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Thornycroft, with his turbine propeller, is able to em At Holyoke, Mass., the Water-Power Company, under phasize this economy of weight still further, and, but for Mr. James B. Francis, controlling the falls of the difficulties of going astern not yet surmounted, would be Connecticut, undertake the commercial testing of able to save considerable weight and space in sea-going turbines submitted to them, and have checked to some steamers with this contrivance.

extent the wild claims of efficiency, reaching and even As regards their construction, turbines are divided into exceeding 100 per cent., which American turbine makers three classes (p. 24)—the radial, axial, and mixed-flow are said to have claimed in their advertisements. There according to the mode in which the water enters and is still, however, an efficiency claimed for American passes through the turbine ; but as regards the dynamical turbines which has not been rivalled in Europe. this principle on which the turbines work, they are divided cannot be attributed to defect in our designs, and the into two classes (p. 25), the reaction and the impulse author thinks must be attributed to the less care bestowe i turbine.

in America on the measurement of the quantity of water In the reaction or Jonval turbine, described in chap- consumed. It is noticeable that the American turbines ters iii. to vi., the passages are completely filled with

are generally of the reaction Jonval type, which is more water, and the changes of pressure play an important suitable for their unlimited supplies of water by reason of part in the work performed. This turbine possesses the its smaller weight and cost; here in Europe, where water advantage of being able to work when drowned by the

is scarcer, the impulse Girard turbine is more in favour tail race, or when elevated above the tail water to a height For mining purposes, especially in California, with anything less than the height of the water barometer, a great falls of 400 or 500 feet and small quantities of Suction tube of properly adjusted shape being fitted below water, the hurdy-gurdy or Pelton wheel (p. 4191 is a the turbine to carry off the water at pressure gradually favourite, and in a paper by Mr. Hamilton Smith, Jan., increasing downwards to the atmospheric pressure. of the American Society of Civil Engineers, the effi zreacy Against this are the disadvantages of imperfect regula- of this wheel and its practical advantages are declared to tion for varying load, and that with a high fall this turbine be very high. Similar small impulse turbines seem likaly must be made so small and must run so fast as rapidly to to come into general domestic use. wear out, as in the Fourneyron turbines at St. Blaise The author concludes (chapter xiii.) with a description (p. 422); but this disadvantage the author professes (p. of the various hydraulic pressure engines and moton of 263) to avoid by compounding the turbine, just as we Armstrong, Rigg, and others. These engines act by compound the steam-engine with high-pressure steam. pressure only, like the steam-engine, with the disadvant

The impulse or Girard turbine, on the other hand age of using the same quantity of water whether working (chapters vii. and viii.), derives its power entirely from at high or low power, except in the case of Mr. Rigg's the change of momentum of the water without change motor. Such motors are, however, coming into great of pressure; the buckets are freely ventilated, and use on ships, not only for working the guns, but for consequently this turbine can only work in communica- steering, loading, and discharging cargo. tion with the surrounding air. It possesses, too, the Although designed, and amply fulfilling its purpose, as great advantage of complete regulation of power by a practical treatise on hydraulic motors, this book will merely altering the supply of water. Girard turbines are provide the pure theorist with some of the most elegant divided into outward flow (Fourneyron) turbines, and applications of relative velocity, aberration, dynamical inward flow (James Thomson); the latter, although more principles, and of hydromechanics; and it is instructive weighty and costly, possessing the advantage of greater to notice that, as in all practical mech inical treatises, stability of motion.

gravitation units of force only are employed, even in the In their difference of action we may compare the hydrodynamical equations of Borda and Carnot, or of Jonval turbine with the screw propeller, which works Bernoulli

, as we think they should be called. All this entirely immersed, and derives its reaction partly from is in direct opposition to the theoretical text-books ; the change of pressure in the water ; while the Girard theorist or practical man, which is to give way? ! turbine resembles the paddle-wheel in working at the

A. G. G. surface of separation of the water and air, so that no appreciable change of pressure is manifest. Against this analogy, however, we find the screw propeller far less

PHYSIOLOGY OF EDUCATION. susceptible to changes of immersion than the paddlewheel, whence the manifest superiority of the screw for Physiological Notes on Primary Education and the long voyages.

Study of Language. By Mary Putnam Jacobi, M.D. In chapters ix. to xi. the author gives a very valuable (New York and London: G. P. Putnam's Sons, 1889.) collection of e numerical applications of his theories to This is a remarkable beobws The authoress is an to utilize a fall, the first important measurement is that of thoughts clearly and strongly. It is worthy of being read the quantity of the stream of water; the speed of the by all interested in the science of education, though few turbine is next determined from the consideration that perhaps even of the advocates of the present educational the best theoretical speed is half (or a little more than renaissance would be prepared to receive every one of half) the speed at which the turbine would run if un- her conclusions. loaded ; and then various practical considerations inter The work consists of four distinct essays. The first vene in deciding whether the turbine should be reaction two are entitled " An Experiment in Primary Education," or impulse, outward, inward, or mixed Aow.

and describe the way in which Dr. Mary Jacobi taught

her own little girl. She commences the account with but she would have several forms of Aryan speech some very valuable remarks on the right order of studies. studied simultaneously, and she would postpone the

“ The first intellectual faculties to be trained are per study of grammar till two years after the serious study ception and memory. The subjects of the child's first of language has commenced. She believes that the studies should therefore be selected, not on account of power of abstraction and the general mental training their ultimate utility, but on account of their influence gained by these philological studies will enable the young upon the development of these faculties. What sense is person at an early age to enter upon more serious matters there then in beginning education with instruction in the of study or those of more immediate practical utility. arts of reading and writing? ... From the modern stand

J. H. G. point, that education means such an unfolding of the faculties as shall put the mind into the widest and most effective relation with the entire world of things-spiritual

OUR BOOK SHELF. and material, there is an exquisite absurdity in the time: Steam-Engine Design. By Jay M. Whitham, Professor of honoured method. To study words before things tends to impress the mind with a fatal belief in their superior

Engineering, Arkansas Industrial University. (London:

Macmillan and Co., 1889.) importance."

In this work the author treats of the application of the As forms and colours are the elements of all visual principles of mechanics to the design of the parts of a impressions, Dr. Jacobi began to teach her child geome- steam-engine of any type or for any duty. He acknowtrical forms before she was four years of age. At four ledges that he has culled as much information as he has and a half the little girl began elementary colours. After required from well-known sources, both English and wards she made acquaintance with the points of the for his work, a course of lectures given to his class at the

American ; and he has embodied, as a sort of foundation compass, the main ideas of perspective, and then maps United States Naval Academy by P.A. Engineer John C. and geography, The study of number, of course by Kafer, U.S.N. concrete illustrations, followed that of form and outline. After careful study, we can say that the book appears The observation of natural objects, especially that of to be well suited for its purpose. The arrangement of plants and plant-life, was then commenced. The growth of same as that in Mr. A. E. Seaton's excellent work on beans and hyacinths was carefully watched, and the daily marine engineering ; but the field covered is of far less observations made by the child were written down by extent, and the boiler and its accessories are not included. the mother, till she attempted them herself, and became The author being a Professor of Engineering in an gradually initiated into the mysteries of writing. This American University, we expected to find some variations led her on easily to the art of reading when she was about from our own practice in steam-engine design. In this, six years of age. The progress of the child's mental however, we were disappointed. A few of the woodcuts development during these early years is fully described, from those used in this country, but the main design is

represent parts of engines differing in insignificent details with many pleasant recollections of her sayings.

practically the same. It is gratifying to find many of our The third part consists merely of a criticism of Miss own engineers quoted as authorities in the volume—viz. Youman's views on the teaching of botany, and an D. K. Clark, A. E. Seaton, R. Sennett, and many other argument in favour of commencing in a child's education well-known English authorities. with the flower rather than the leaf.

It must not be supposed that there is no original work Half the book, however, is occupied by the fourth essay, design of slide valves and reversing gears, are ample

in this book. Chapters ii. and iii. for instance, on the in which the authoress treats of “ The Place for the Study evidence of hard work on the part of the author : his of Language in a Curriculum of Education.” Of course she descriptions and diagrams of the various motions are places it after the mind has been trained to deal with sense excellent. Chapter iv. deals with the general design and perceptions of external objects ; but she contends earnestly connections. Chapters v. and vi. are on compound and

proportions of the steam-chest, valves with their various for the importance of the study of words, especially for triple-expansion engines, and contain also a theoretical the power it possesses of enabling the child to form treatment of indicator diagrams of a compound engine. abstract conceptions. The authoress enters largely into These chapters are well written, and contain much useful the brain action involved in the use of verbal signs or information, but as a whole they do not teach anything complex ideas, and illustrates her views of the matter by new. To chapters vii. and viii., written by P.A. Enmeans of physiological diagrams. She also describes a apply. The remaining chapters deal with the design of

gineer Asa M. Mattice, U.S.N., the same remarks will little device for the comparison of verbal roots, which she the various other parts of a steam-engine. The methods terms " language tetrahedrons," and which are intended used are those well understood in every drawing office to show the relation between Latin, French, German, and worthy of the name, and they need not be further noticed English. She would devote to literary studies, including here. English, the best part of the time between the Kinder

Taken as a whole, the book deserves praise for good

and careful work; and we may especially call attention to garten training and the age of fourteen.

the theoretical considerations, which are always clearly "To the study of words may be brought the scientific expressed. Although published by Messrs. Macmillan, methods used in the study of things-observation, analysis, the work is from an American press, that of Messrs. comparison, classification; and the child may thus begin Ferris Bros., New York. The printing and woodcuts are to be trained for physical science at a time when excellent, far better, as usual, than English work of the the pursuit of most physical sciences is impossible.” same class.

N. J. L. It may be that Dr. Mary Jacobi claims too much time Coloured Analytical Tables. By H. W. Hake, Ph.D., for the study of language, but the old-fashioned education F.I.C., F.C.S. (London: George Phillip and Son, 1889.) alists will get little consolation from her concessions ; for NOVELTIES in text-books of elementary qualitative anashe not only places the study of words after that of things, I lysis are usually conspicuous by their absence, but the

book before us takes an entirely new departure. The knowledge ; and hence the fact that the book contains two idea of representing the various coloured reactions by of his lectures delivered at the London Institution las tinted imitations is, so far as we know, quite new. Apart November is in itself sufficient commendation. However, from this, the usual well-worn paths are followed. The be this as it may, we have no hesitation in saying there tables are of the simplest character, and are only sufficient could hardly be a clearer explanation of Prof. George for the detection of common bases in salts or oxides, Darwin's theory of tidal evolution than that contained is no attempt being made to separate the members of the the work before us. The hypothesis being accepted, every various groups. The second part is devoted to reactions feature of the past and future condition of our satellite for

the detection of a few acids and organic substances, is described in a most comprehensive manner. It is first The book is apparently primarily intended for the use shown how, when the earth was rotating on its axis with of students preparing for the preliminary examination of an enormous velocity, the tidal action set up by the the Conjoint Board of the Royal College of Physicians sun caused a portion to become detached and form our and Surgeons, but it will no doubt have a much wider satellite. The employment of the term “conservation field of usefulness if it survives the test of experience. of spin ” facilitates considerably the demonstration of The new method of representation seems excellently the fact that as by tidal action the spin of the earth adapted for young students, and certainly no harm can decreases-as our day lengthens--so must the dimensions be done by giving it a fair trial.

of the moon's orbit be increased, and the length of the The reactions illustrated include precipitates, charcoal month therefore become proportionally greater. The art reactions, borax beads, and flame colorations, most of plication of Prof. Darwin's theory to other members of which are fairly well represented.

our system is also inquired into ; and although the author The Story of a Tinder Bor. By Charles M. Tidy, M.B.M.S., does not attempt to go back to the first stage in the

F.C.S., &c. (London : Society for Promoting Chris- evolution of celestial species, he shows that tidal evolution tian Knowledge, 1889.)

is an extension of the hypothesis that does so. Indeed, POPULAR lecturers have discovered for some time that the scientific reader will be found exceedingly interesting.

the book is replete with information, and by the general history of the methods that have been used for obtaining a light is an excellent subject wherewith to please the public mind, and this book contains the reports of three such lectures delivered to a juvenile auditory last

LETTERS TO THE EDITOR. Christmas. An attempt has also been made to describe the experimental portion of the lectures, and the author (The Editor does not hold himself responsible for opinions ehas not committed the common error of giving a mul

pressed by his correspondents. Neither can he underlak tiplicity of pretty but irrelevant experiments conveying

to return, or to correspond with the writers of, rejected

manuscripts intended for this or any other part of NATURI, a paucity of information. In fact, in some parts the reverse

No notice is taken of anonymous communications. ] seems the case, for we must confess our inability to discover why a consideration of the allotropic modifica

Specific Inductive Capacity. tions of carbon should necessitate a detailed description of the manufacture of black lead pencils. This digres

PERHAPs a better mode of performing the experiment quote! sion, however, does not detract from the interest and by Mr. Rudge (p. 10) is to have two insulated parallel metal general merit of the work, which certainly contains the plates, one connected with an electroscope, the other with a explanation in simple language of some elementary of paraffin or ebonite (recently passed through a fame) between

slightly-charged Leyden-jar. On now interposing a thick slab physical and chemical phenomena.

the plates, a very decided increase of divergence will be perMagnetism and Electricity. Part I. Magnetism. By

By ceived.

Unless, indeed, the electroscope should happen to Andrew Jamieson, M.I.C.E. (London: Griffin and have overflowed to earth during the charging of the jar, in which Co., 1889.)

case it will be oppositely charged and a decreased divergence ALTHOUGH elementary text-books of physics continue to diminish the distance between the plates, and its effect is there

may be caused. "To interpose the slab is, in fact, virtually to increase in number, there is still room for one of such fore the same as that of pushing the plates closer together. general excellence as Prof. Jamieson's elementary manual. The advantage of the Leyden-jar is that it keeps the potential The book is specially arranged for the use of first year practically constant. If an isolated plate or sphere is used as Science and Art Department and other electrical students. The charged body the circumstances are not so simple ; for the Numerous questions and specimen answers are distributed insertion of the slab reduces the potential and slightly increases throughout the book, and though this may be rather the charge on the near face of the plate, so that whether the suggestive of cram, there is nothing in the text to justify divergence of the leaves is increased or diminished depends on such a suggestion. It is unnecessary to go into details, several unimportant considerations, of which the size of the slab but it may be stated that the arrangement of subjects is may be one. A slab of area comparable to that of the plates as good as it well can be, and on the whole the descrip- and

in any case it should be supported by a long insulator, sa

between which it is put would in this ca e be the most suitable : tions are very clear. The numerous diagrams are also that the operator's arm, as it approaches, shall not complicate excellent, those of the mariner's compass being especially and mask the effect.

OLIVER J. LODGE. good ; indeed, the whole chapter on terrestrial magnetism

University College, Liverpool, November 9. is the best elementary account of the subject which has come under our notice. The subject is throughout considered as an essentially

"La Pietra Papale." practical one, and very clear instructions are given for the making of magnets, and compass and dipping needles.

ABOVE Stresa, on the western bank of Lago Maggiore, there is If the succeeding parts of the book confirm the good an enormous granite boulder, which deserves the attention of opinion created by the first, teachers of the subject are to geologists. It lies on the left slope of an old moraine, near the be congratulated on having such a thoroughly trustworthy an elevation of about 2500 feet above the sea-level. It is roughly

little village of Gignese, and not far from the Hotel Alpino, a! text-book at their disposal.

oblong in shape, and measures some 75 feet in length, and Time and Tide : A Romance of the Moon. By Sir Robert perhaps half as much in breadth and thickness. The projected S. Ball, LL.D., F.R.S. (London : Society for Promoting mountain railway from Stresa to the summit of Monte Motterone Christian Knowledge, 1889.)

will pass close to the spot where it lies, and the masons are The ability of the author of this work to give a lucid stones. Ti is to be hoped, however, that la pietra Aapale


already engaged in converting the smaller boulders into buildingexposition of an abstruse subject is a matter of common as this splendid example of the carrying powers of ice is

called by the villagers, will not suffer the like fate. The Italian direction or another, and the difficulty experienced in thoroughly Alpine Club, will, we may trust, interest themselves in this extirpating them. matter.

P. L. SCLATER. In connection with the species which forms the subject of the Hotel du Parc, Lugano, October 21.

present communication, I notice that Murray, in his work on the "Aptera,” says: “It occasionally occurs in such numbers

as almost to denude the trees of their foliage ; and it has been Who discovered the Teeth in Ornithorhynchus ? noted that the stems and branches of such trees seemed covered As Dr. Hart Merriam's letter on the above subject in your with a bright glaze. Can this be a fine web?" It was so, most issue of the 7th inst. (p. 11) will be read by many who have not certainly, in the present instance, which afforded me a most access to Sir Everard Home's "Lectures on Comparative favourable opportunity for examination. Again, it appears that Anatomy," allow me to point out that the description and figures the mites are normally found on the under-surface of the leaves, in that work referred to by Dr. Merriam have no bearing whatever' which they cover with a fine web of silk, on which (to again upon the very interesting discoveries recently made. They quote Murray) "they are sometimes crowded together in vast represent, not the real teeth of the young animal discovered by numbers ; for example, we have seen them so thick on the leaves Mr. Poulton, and fully described by Mr. Oldfield Thomas, but that they looked as if they were not merely sprinkled with a yellow the well-known horny plates which functionally take their place orange coloured powder, but as if it was actually in parts heaped in the adult, and which are called "grinding teeth” hy Sir up on them, so that none of the green colour of the leafwas visible.” Everard only in a very general sense. W. H. FLOWER.

Their presence is of course highly injurious, causing the leaves British Museum (Natural History), November 9.

to shrivel and drop; and it seems to me that the fact of their occurrence on the bare bark of the trunks was attributable to the

death of the leaves causing them to retreat to that position, The account of the teeth of Ornithorhynchus, given by Sir uncongenial though it would seem to be. Such trees as preEverard Home in "Lectures on Comparative Anatomy," vol. i. served their foliage presented no abnormal appearance on the P: 305, explanatory of Tab, lix. vol. ii., referred to by Mr. Hart branches, &c., notwithstanding which, in one

or two instances, Merriam in your last issue (p. 11), shows, even more clearly I believe the parasites were present on the leaves, though seemthan the figures, that the truc teeth had not been noticed at that

ingly not in such extraordinary profusion. time (1814). The passage is as follows :-"In the posterior

Dugès, writing of T. telarius, states his belief that that species portion of the mouth, both in the upper and lower jaw, are

passes the winter under stones, and instances the finding of placed grinding teeth with broad flattened crowns, four in num

several active individuals so situated in a garden near Paris in ber, one on each side of each jaw. They are composed of a horny the month of October. Regarding this point I may say that my substance (the italics are my own), only embedded in the gum,

specimens of 7. tiliarum, which I placed in a box immediately to which they are connected by an irregular surface in the place in the most convenient nooks and crannies, in which they


after removal from the trees, speedily ensconced themselves of fangs. When cut through, the substance appears fibrous, like that of nail; the direction of the fibres being perpendicular fine webs. It may be worth noting that the days on which my to the crown, similar to that of the horny crust of the gizzard. observations were made were warm and damp, with scarcely The teeth in the young animal are smaller, and two on each any wind, quite typical early autumn days in fact. side, so that the first teeth are probably shed, and the two small

F. R. Rowley. ones replaced by one large one."

Leicester Museum. It is perfectly evident that here no reference is made to the truc teeth, and, moreover, the figure of the two smaller "teeth"

Retarded Germination. of young specimens represents merely the immature horny plates. The honours, therefore, still remain with Mr. Poulton

I Shall be much obliged to any of your readers who can give and Mr. Oldfield Thomas.


an explanation of the probable cause of the above phenomenon, Anatomical Department, The Museum, Oxford,

which I have remarked this year. I sowed a number of patches

of seeds of various hardy annuals in the garden in the last week November 8.

of April ; about half of them came up after the usual interval,

strongly and regularly. Such were Calendula Pongei, ConOn a Mite of the Genus Tetranychus found infesting

volvulus minor, Lavatera trimestris, Collinsia bicolor, Iberis Lime-trees in the Leicester Museum Grounds.

white and red, Specularia speculum, Linum rubrum, &c., &c.

Then there were some of which a few scattered seedlings made ABOUT the 13th of last September my attention was called to their appearance at this time, and after an interval of about six the strange appearance of a row of lime-trees standing in front weeks the greater part of them also came up; among these were of the School of Art buildings in Hastings Street. On examina- Eutoca viscida, Nigelia damascena, Sphenogyne, and Clarkia tion I found that the whole row, with, I think, only one excep- pulchella. Thirdly, there were some of which I quite despaired ; tion, were almost entirely devoid of leaves, the trunks and mignonette, however, appeared thinly about the end of June, branches being covered with a fine web, very closely spun, and at intervals till August ; and in the middle of June a few giving them the appearance of being coated with a thin layer of plants (in proportion to the seed sown, a few) of Linaria bipartita, ice, this glazed look being specially noticeable when standing in Madia elegans, and Xeranthemum came up-one consequence such a position as to catch the reflected rays of the sun. At first being that the last named has not yet flowered. Some of the sight I imagined that I was examining the work of a spider, seeds were obtained this spring from seedsmen, some were my thongh I was unable to recollect any whose webs would accord own collection of the last year or two-of the latter were with the character of those under observation. However, a Calendula, Lavatera, Convolvulus, Specularia, Eutoca, Nigella, close inspection revealed the webs to be tenanted by an in- Sphenogyne, and mignonette--so that cannot be said to give any numerable number of yellowish or orange-coloured mites which clue. "The conditions for germination and growth were favourwere in some places associated together in dense masses or able, and the season also. I have never remarked before any clusters, and more or less abundant over the whole of the trunks annuals so long in appearing above ground ; though in some and branches.

herbaceous plants I have noticed it, 2.g. Gaillardia, Myosotis These mites appeared, on being subjected to a careful alpestris, and Anemone coronaria.

E. A. microscopical examination, to be identical with Tetranychus Herefordshire, September 19. tilianum, Mull., a species which it seems that Claparède conriders to be only a variety of T. Ielarius, the common “red spider." However that may be, they are at any rate closely allied forms-members of the family Trombidiida, which pos

The Relation of the Soil to Tropical Diseases. sess, as one of their distinguishing characteristics, a pedipalpus As a humble subscriber to and student of NATURE, will yon with a claw and a lobe-like appendage. In the genus bear with me while I ask your help, as shortly and plainly as I Tetranychus the palpi are chelate, the mouth is furnished with a can? I am in a very secluded corner of one of the Native States tarbed sucking apparatus for the extraction of plant juices, and of Rajpootana, and I am collecting facts and making observaspinning organs are usually present. It is needless to comment tions on the relation of the soil to tropical diseases ; my ambition upon their destructiveness to vegetation, for most keepers of being to discuss it not so much from a statistical and geographical gardens and hothouses are familiar with their ravages in one standpoint, as from the geological, in its chemical and biological

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aspects ; though, as I conceive, the geographical, climatological; ON THE HARDENING AND TEMPERING OF and geological elements in the problem are not to be arbitrarily distinguished. Now I am far away from all books of reference,

STEEL and it is of course essential that I make myself acquainted with what has already been done in these subjects, and I venture to

II. ask for any hints as to the bibliography of them. Can you tell me if anyone has done for geology what Hirsch, of Berlin, has done for THE following considerations appear to have guided any authority on the chemistry of soils, and what I roughly call p. 16) Bearing in mind the fact that molecular change in a their physiology and pathology, their structural and functional body is always accompanied by evolution or absorption of changes under influences-climate notably-and their own in- heat, which is, indeed, the surest indication of the occurtrinsic, and the deeper geological interactions ?

rence of molecular change, he studied with the aid of a

A, ERNEST ROBERTS. chronograph what takes place during the slow cooling Meywar Bheel Corps, Kherwara, Central India,

and the slow heating of masses of iron or steel, using, as September 9.

a thermometer to measure the temperature of the mass, a thermo-electric couple of platinum and of platinum con

taining 10 per cent. of rhodium, converting the indicaThe Earthquake of Tokio, April 18, 1889.

tions of the galvanometer into temperatures by Tait's DR. VON REBEUR-PASCHWITZ's letter, which appeared in formulæ. NATURE, vol. xl. p. 294, is of special interest to us in Japan, countenancing as it does the conjecture that the very peculiar earthquake felt and registered here on April 18 was the result of a disturbance of unusual magnitude. It was my good fortune on the day in question to be engaged in conversation with Prof. Sekiya in the Seismological Laboratory at the very instant the earthquake occurred. We at once rushed to the room where the self-recording instruments lay, and there, for the first time in our experience, had the delight of viewing the pointers mark

G their sinuous curves on the revolving plates and cylinders. At first sight it seemed as if the pointers had gone mad, tracing out sinuosities of amplitudes five or six times greater than the greatest that had ever before been recorded in Tokio. There was not much sensation of an earthquake ; indeed, after the first slight tremor that attracted our attention, we felt nothing

S at all, although in the irregular oscillations of the seismograph pointers we had evidence enough that an earthquake was passing. Very few in Tokio were aware that there had been an earthquake till they read the report of it in the next day's papers. Thus the motion, though large, was too slow to cause any of the usual sensations that accompany earthquakes, and suggested a distant origin and a large disturbance, with a consequent wide extension of seismic effect. Excepting the slight Tremors recorded at Potsdam and Wilhelmshaven, there has been, so far, no evidence of any such far-reaching action.

My object in writing this note, however, is to correct an error of calculation which Dr. von Rebeur-Paschwitz has unwittingly

R made. He has assumed that Tokio standard time is mean local time. On the contrary, the standard time for all Japan is the mean solar time for longitude 135° E., -that is, nine hours in advance of Greenwich mean time. Hence, instead of the Tokio

FIG. 6. earthquake having preceded the German disturbance by ih. 4*3m. it preceded it by only 45m. This correction increases the Figs. 5 and 6 show the actual mode of conducting the experiments. ¥ (Fig. s) is

a piece of steel into which a platinum and platinum-rhodium couple, , !. velocity of transmission to 3060 metres per second. We must is fixed. It is inclosed in a glazed porcelain tube and heated to bright assume, then, either that large disturbances in the heart of the redness in the furnace, s (Fig. 6). This tube, T, may be filled with any earth travel with exceptionally high speeds, or that the origin of

gaseous atmosphere. 'c is a bulb filled with chloride of calcium. The the disturbance was a considerable distance from Tokio. The

metal under examination is slowly cooled down. The wires from the

thermo-couple pass to the galvanometer, G. The rate of cooling of the latter assumption seems sufficiently satisfactory, if in other mass is indicated by the movement of a spot of light from the galvano respects Dr. von Rebeur-Pasc.iwitz's views meet with approval. meter mirror at m, on the screen, R, and is recorded by a chronograph


The source of light is shown at L; M is a reflector. Imperial University, Tokio, Japan, September 25.

In the next diagram (Fig. 7) temperatures through which

a slowly-cooling mass of iron or steel passes, are arranged A Brilliant Meteor.

along the horizontal line, and the intervals of time during YESTERDAY evening, November 4, at 7.55 p.m., I was for which the mass falls through a definite number (66) of tunate enough to observe a very brilliant meteor. ' It became degrees of temperature are shown vertically by ordinates. visible almost exactly at the zenith, or a little west of it, and See what happens while a mass of electro-deposited iron moved, as nearly as I could judge, due east, magnetic ; it re- (shown by a dotted line),

which is as pure as any iron can mained visible for about from one to two seconds, disappearing, be, slowly cools down. From 2000 to 870° it falls unifinally, rather low down on the eastern horizon. For the first formly at the rate of about 2-2° a second, and the intervals half of its journey it was of a dazzling white brightness, and then of temperature are plotted as dots at the middle of the it suddenly became a dull red spark. The light emitted from it successive points of the intervals. When the temperature when brightest reminded me of the light from an arc lamp, and falls down to 858°, there is a sudden arrest in the fall of was very much brighter than any of the fixed stars. As it was so short a time in view, and there were no stars

temperature, the indicating spot of light, instead of falling visible, I could only approximately estimate its point of appear

at a uniform rate of about 2° a second, suddenly takes 26 ance and path. There were a few clouds about, mostly in the west, and the moon was behind them. PAUL A. COBBOLD.

" A Lecture delivered on September 13, by Prof. W. C. Roberts-Austen,

F.R.S., before the members of the British Association. Continued from Warwick School, November 5.

P. 26

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