimental apparatus and shaping machine > models at the Admiralty Experimental Works, Haslar," dmund Froude, of Haslar; "Description of the pumpings and water-softening machinery at the Southampton works," by William Matthews, waterworks engineer r the disposal of the usual formal business, the President illiam Anderson) referred to the International Engineerigress which was to be held in Chicago during the month ust next. He had received a letter from Mr. James , of London, who had been elected honorary president congress. Every one, Dr. Anderson said, knew of Mr. , so there was no occasion for him to say anything further head; but he trusted that English engineers would take cessary to a creditable representation.

next business was an alteration in the bye-laws, the chief to the class of membership. Hitherto the institution sisted of members, associates, and graduates. The two asses are, however, of small importance and practically tution is composed of full members. The qualification abership was that the candidate should be an engineer er twenty-four years of age; so that a member might be George Street magnate, or the head of a big engineer , down to a draughtsman or the foreman of a machine pposing of course he were an engineer and not simply inic or artisan. These conditions of equality do not however, to meet the views of the council of the instituthere are to be two classes of engineers on the register, and the little. These are to be known respectively as · and associate members, but as far as we can see the stinction is that the member has achieved success whilst ciate member has still his way to make. Honour to onour is due is a good maxim, but it may be doubted the practically self-elected council of an irresponsible

body should be the arbiters, not only of fame, but of professional status.

Resolutions embodying the proposed changes were moved from the chair, and carried unanimously. It need not be said that the new rule is not retrospective.

These matters having been settled, the secretary proceeded to read Mr. Froude's paper describing the apparatus in the Haslar establishment, over which he presides. To make clear the details of mechanism given would be quite impossible without the aid of drawings. These were supplied at the meeting in the shape of wall diagrams, but as members had not an opportunity of studying them beforehand, there were very few who were able to keep up with the reading of the paper, excepting those who already knew all about the matter. This is too often-we may say generally-the case in meetings of the technical societies; excepting always the Institution of Civil Engineers. Before this Society a paper is read on one evening, and, if its importance be sufficient, it is discussed during three sittings, each a week apart. Members have therefore an opportunity of grasping the details of the papers read, and preparing what they have to say beforehand. It is for this reason that the discussions before the Civil Engineers have always been instructive.

Mr. Froude's paper deals with but a fragment of its subject, but it takes the part which was more especially of interest to his audience, namely, the mechanical details involved in the apparatus used for testing the models by which a forecast is made of the performance of future naval vessels. It is well known that these forecasts are made possible by the late Mr. Froude's discovery of the law of "corresponding speeds," so that the speed, with a given power, of the full sized ship can be deduced from the performance of the model. The way in which the late Mr. Froude carried out his investigations, and how the original experimental works grew up at Torquay, under the wise encouragement of the Admiralty, are well known to all interested in physical science. It would be difficult to overestimate the good that has followed this work; for one thing it has done much to put us on an equality with our old rivals, the French-long, indeed, our masters in the science of ship design. Perhaps there is nothing upon which we could better found our claim to naval supremacy-in this long era of naval peace-than the possession of the only naval testing tank of its kind. It is a distinction we shall probably not long be able to boast, for the Russians, Italians, and Americans all contemplate constructing establishments of a like nature.

The paper commences with describing the principal features of the present Admiralty experiment establishment at Haslar. As at the former works at Torquay, the chief object consists of a long covered water-way, in which models of ships are towed to ascertain their resistance. The towing is done from a dynamometer carriage driven at definite speeds by a stationary engine working a wire rope. The models are made of hard paraffine, generally about 14 feet long, and something upwards of I inch in thickness as finished. They are cast in a mould with an allowance of about "for finishing the shape. The latter operation is done by hand, guidance grooves being cut in the model, so that the exact form may be preserved. The working of this shaping or copying machine, and the way in which it enables the lines of a drawing to be translated into model form, constitute one of the most interesting parts of the installation. The water-way, canal, or tank at Haslar is nearly 400 feet long, and of nearly uniform section throughout. The sides are of concrete and vertical, and the railway, on which the dynamometer carriage runs, is bedded on the tops of the side walls of the water-way, in place of being suspended over the water from the roof, as in the original design. The experimental carriage, which has to be nearly 21 feet gauge, is a trussed structure. Its principal peculiarity consists in the fact that the members of the several trusses composing it are wooden trunks or boxes about 4" square in cross sections, made of " deal, and put together with screws and shellac varnish. At the joints formed by the intersection of the various members of the trusses, the sides of the boxes are made to overlap one another over a large area, providing a large surface for screwing and for the adhesion of the shellac varnish. The dimensions of the boxes forming the several members of the girders are designed so as to bring the sides of the boxes into the right planes to suit these overlaps. The whole structure thus provided is remarkably rigid and light. The general design of the carriage is arranged so as to leave clear a sort of central alley provided with a railway, the rails of which are close to the sides

of the alley. The object of this secondary railway is to carry the smaller carriages, on which are mounted the actual experimental apparatus of different kinds; so that these may be adjusted on this railway to any desired position fore and aft on the main carriage. The carriage is driven by means of wire rope from a stationary 10" Tower spherical engine, a high power being required so as to start the truck quickly for high speed experiments. The ordinary speeds range between 100 and 500 feet per minute; for some classes of models experiments are occasionally made up to about 850 feet per minute or nine and a half miles per hour. The truck has been run at over 1200 feet per minute, or about fourteen miles per hour. The governor, by which the speed of the engine is regulated, is a very interesting and ingenious piece of mechanism, which has been modified from the design of that which was used on the engine at Torquay. There are two symmetrical bell-cranks carrying weights, and attached to each other by links, having slotted holes so as to allow the bell-cranks to have a very small range of freedom of angular motion. When a given speed of rotation is reached, the centrifugal force of the weights overcomes the tension of a spiral spring, provided for the purpose, and the governing action is brought into play in the following manner :-There is a hooked rod, by means of which the increase in the angular altitude of the weights (due to centrifugal force) brings a friction disc break into play, which in turn has the effect of extending a spiral spring connected with the engine throttle valve, which is thus closed so as to shut off steam. It will be easily seen how much more delicate an adjustment this device gives than the old Watt governor with the balls acting directly on the valve. The extension of the spring, and the consequent distance of departure of the throttle valve from its full open position are proportional to the frictional turning movement applied to the stationary wheel, which movement is itself proportional to the pressure brought to bear upon it by the bell-cranks; in other words it is proportional to the excess of the speed above that at which the centrifugal force of the weights just equals the tension of the spiral spring. To give greater sensitiveness of action the bell-cranks are not hung on pin joints but on flat springs after the fashion of a clock pendulum, safeguards being provided in case of the springs breaking. With the Torquay governor, which was similar in principle to that described, although differing in appearance, the adjustment was so delicate that a variation of speed in the running of the carriage of half a foot per minute was seldom exceeded even at the highest speeds. The value of working against the resistance of spiral springs will be noticed in this mechanism, their steadying action being especially valuable. It would be impossible for us to attempt to describe the mechanism constituting the copying apparatus of the model shaping machine, and we can only hope to give a mere outline of the general principles. A rough hollow model of the ship to be constructed is cast in paraffine wax, a material which is found to lend itself most perfectly to the necessities of the experiments. The drawing from which the operator has to work is stretched on a table, and the grooves representing the water lines are copied from the drawing by means of the mechanism. These grooves are formed by a pair of revolving cutters, the fore and aft motion being communicated to the model whilst the cutters move laterally. One cutter is on each side-for of course full models are required-and they approach or recede symmetrically in such accordance with the longitudinal travel of the model as to trace in plan upon it the intended horizontal section. This due accordance of the lateral motion of the cutters with the longitudinal motion of the model is accomplished by the operator so regulating the cutter motion as to maintain a tracer in contact with the corresponding water-line on the drawing. By suitable mechanism the drawing itself is made to imitate the longitudinal travel of the model, while the tracer imitates the lateral travel of the cutters. In the Torquay machine the tracer was guided by an adjustable template set to the curve of each water-line, but afterwards the tracer was made to follow the line on the drawing by the operator. In the present machine the cutters are raised or lowered to get the different water-lines. The cutters run at 2700 revolutions per minute. The grooves having been cut, the surplus material is removed by hand.

We shall not follow Mr. Froude in his description of the further details of the mechanism, as it would be unintelligible without the drawings by which he illustrated his description. The various arrangements are, however, fully worthy of study by all who are interested in ingenious mechanical devices; but

we must refer our readers to the printed transactions institution, in which the diagrams will appear when the is published. There is also a weighing machine, w necessary to obtain the actual dead weight of the model, the amount of ballast required to get the necessary displace corresponding to trial draught may be determined. Th will weigh up to 1000 lbs. with great accuracy, and is s principle to an ordinary chemical balance, except that steel yard, having one arm 6 inches and the other length.

The discussion on this paper was opened by Mr. White, the Director of Naval Construction, who is the head of the Admiralty department, of which the B establishment forms a branch. Mr. White spoke ~ advantage these model experiments had been to the saying that the great advance in the speed of ships # been obtained of late years would not have been reached full extent had it not been for the model experiments carr at Torquay and Haslar by the late Mr. Froude and h author of the paper. Mr. J. I. Thornycroft also port the great economy that had been made in expenditure navy ships by finding out beforehand what the proposed would do, and what was required in the way of power: that performance. Mr. Thornycroft made especial refere the ingenuity of the device whereby a line on the da which might not be quite accurate, would be made to desired result in the model, and this without an ex constructed apparatus. Various other speakers havin heard, and Mr. Froude having briefly replied, so far as 27 anything to reply to, the meeting adjourned unti evening.

On the members assembling on Friday evening inst., the president, Dr. Anderson, again occupied the Mr. Matthews's paper on the Southampton waterworks This contribution is interesting, as it describes what we stand is the largest water-softening plant yet installe quantity of water that can be satisfactorily deat from 2 to 2 million gallons per day of 24 hours course the principle of softening hard water by lime from new, but it has made slow progress, in spite o quantities of hard water, otherwise unobjectionable, the in the chalky southern half of our island. This limite tion of a means whereby a bad water in one respect a good one in all respects does not appear, to judge ceedings of last Friday, to spring from any inherent the system-beyond that which would arise from the the refuse lime in crowded cities-but rather from the ness of public authorities and water-supplying comp the wants and comforts of the people at large.

The meeting terminated with the usual votes of the President announcing that the summer meeting w this year at Middlesborough on Tuesday, August ! following days.

THE SEVEN IMAGES OF THE HUMAN IT is well known that in the human eye, besides he

image, which serves the purposes of vision, there three reflected images known under the name of images." M. Tcherning has discovered three add... so that the total number is brought up to seven.

In its passage into the interior of the eye each ray to pass through the cornea, the aqueous humour, the " lens, and the vitreous humour before finally arm, retina. At the surface of each of these constituents liable to be partially reflected, thus giving rise to images. These were all seen and described by fut beginning of the century, but only three were ob Helmholtz and others. These three can be easily two persons on holding a lighted match between the moving it about so that the reflections seem to pupil. One of them, that reflected by the front of is much brighter than the two others, which are k front surfaces of the crystalline and the vitreous he tively. The fourth image is due to reflection from surface of the cornea. It may be discovered by cares tion of the brightest image by means of a magnilya See Séances de la Société Française de Physize, An 1892.

pproaches the border of the pupil, and especially as it passes to the iris, it is seen to be accompanied by a small, pale, but -defined image, which always lies between the first image the centre of the pupil, the distance between them decreasas they move towards the centre, where they finally coincide. means of the ophthalmophakometer- an instrument consistof three incandescent lamps and a telescope arranged on an of 86 cm. radius-it was found possible to measure the radii Ervature of all the reflecting surfaces. The foci of the two ecting surfaces of the cornea were found to coincide, a fact ch accounts for the coincidence of the two corresponding ges at the centre of the pupil, and for Helmholtz's failure of ing the fainter one.

is evident that since the light reflected from the successive aces does not fall upon the retina, it is lost for visual pur5. But a comparison of the percentages of loss in the case e eye, and in that of a simple lens tells greatly in favour of former as an optical instrument. In the eye the percentage seful light is 97, in a simple lens 92, and in a compound cal instrument correspondingly less. But the light reflected ny of the internal surfaces is also liable to be reflected back the eye or the optical instrument, with the effect of superosing a more or less faint patch of light upon the image on etina. This is termed the noxious light (lumière nuisible) 1. Tcherning. In a simple lens this amounts to & per cent., st in the eye it is as low as o'002 per cent. But faint as it is capable of giving rise to two light impressions due to le reflection, one at least of which has been actually rved in the human eye. "The easiest way of observing it,' M. Tcherning, "is to look straight forwards in a dark room, ng a lighted candle in the hand about 20 cm. from the line On moving the candle gently from side to side a pale e of the flame is seen on the opposite side of the line of 1, distinct enough to show that it is inverted; it moves etrically to the candle with respect to the line of vision. ays which form this image have undergone, besides several tions, two reflections, one at the posterior surface of the alline and another at the front surface of the cornea." her image was expected to be formed by a similar reflecit the anterior surface of the crystalline. It was found in tificial eye, but not in the human sense-organ. However, sy calculation of the optical system of the eye explains this nstance. The focus of the reflected rays is very near the lline lens itself, so that they must be much dispersed by me they reach the retina. To enable the image to be d on the retina, the object would have to lie between the a and the crystalline, but on attempting to form a luminous at that place by optical means it is found that the "useful fill the eye to such an extent as to render everything else ole.

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found that different eyes differ in their capacity of seeing st of the two additional subjective images. Short-sighted = find it very indistinct unless the candle is held close to e, or convex glasses are used. As the maker of optical ments utilises the accessory images for testing the degree sh and the accurate centreing of the lenses, so the an is enabled to make valuable inferences from them as structure and condition of the eye he is examining, and ditional images discovered by M. Tcherning appear to considerable physiological importance. E. E. F. d'A.


E weeks ago we reprinted from the Botanical Gazette ndiana) a part of the first instalment of Prof. D. H. ell's interesting account of his vacation in the Hawaiian

The following is the chief portion of the second and ing instalment, published in the January number :e visiting the isle of Oahu, I made short trips to the of Hawaii and Kauai. The former, the largest of the and the only one where volcanic action is still going ached by steamer in about thirty-six hours from HonOn the way, the islands of Molokai, Lanai, and Maui ed. The first, a barren-looking and forbidding spot, scation of the leper settlement, to which all persons with leprosy are sent as soon as their condition becomes

Maui, the largest of the islands next to Hawaii, consists of two portions connected by a narrow isthmus. The whole eastern half is nothing more nor less than the body of an immense extinct volcano, ten thousand feet high, and with a crater nearly ten miles across. The other end of the island is an older formation. This island is said to be very interesting botanically; but, unfortunately, my time did not permit me to visit it.

Very soon after sighting Maui, the three great mountain masses of Hawaii began to loom up. The day was clear, and the whole formation of the island became visible. It consists of three great volcanic cones, of which only one is now active. The highest summit, Mauna Kea, is nearly 14,000 feet above the level of the sea; the next, Mauna Loa, lacks but a few hundred feet of this; yet so great is the breadth of these masses that one fails to realise their immense height. Our first landing was at Mahukona, on the leeward side of the island, a most forlorn expanse of bare lava with scarcely a trace of vegetation, except a few unhappy-looking algaroba trees planted about the straggling buildings that constituted the hamlet.

We lay all day at this inhospitable station, not getting away until evening. A beautiful sunset and a fine glimpse of the peak of Mauna Kea glowing with the last rays of the sun, form my most pleasant recollections of this desolate place.

What a change the next morning! On awakening we found ourselves entering the harbour of Hilo. Here everything is as green as can be imagined, and luxuriant vegetation comes down to the very ocean's edge. The town is built on a bay fringed with cocoa-nut trees and embowered in a wealth of tropical vegetation. Owing to the great annual rainfall (about 180 inches), as well as to the fact that Hawaii is the most southerly of the islands, the vegetation here is the most luxuriant and tropical found in the whole group. I remained in Hilo for six days and collected some most interesting specimens. Through the kindness of Mr. Hitchcock of Hilo, I was enabled to spend the night at his camp in the woods near the town, and the greater part of two days collecting in the vicinity. The forest here is most interesting. Mr. Hitchcock was starting a coffee plantation and has cut trails through the woods in several directions, so that collecting was very convenient. There is great danger of losing one's self in these woods where there are no trails, as much of the forest is an almost impassable jungle. In these moist forests ferns and mosses luxuriate, and every trunk and log is closely draped with those beautiful growths. Flowers are almost entirely wanting, a fact repeatedly observed by collectors in tropical forests. I saw here fully developed specimens of tree-ferns. The finest of these were species of Cibotium. Many had trunks from fifteen to twenty feet high, and some must have been fully thirty. The most beautiful were some with trunks ten to fifteen feet high, as these were more symmetrical and had finer fronds than the taller ones. I measured the leaves of one that had fallen over, and roughly esti mated the length as eighteen feet. I have no doubt that specimens fully twenty feet long could be found. These giant fronds, arching high over one's head as one rides on horseback under them, present a sight at once unique and beautiful. Growing upon the trunks of these ferns were many epiphytic species, the most peculiar of which was Ophioglossum pendulum, with long strap-shaped leaves, a foot or two long, and a spike of sporangia sometimes six inches long. Exquisite species of Hymenophyllum and Trichomanes, the most ethereal of all the fern tribes, with almost transparent, filmy leaves, were common, sometimes completely enveloping the trunks of the trees. Of the terrestrial ferns, which abounded everywhere, two were especially notable as; representing groups unknown in the United States. One of these, Gleichenia dichotoma, forms extensive thickets on the borders of the forest, and in the Hilo district extends down almost to the sea-level. The other, Marattia Douglasii, a very large fern with leaves eight to ten feet long in well-grown specimens, has fleshy dark green leaves, and thick stipules sheathing the base of the leaf-stalks. Several species of Lycopodium and Selaginella were common, and a good variety of mosses and liverworts. In these forests wild bananas are common, and most magnificent plants they are. Sheltered from the wind, the superb great leaves develop to their full size, without being torn in the least, and the whole plant is a study of beautiful form and colour.

Coffee is being extensively planted in this region as well as upon the lee side of the island, and as the quality of the berry

is exceptionally fine, this promises soon to be a leading industry in the islands.

About Hilo especially, but common also elsewhere, was a very conspicuous black fungus, that covered the leaves completely in many cases, and attacked indiscriminately a great variety of trees.


From Hilo I proceeded to the volcano of Kilauea, some thirty miles distant, and about 4000 feet above the level of the sea. As this volcano has so often been the theme of travellers' descriptions I will not linger over it. In the vicinity are many interesting plants, among them a species of Vaccinium with sub acid yellow and red berries something like cranberries. These "chele" berries are much esteemed, and are especially good when cooked. Some two miles from the volcano is a superb grove of koa trees, the largest trees I saw anywhere in the islands. One of these standing alone, and with magnificent spread of branches, must have been ten feet in diameter. The road to the volcano lies for much of the way through a fine forest. In the lower part the ohia trees were loaded with their beautiful crimson fruit, and present a very showy appearance. Of flowers, the species of Ipomea were the most conspicuous; but the scarlet flower-bracts of Freycinetia were conspicuous at times, for here this latter plant may often be seen running to the tops of the tallest trees.

The glory of this road, however, is the tree-ferns, which all along excite one's admiration. The carriage road is not yet completed, and about thirteen miles must be done on horseback. Of this more than a mile is over a corduroy road made out of the trunks of ferns! Such a road, if not very durable, is yet very pleasant to horses. As these trunks lay prostrate, in the damp atmosphere, most of them were already sending out new fronds, and in due course of time the road will be fringed with a hedge of great fern-leaves. Indeed, in some of the more open parts of the road farther down, where the ground is completely occupied by a small treefern growing in dense thickets, as these are grubbed out to make way for cultivation, their trunks are piled up to form fences, and soon sprout out so that they make a beautiful and close hedge of fern-leaves.

On leaving the volcano I went down on the other side of the island. The rain being almost entirely intercepted by the mountains, this leeward side is very dry, and the ride to Punaluu, where we were to take the steamer, was not especially pleasant. Vegetation is very scanty, and nothing particularly interesting was noted in this line. The soil on this side of the island, especially in the district of Kona, is very fertile, and when water can be had, produces magnificent crops of all the tropical staples, pine apples, cocoa nuts, coffee, sugar, &c., all especially hne; and we feasted on these cocoa-nuts and pine-apples as we sailed along this picturesque, if somewhat barren, coast.

A short, flying trip was made to the Island of Kauai, the richest botanically of all the islands, as it is the oldest geologi cally. According to Hillebrand, not only is the number of species larger than in the other islands, but the species are more specialised. Here I saw several species of the curious woody Lobeliaceæ, of which there are several genera that form either

shrubs or small trees. I saw several species of Cyanea, with stems six to eight feet high, with long leaves crowded at the top of the stem and many white or purplish flowers, much like those of Lobelia, but somewhat larger and less open.

As in all the islands, there is on Kauai a great difference between the windward and leeward sides. I drove for about thirty miles along the windward side of this island through some of the most beautiful scenery of all the islands. Near the sea were rolling plains and bills, with here and there groves of Pandanus and Hau-the latter a dense spreading small tree with large yellow hibiscus-flowers-and at one point we drove through a magnificent grove of kukui trees, the finest I saw anywhere. As we reached that part of the island which is most fully exposed to the moisture-laden trade-winds, vegetation became extremely luxuriant. Numerous valleys with clear streams flowing down them, their bottoms given up to rice plantations, were to be seen here, with the rice in all stages, from the young spears just standing above the water to golden-yellow patches of ripe grain. At Hanalei, my destination, I found excellent accommodation and a delightful bathing beach, the latter especially attractive after a thirty-five mile urive over dusty roads. Hanalei is beautifully situated on a picturesque bay, with bold mountains rising directly back. The next morning a native was hired to go with me into the woods, and the day was spent in collecting.

The variety of trees, as well as other phænogam. greater here than in Hawaii; the ferns, also, w**** Here I obtained a prize in a fine lot of the prothalla plants of Marattia, as well as some other interewing. Want of space forbids going into details, but a visiting the islands can afford to miss Kauai

In position, the Hawaiian Islands are unique, isolated than any other land of equal area upon the give than 2000 miles separates them from the mainla miles from the nearest high islands. Of purely voic thrown up from an immense depth, they have always ↑ isolated. As might be expected, the flora is very pecu so than in any other country. According to Hilleran species of spermaphytes and pteridophytes that ar indigenous, 653, or 75 per cent., are endemic Take pteridophytes, the spermaphytes show over 81 per the dicotyledons over 85 per cent. that are found group.

For a thorough study of this very curious flora ! would be necessary, as many species are extraordin and many of the most interesting localities are very access. The islands differ extremely among them exhibit in a most interesting manner the correspo exists between the variety and differentiation of terms ages of the islands. The formation of the islands has from north to south; and Kauai, the northernmost of 10 islands of the group, is also the oldest and much botanically, especially as regards spermaphytes; and a to Hillebrand, the genera and species are more difere Hawaii, the southernmost of the islands, is much the p forms, although in the Hilo district the conditions a favourable for a luxuriant development of forms.

In the latter island is the last active volcano of the Mauna Loa, with its two craters, of which the we crater of Kilauea is the great sight of the islands, a constantly by tourists from all parts of the world.

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A few days after my return to Honolulu from Kan ̧ a weeks from my first arrival there, I boarded the N through Australian steamer bound for San Francis was reached in due season after an uneventful passage ended my first trip to the tropics.


which is shown on the wall, is in all probabaty be Chōko, dating from the year A. D. 132. The new 2 used for keeping systematic records in Japan was !-Mallet. Since this not only have all forms of ses y modification of the contrivance sketched out by the la seismoscopes employed in Europe and America been en but many special forms have been designed in Japan, w result that rather than Japan borrowing from America, these countries are using inventions which ad origin in Japan. A few of these instruments are exti this laboratory. The main feature in their construction they all work from "steady points," and for smal earing at least, we can say with confidence that the diagrams ther are absolute measurements of the earth's motion. From written on stationary plates we know the extent and the of the principal vibrations in a shock, but when the m are recorded on a moving surface, we know the pers rapidity with which the movements follow each other these latter diagrams the acceleration or sullenness ments may be calculated, and the factors given in enabling them to construct to resist known for than simply building strongly because an earthquakes!

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The revolving plate is kept in motion by clockwork, which is et in motion by an electric seismoscope. (See No. 8.)

2. Seismograph writing on a drum.-In this instrument the ecord is written on a band of paper, the diagram being less ifficult to interpret because it is written to the right and left of straight line and not round a circle.

3. Seismograph writing on a band of paper.-In this instrusent not only is the diagram written along a straight line but is written with pencil,-the trouble of handling smoked paper eing therefore avoided. When the earthquake ceases, the drum eases to revolve, but if a second or third earthquake should ccur, it is again set in motion. By this means a series of arthquakes may be recorded, the resetting of the instrument eing automatic.

4. Seismograph without multiplying levers.-This instrument intended to record large motions, the horizontal levers not ing prolonged beyond the steady points to multiply the motion. or large earthquakes, when the ground is thrown into wavete undulations, special instruments which measure tilting are ployed.

5. Duplex pendulum seismograph.-In this case a steady int is obtained by controlling the motion of an ordinary ndulum with an inverted pendulum. The record consists of series of superimposed curves written on a smoked glass plate. 6. Mantelpiece seismometer.-This is intended for the use of ose who simply wish to know the direction and extent of ition as recorded at their own house. It is a form of duplex adulum, and it gives absolute measurements for small dis


1. Tromometer.-This is one form of an instrument which is d to record movements which are common to all countries, led earth tremors. Every five minutes, by clockwork contacts I an induction coil, sparks are discharged from the end of the g pointer to perforate the bands of paper which are slowly ving across the brass table. If the pointer is at rest, then a es of holes are made following each other in a straight line, if it is moving, the bands of paper are perforated in all ctions round what would be the normal line of perforations. The earth movements which cause these disturbances are arently long surface undulations of the earth's crust, in form unlike the swell upon the ocean.

more satisfactory method of recording these motions, which been used for the last two years, is by a continuous photooh of a ray of light reflected from a small mirror attached to nall but extremely light horizontal pendulum.

Electrical contact maker.-These instruments are delicate moscopes, which on the slightest disturbance close an tric circuit, which, actuating electric magnets, set free the hinery driving the recording surfaces on which diagrams


Clock. At the time of an earthquake the dial of this clock es quickly back and forth and receives on its surface three from the inkpads on its fingers. It thus records hours, ates, and seconds, without being stopped.

. Model of an earthquake.-The bent wires represent the traced by an earth particle at the time of the earthquake of ary 15, 1887. The numbers indicate successive seconds. model was made by Prof. S. Sekiya.

· Safety lamps.-These are lamps which if overturned are ce extinguished. One of these is a European invention he other Japanese.

Pictures. The pictures on the walls show the effects of Great Earthquake of October 28, 1891, the devastation wing the Eruption of Bandaisan in 1887, and several of the important volcanoes in Japan. They were made by Prof. K. Burton. JOHN MILNE, F. OMORI. smological Laboratory, Imperial University of Japan, Tokio.


FORD.-Last Term the Board of Faculty of Natural e recommended that an honour examination in Natural ze should be instituted, bearing the same relation to the School that Moderations bear to the Final School of Humaniores. The recommendation of the Board was nanimous, and on the matter coming before the HebdoCouncil last week, it was put aside on the ground of want

of unanimity among the various scientific departments. There was much to be said both for and against the proposed examination. It would probably have raised the standard of the chemical and physical work done by biologists, but would have forced an additional subject on the chemists and physicists, which they were very unwilling to assent to.

CAMBRIDGE.The Adams Prize has been awarded to Prof. J. H. Poynting, F. R. S., late Fellow of Trinity College, for a memoir on the methods of determining the absolute and relative value of gravitation and the mean density of the earth. The Professor of Pathology (Mr. Roy) gives notice that on Thursday, February 9, a lecture and demonstration will be given by Dr. Hafkine, of the Pasteur Institute, on his method of conferring immunity against Asiatic cholera. The lecture will be delivered at the Pathological Laboratory at 4.30, and will be open to members of the University.

The office of Esquire Bedell has been rendered vacant by the death of Mr. F. C. Wace, a distinguished mathematician, formerly Fellow and Lecturer in Mathematics at St. John's College, and thrice elected Mayor of the Borough of Cambridge.



Wiedemann's Annalen der Physik und Chemie, No. 1.— Essay towards an extension of Maxwell's Theory, by Hermann Ebert. The author obtains expressions for dispersion and absorption of waves of the order of light-waves analogous to those obtained by Goldhammer, and shows that they may be derived from Maxwell's fundamental conceptions by applying them to the case of rapidly changing displacements.-A new kind of magnetic and electric measuring apparatus, by G. Quincke. These are made of glass, ebonite, and wood. screws are used in their construction, and they are claimed to cost a tenth of the price of ordinary instruments, with equal accuracy. In each of them the needles are suspended at the hollow centre of a vertical circular glass disc.-On a null method for measuring the dielectric constants of conducting liquids, by Friedrich Heerwagen.-On a phenomenon analogous to Newton's rings observed during the assage of Hertz electric plane waves through plane-parallel metal plates, by Ludwig Boltzmann. The author removes an apparent contradiction between Maxwell's theory and Hertz's observation that even excessively thin metal plates do not transmit electric waves a few decimetres long, by showing that this is not due to absorption, but to the limiting conditions at the surfaces of separation deducible from Maxwell's formulæ. -On a medium whose mechanical properties lead to the equations propounded by Maxwell for electromagnetism, by L. Boltzmann.-On some questions concerning Maxwell's theory of electricity, by L. Boltzmann.-The index of refraction of electric rays in alcohol, by H. O. G. Ellinger.-On the electrification of air in glow and brush discharges, by Ad. Heydweiler.-On the calculation of magneto optic phenomena, by P. Drude.-Spectra of aluminium, indium, and thallium, by H. Kayser and C. Runge. -On the infra-red spectra of the alkalies, by H. Kayser and C. Runge. A criticism of Benjamin Snow's work on the same subject. Investigations concerning interior conduction of heat, by Richard Wachsmuth.-On the absolute value of the thermal conductivity of air, by A. Winkelmann.-On a modification of the transpiration method suitable for the investigation of very viscous liquids, by C. Brodmann. The substance was made to pass from a funnel-shaped reservoir through a capillary tube into a beaker standing on one pan of a chemical balance. The time was noted at which the amount of liquid passed into the beaker was large enough to overcome the counterpoise in the other pan, and to disturb the equilibrium, and further small weights were added and similarly dealt with. The temperature was kept constant by a spiral water-pipe and felt jacket, and local differences and variations of level and buoyancy were corrected for. The liquid experimented upon was glycerine, and the temperature curves were hyperbolas.-Notes on M. Cantor's thesis on capillary constants, by Th. Lohnstein.-Note on the purification of mercury, by W. Jaeger.

Notes from the Leyden Museum.-Of volume xiv. numbers 1 and 2 were published in April, and numbers 3 and 4 in July last. Edited by Dr. F. A. Jentink, this volume contains 282 pages and ten plates. The notes on Mammals are; by the editor on Semnopithecus pyrrhus, Horsfield; and on Pithecir melanurus, S. Muller (Pls. 3 and 4). In volume xii. Dr. Jentink,

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