Feb. 9, 1870.]

THE STATUES OF EASTER ISLAND.' HE account of Easter Island and its statues, as lately told in our pages by Mr. Martin Tupper, in consequence of the arrival in this country of some of the figures, has scarcely excited so much attention out of doors as it properly calls for. The facts are so remarkable, and the mystery surrounding them so great, that we are prompted to place before our readers all the materials available for forming a judgment on the points in question. By the kindness of Lieut. Harrison, we are enabled to give a sketch plan of the island, a view of part of it, with its marvellous grove of gigantic heads, and a representation of one of the recumbent figures, with the singular tufa crown, to which reference has before been made. To these we add representations, back and front, of the two figures brought from the island, and now in the British Museum.

Contemplate the broad fact for an instant. Here on this barren island, not thirty miles round, in the midst of the vast Pacific Ocean-an island, treeless, metalless, and foodless, occupied by a few wretched savages, and 2,500 miles from its nearest continental neighbour,-more than 300 of these stone statues, 20 ft., 30 ft., and in one case at least 50 ft. high, some of them standing on long platforms of Cyclopean masonry, have been counted, and how many more there may be in the interior is not know n to us. When and by whom were they made? The people now inhabiting the island know nothing of their origin or purpose, and take no interest in them: they have no tradition

For the use of the block of this illustration we are indebted to the Editor of the Builder.

A submergence of vast tracts of land similar to that suggested with reference to Easter Island probably took place in the Atlantic. Scholars will remember the tradition in Plato's dialogue, entitled Timæus, making direct mention of a great Island of Atlantis, situated beyond the pillars of Hercules. On this extensive Atlantic island there was a powerful kingdom. In an evil day, he writes, this island sank into the ocean. Professor Unger, of Vienna, in a valuable lecture on this sunken island of Atlantis, of which a translation is published in the Journal of Botany, gives very interesting evidence in favour of this tradition from the flora and fauna, and in support of the theory that, "in the Tertiary period, or when lignite was formed, Europe must have been connected with North America, and the Atlantic ocean must have been divided at one place or another by a continent." The continental connection of Australia and Europe during the Eocene period is argued for. No metal nor even flint is found on Easter Island, but only some hard stones, capable of being fashioned into so-called celts. Were these figures produced with such instruments ?

The workmanship is rude, but not bad. Some description of those in the British Museum, and now illustrated by us, we have already given, and need not repeat it. Observe the excellent conventional treatment of the arm and hand, and of the jaw and chest in the larger figure. The ears (if they are ears) are very peculiar. The carving on the back of the smaller figure, tufa, is very remarkable; the band in the larger figure is clasped in the two hands. The receding forehead and projecting mouth are very striking. The tufa crowns are also singular, and are in many cases 6 ft. high, and 5 ft. in diameter. These must have been placed on the top of the statues after their erection,--not an easy task. . . .

It does not seem certain that we may claim for these figures a very high antiquity: they are very Mexican in appearance, and their age may be not greater than that of the ruined cities of Central America, of which we know. The submergence might have taken place in the Middle Ages, without any intimation of the momentous occurrence reaching us. They may, however, be very much older. Anyhow they represent a most extraordinary phenomenon, and present very curious questions for consideration. We can recall nothing more remarkable than the view we now give of part of the island, with its growth of statues.-Builder.

REVIEWS OF BOOKS.

Qualitative Chemical Analysis. By DR. C. REMIGIUS FRESENIUS. Seventh Edition. Edited by ARTHUR VACHER.

London: John Churchill & Sons. 1870. Quantitative Chemical Analysis. By DR. C. REMIGIUS FRESENIUS. Fifth Edition. Edited by ARTHUR VACHER. London: John Churchill & Sons. 1870.

WE

E doubt very much that an English chemist will be found in the present state of things who can write a work on chemical analysis equalling, both in exactness and minuteness of detail and in the originality of its contents, that which can be written by a German. At least in Germany we find chemists who are both able and willing to devote a lifetime to the developing and perfecting processes for the detection and quantitative estimation of substances, and are not very likely to find such men in England. We are led to express this opinion by having before us the new English editions of the two volumes of Fresenius on Chemical Analysis. The Wiesbaden professor is a pre-eminent instance of one who has devoted a lifetime to the object we have indicated. He has raised in these works monuments to the vast assistance he has afforded to other chemists in their labours, which will remain long after him, but which can never bring him that renown that an equal application of his abilities and time to other branches of his science would have done.

The treatises on Qualitative and Quantitative Analysis by Fresenius have for a great number of years been familiar to English students and teachers of chemistry in the excellent translations of Mr. Lloyd Bullock. They are now given to us by the hands of Mr. Arthur Vacher, who has not merely reproduced the substance of them, but has freely availed himself of his editorial capacity to make such modifications as he deemed improvements in them.

We cannot epitomize more briefly than the editor has done the differences between the sixth edition of the Qualitative Analysis and the seventh :

"Several improvements, necessitated by the progress of discovery, have been introduced by the author; and I have specially striven to meet the wants of English students. The language has been condensed, the notation and nomenclature have been modernized, the arrangement has been simplified. The consideration of rare inorganic bodies and of organic bodies has been deferred to the latter part of the volume, where a section has been devoted to each, The grouping of

the metals has been harmonized with the course of analysis. The course of analysis has been simplified in description, and the preliminary examination has been curtailed. Analytical tables have been added at the end, which include the preliminary examination and the detection of metals in soluble mixtures."

The improvement is material in the arrangement for the analysis of mixtures of salts, most of the tiresome references to other pages having been avoided.

The section on the detection of the alkaloids continues to be an extremely valuable part of the work.

Turning now to the Quantitative Analysis, we find that Mr. Vacher has been very busy indeed with the pruning knife. He has, in fact, cut it down in the fifth edition to half what it was in the fourth edition. This act has our entire disapproval. A treatise on quantitative analysis, if well arranged and composed of processes tested by its author-and such is that of Fresenius-cannot be too full in its details. It is not intended for systematic study, except at the laboratory bench, and there every suggestion for the accurate execution of a chemical operation is welcome, and likely to save the disappointment of getting unsatisfactory results after the performance of tedious operations. Mr. Vacher has omitted many quantitative methods and innumerable reminders and precautions in the execution of those retained, and in doing so he has greatly lessened the value of the work. If, however, we suffer by his editorial zeal in one direction, we gain in another; and in what we have presented to us in the present edition, the improvements and additions are not few. We trust that in the sixth edition we shall see a tendency to restoration and preservation of what is good in the experience of chemists, rather than one of elimination and destruction. We would also ask for a return to the much more convenient page headings in the previous editions of both the Qualitative and Quantitative treatises; and further, for more detailed "contents" and indexes.

Notes for Students in Chemistry; being being a Syllabus of Chemistry and Practical Chemistry. Compiled from the Manuals of Gmelin, Miller, Fownes, Berzelius, Naquet, Gerhardt, Gorup-Besanez, &c. By ALBERT J. BERNAYS, Ph.D., F.C.S., Professor of Chemistry and Practical Chemistry at St. Thomas's Hospital. Fifth Edition. London: John Churchill & Sons. 1870.

PROCEE

ROFESSOR BERNAYS has performed for one in his posi tion a very humble labour. He has compiled a note-book for students, from the "manuals" issued by other chemists in similar professional positions to himself. For our own part, we wish he had spent the time he must have devoted to this labour to something more beneficial to the interests of the science he professes, and more serviceable to the student. Some persons believe in the usefulness of such a book as this, as rendering note-taking

by the student unnecessary. With these we cannot agree. Few would say that a student could learn chemistry from such notes alone to be useful, it is admitted they must be read in connection with attendance on a course of lectures, or at least with the reading of fully written works on the subject. But when thus used even, we are more than sceptical as to their utility. To acquire anything more than a verbal knowledge of his subject, the student must go through the mental process of taking notes as he goes along, whether he commits them to paper or not. He must think as he listens or reads, and form conceptions, and follow out trains of reasoning. In doing this, he takes notes, and to supplement the imperfections of memory, it is well for him to write them down as he takes them. No one can think for him, and therefore, in our opinion, no one can take notes for him. Teachers, and text-book writers, can assist his studies immensely, by furnishing him with a methodical summary of the leading facts and doctrines of the science, but then these summaries must be clearly and fully written, and complete in themselves. Such assistance Notes for Students cannot afford. At least we think so, and for the

reason we have stated. For the information of those who think otherwise, we must, however, say something as to the merits of this little note-book as such. It is a very full compilation, and exhibits evidence of both the industry and the care of the writer. The fifth edition is a great improvement of the fourth. The new notation and nomenclature are now exclusively used. We notice additional notes in apparently every paragraph in the book, and a close revision of the whole. The matter has been subtracted from as well as added to, but still the work is considerably enlarged. We have said that the author has performed a very humble labour; we will now add, that he has done it without ostentation, for though he has made such numerous emendations and additions in this edition he makes no mention of anything he has done in the preface to it, the first edition, by the way, that he has treated to a preface at all. In conclusion, let us express our conviction that Dr. Bernays has worked earnestly to aid the student, and our hope that his exertions receive a due appreciation from those who are able to benefit by them.

BIBLIOGRAPHY.

ENGLISH.

Gordon's Remarks on Army Surgeons, &c. Cr. 8vo. 5s. cl.
Norton's Causes, Prevention, &c. of Infantine Diseases. 2s. 6d. cl.
Pallett's Miller's, Millwright's, and Engineer's Guide. Cr. 8vo. 12s.
Ward's First Lessons in Inorganic Chemistry. 12mo. 2s. cl.

FRENCH.

Cryptogames vasculaires (Fougères, Lycopodiacées, Hydropterydées, Equisetacées) du Brésil. Par A. L. A. Fée, Professeur de Botanique à la Faculté de Médecine de Strasbourg, avec le Concours de M. le Docteur F. M. Graziou, Directeur des Jardins impériaux du Brésil à Rio Janeiro. Matériaux pour une flore générale de ce pays. Strasbourg et Paris. Berger-Levrault et Fils.

Etude de Météorologie médicale au point de vue des Maladies des Voies respiratoires. Par le Docteur R. Lahillonne. Strasbourg. Silbermann.

La Vie des Animaux illustrée ou Description populaire du Regne animal. Par M. A. E. Brehm. 17e et 18e Séries. Paris. J. B. Baillière et Fils.

Les Corps gras alimentaires. Le Lait, la Beurre, les Fromages, la production et l'industrie chez toutes les Nations. Par M. A. Robinson, Professeur de Chimie industrielle et agricole. Paris. Lacroix.

Notions d'Agriculture à l'Usage des Ecoles rurales et des Campagnes. Par R. Guillemot, Professeur d'Agriculture. Niort. Favre. Nouveau Guide de Geologie, de Minéralogie et Paléontologie. Par A. Pomel, Garde-mines-géologue. Rennes. Oberthur et Fils.

GERMAN.

Determinatio Orbitæ Cometa V., anni 1863. Dissertatio inauguralis. Von G. Valentiner. Berlin. Calvary und Co.

Die Entwickelung der Fieberlehre und der Fieberbehandlung seit dem Anfange dieses Jahrhunderts. Von Dr. Hirsch. Berlin. A. Hirschwald.

Flora von Deutschland. Herausgegeben von Dr. Schlechtendal, Dr. Langethal und Dr. Schenk. 22 Bände. Mit 20 colorirten Kupfertafeln. Jena. F. Mauke.

Handbuch der theoretischen und clinischen Percussion und Auscultation vom historischen und critischen Standpunkte bearbeitet. Von Dr. Niemeyer. Erlangen. Enke.

Lehrbuch der Augenheilkunde. Von Dr. Schelske. Berlin, A. Hirschwald.

Zur Ornithologie Brasiliens. Von Aug. von Pelzeln. Wien. Pichler's Witwe und Sohn.

Test for Hardness of Metal.-The hardness of metals, says the Builder, may now be ascertained by aid of an instrument invented by a French engineer. It consists of a drill, turned by a machine of a certain and uniform strength. The instrument indicates the number of revolutions made by the drill. From this, compared with the length of bore-hole produced, the hardness of the metal is estimated. It is said that a great proportion of the rails now employed in France are tested by this instrument,

CORRESPONDENCE.

It is distinctly to be borne in mind that we do not, by inserting letters, convey any opinion favourable to their contents. We open our columns to all, without leaning to any; and thus supply a channel for the publication of opinions of all shades.

No notice whatever will be taken of anonymous communications.
We cannot undertake to return rejected communications.

A METEOROLOGICAL PHENOMENON.-From G. DARWIN. SIR, -As I was travelling by rail on Saturday afternoon, at about half-past four, between London-bridge and New Cross stations, my attention was attracted to a very remarkable appearance in the sky. The sun was at the time very near to the horizon and was hidden by a dense wall of clouds, of which it only gilded the upper edge, but it was shining brightly on some light misty clouds, which were floating high aloft between the bank of clouds and me.

On a part of these light clouds I observed a kind of rainbow ver tically above the sun, and, as well as I could estimate, distant from 20° to 25° from it. This rainbow consisted of a bright spot, with two streamers issuing from it, which were inclined to each other at about 90°, or a little more, and pointed away from the sun, but were symmetrically arranged with respect to the vertical through the sun. The most accurate description which I can give of the shape is that it formed an equilateral hyperbola, with the convexity towards the sun, and the major axis passing through it.

The bow was broader than the ordinary one, but the edges were very undefined, and, except in the bright spot (i.e. the vertex of the hyperbola) the colours were not at all bright. This appearance only lasted for about a quarter of a minute from the time at which my attention was first attracted to it, and I was so intent on observing the form that, although I noticed that the colours were nearly those of the spectrum, and were arranged horizontally at the vertex, and I think ran longitudinally along the streamers, and not transversely across them, I did not notice which end of the spectrum was towards the sun. The appearance died away gradually, but in a faintly coloured spot which appeared about half a minute afterwards I noticed that the red was towards the sun.

The bow occupied about 15° of the heavens from the extremity of one streamer to that of the other. My first impression was that it was possibly part of the tertiary rainbow, which had taken this peculiar form owing to the shape in which the falling drops happened to be arranged; but in that case the colours must have been placed transversely on the streamers, and I think that an appearance so remarkable would have infallibly caught my attention. I conclude, however, from the account in Young's Natural Philosophy, vol. i. p. 443, of coloured halos seen in northern latitudes, that this appearance must have been a part of a system of halos. In fig. 431, pl. xxix. there is a picture of one of these systems, and part of this somewhat resembles what I saw.

As I have never come across any one who had seen such a thing, I suppose that such phenomena are rare in these latitudes. I send you this account thinking that it may be interesting to your readers. Your obedient servant,

AURORA BOREALIS.-From THOS. G. ELGER and JOHN J. HALL. SIR, On the evening of the 1st inst. another very remarkable aurora was observed here. The first indication of anything unusual in the appearance of the sky was noticed shortly after 7, when a phosphorescent white band, about 6° in breadth, could be traced from the horizon in the E.N.E., through e Ursa majoris and Cassiopeia, towards the west. It was at first only faintly luminous,

but rapidly increased in brightness, and spanned the sky from horizon to horizon; it then assumed the curtain-like aspect so frequently remarked during auroral displays in Northern Scandinavia, but which, I believe, is rarely observed in this country; at times it appeared to consist of well-defined bars of light parallel to each other, and directed towards the northern horizon. This band gradually died away, but was soon followed by others of a similar character; at 7.43 a fine belt of light passed through Aries and the square of Pegasus to the western horizon: it changed its form very rapidly, became contorted, and drifted towards the south.

Fainter bands were observed at intervals until 9. No appearance of auroral light above the northern horizon was noticed till about 7.30, when a glow was seen which gradually deepened and remained visible till nearly 10.

Between 8 and 9 I examined the light of this glow with the spectroscope, and saw one broad and tolerably bright line in the yellow, and very faint traces of light towards the more refrangible end of the spectrnm. I am, Sir, your obedient servant,

Bedford, Feb. 4.

THOS. G. ELGER.

SIR, A very beautiful aurora was observed here on the evening of Tuesday, the 1st inst., although by no means fully developed during my observation, and of comparatively short duration. From estimation I should say its position was from 25° to 30° south of the zenith, stretching for a considerable distance from E. to W. I am informed by a friend at the Kew Observatory (Richmond), that the photographic trace from the self-recording magnetograph showed considerable agitation of the magnetic needle. Your obedient servant,

St. Mary's Grove, Richmond, Surrey, Feb. 7.

JOHN J. HALL.

THE CHAIR OF BOTANY IN THE ROYAL COLLEGE OF SCIENCE, DUBLIN.

SIR,-As the investigation of science is necessarily the pursuit of truth, you will be glad to have the following corrections and annotations on your article on the above subject in the last number of your journal.

1. The Chair of Botany in the College of Science has a yearly endowment of £200.

2. You correctly give the history of the recent appointments. Both chairs held by Dr. Dickson became vacant on his succeeding Professor Walker-Arnott at Glasgow. The vacancy first filled up was that at Stephen's Green, by the appointment of Professor Wyville Thompson by the authorities at Kensington. Some time after, when the Board of Trinity College proceeded to fill up their vacancy, they appointed a distinguished alumnus of their own college, and rejected the occupier of the Stephen's Green chair. Thereupon Professor Thompson re turned to his chair at Belfast, which he had not resigned, and gave up his appointment at Dublin. The South Kensington authorities, in dealing with the vacancy thus created, confirmed the action of the Board of Trinity College in separating the chairs. It is thus obvious that your complaint should be directed against the authorities in Dublin, and not those in London. I have no doubt that the electors of Trinity College can defend their action; and indeed it is obvious that there is room for considerable difference of opinion as to the propriety of uniting the chairs.

3. If you recall Mr. Dyer's contributions to botanical science, you will, I am sure, acknowledge him to be a "distinguished," as well as an "industrious" botanist.

He is, with Dr. Trimen, conjoint author of the Flora of Middlesex, a work universally acknowledged to be a decided advance on any published County Flora.

With Professor Church, he has edited an American work, How Crops Grow; or, rather, he has re-written the Botanical portion of the work, as a comparison of the American and English editions show. This work, as far as its scope permits, contains the most recent and satisfactory exposition of physiological botany to be found in the English language.

He has translated an important memoir, by Miguel, on the Structure of the Seed in Cycadeæ, and has added to the published translation many valuable critical notes.

The smaller notices which he has published equally testify to his ability, and more than justify his appointment to the Chair of Botany in Dublin. I am, &c., F.L.S.

THE BROCKEN OF THE HIMALAYA.

SIR, A short time ago I learnt that, in a certain part of the Himalaya Chain (I cannot remember the exact name of the district), the phenomenon of the Brocken-the Brockengespenst-of the Harz Mountains is repeated with the addition of a halo, or rather a prismatic-coloured ring, completely surrounding the reflected image; and still further, that each individual sees his own reflection, while that of his companions is barely detected. Is not the former fact a singular one? and on what physical conditions can it be satisfactorily explained? With regard to the latter point, I have never heard such to be the case on the Brocken. J. B.

PERIODICITY OF SOLAR SPOTS.-From R. A. PROCTOR, B.A., F.R.A.S.

SIR, I cannot, on account of Mr. Elvins' kind expressions regarding myself, withdraw my protest against the tone of his last communication. In that communication (unwittingly I doubt not) he did commit the grave offence against scientific morality of presenting fancies as established facts. I hold the spread of true knowledge to be so important, that I make a rule of commenting in very definite terms of conduct of this sort. I should have done the same even though I had thought his opinions correct. No man has a right to describe opinions in terms applicable only to established facts.

As regards this part of my letter, then, there is nothing I can withdraw. It appears, however, that I was wrong in describing Mr.

Elvins' theory as 'vague guess-work." It has been "the result of years of patient toil." My excuse must be that no one could have suspected this.

Mr. Elvins' theory of comets exhibits such amazing conceptions respecting the laws of motion that I fear I shall hardly convince him of the yet more astounding absurdity of his explanation of the solar-spot period. Let me try, however. Passing over a number of other difficulties, each absolutely insuperable, save by ignoring the most obvious facts, I would ask him why the November meteors should drop into the sun. They do not come within 89,000,000 miles of him if they travel in the orbit calculated by Oppolzer for Tempel's comet, nor within 90,000,000 miles of him if Adams's estimate of their orbit is correct. So that they are about as likely to drop into the sun as the earth is or even less, since they travel far more swiftly past their perihelion than the earth travels in her orbit.

When Mr. Elvins has shown why the November meteors should leave the orbit assigned them by astronomers, in order to leap over the tremendous gap separating their perihelion from the sun, it will be time to dwell on other and equally egregious absurdities in his theory. Surely the difficulties Mr. Elvins has had to contend against-of which he says I" can form no idea "-can be no other than the powerful array of facts across which he has pushed both his theory of comets and his views as to the cause of the solar-spot period. Yours faithfully,

"WHAT ABOUT THE MAMMALIAN JAW?"-From
T. P. BARKAS, F.G.S.

SIR,-In an editorial note appended to a communication of mine which appears on page 73, vol. iii., SCIENTIFIC OPINION, you remark "If it were not exceeding our task as editor, we would express a hope that Mr. Barkas would prolong his researches on each specimen. He is always telling us of new discoveries, but he seldom tells us of any thing completely. What about the mammalian jaw ? "

With all deference to your opinion, Mr. Editor, it seems to me that the best course to adopt in bringing before the scientific world a description of discoveries in any department of palæontology is, first, to introduce facts, and then, when facts have become sufficiently numerous, deduce inferences. The greatest error into which any investigator into coal-measure paleontology could fall, would be that of drawing large inferences from very limited premises. The truly Baconian, and only safe method, is, in the first place, to accumulate well-ascertained facts, and, so far as coal-measure fauna are concerned, facts are just the things we most require. That will be evident when we learn that the majority of the fossil specimens obtained from the Northumberland and other coal-measures are obtained in a fragmontary condition, and that nearly all the coal-measure fishes of which we have anything like complete descriptions are Platysomus, Coelacanthus, Acrolepis, Palæoniscus, Acanthodes, Pygopterus, Amphicentrum, Rhizodopsis, and Megalichthys, and the approximately complete knowledge we have respecting them has been, to a large extent, derived from specimens obtained in the Permian and other strata, rather than from specimens obtained from the true coal

measures.

As an illustration of the incomplete knowledge possessed regarding moderately well-known coal-measure genera, I may state that little, perhaps nothing, is known of the genus Ctenacanthus, except that the fishes possessed curiously-formed spines; of Orthocanthus and Leptacanthus the spines alone are known, and the genera derive their names from the characters of their spines; much obscurity yet rests upon Gyracanthus, a cartilaginous fish, the spines of which are in almost every museum; and whether it had or had not teeth is not yet certainly established. Similar obscurity yet rests upon Pleuracanthus, the spines of which are common in our coal-measures. The teeth of Diplodus are supposed to belong to fishes which possessed the spines of Pleuracanthus, but of that there is no absolute certainty. The teeth of Cladodus are at present ascribed to two very different fishes, Gyracanthus and Ctenacanthus. Of Strepsodus nothing is conclusively known beyond the peculiar character of its teeth.

The forms or character of the fishes which have teeth known as Poecilodus and Pleurodus are unknown. Climaxodus may be a Ray or a Cestraciont, the matter is as yet quite uncertain, as a moderately complete group of the teeth has not yet been found. The teeth known as Ceratodus may probably belong to Ctenodus, the generic distinction being far from established, and recognized facts point in an opposite direction. Ctenoptychius is probably a tooth, but, so far as I am aware, the supposed teeth have never been found in situ on the jaw; they vary much in character, some having but five denticulations, and a newly-discovered specimen now before me possesses sixtysix denticular ridges. Upon nearly all the fishes known to belong to the coal period much obscurity prevails, except those on the list first enumerated, and respecting them much information has yet to be

Feb. 9, 1870.]

obtained before our knowledge of them can be recognized as approximately complete.

Of the reptiles of the coal period less is known than of the fishes, and to so slight an extent has the investigation of the reptiles of the Carboniferous era been prosecuted that no work on the subject at present exists. The information which has been obtained is scattered throughout various serials; some of the chief museums in the kingdom contain but a limited number of specimens of Palæozoic reptiles, and from other large museums they are entirely absent.

The latter statement is amply verified in the preface to the Index to the Fossil Remains of Aves, Ornithosauria, and Reptilia contained in the Woodwardian Museum of the University of Cambridge. The venerable Dr. Sedgwick, on p. vi. of his prefatory notes, says "of paleozoic reptiles we do not possess one single British specimen."

With these facts before us I think you and your readers will probably agree that I have some justification in detailing isolated palæontological facts without basing upon them merely hypothetical inferences, so long as for the most part mere fragments of fishes and reptiles come into my possession.

Hasty generalization is far more reprehensible than is the lower labour of truthfully presenting details, and, besides, the presentation of such details, especially when the specimens described are freely at the service of any paleontologist, will afford investigators in our own or other coalfields, the means of comparing the specimens they find with those that have been found elsewhere, and by such comparison much required information may eventually be obtained.

Taking Strophodus as an illustration, several teeth that have been ascribed to various species of that genus have by the discovery of the complete oral armature of Strophodus been proved to belong to one fish, and what were previously recognized as many species, have had to be discarded from the records of science. You will, I trust, Mr. Editor, now see that it is practically impossible to describe many coal-measure fishes completely, and if I clearly describe the new specimens that are found, I at least increase the knowledge of details upon which the superstructure of true science will have to be built.

You ask "What about the mammalian jaw?”

The mammalian jaw is yet in my possession; it is the only jaw of the kind I have yet found or seen, and I believe it is the only jaw of the kind that has been found or seen. The cabinet of Mr. Ward, of Longton, is rich in jaws of fishes and reptiles, but nothing like the supposed mammal jaw is in his possession; and the same is true of the collections possessed by Messrs. Sim, Taylor, and Campbell, of West Cramlington. The jaws of Acanthodopsis have been referred to as being similar to the unique jaw in my possession, but in reality it bears no resemblance to the jaws of that little understood fish. The upper jaws of Amphicentrum more closely resemble it, but the contrast is so marked that the most casual observer can recognize the difference between them. Whatever the jaw is, it is evidently unlike all that have yet been described, and I believe all that have been discovered. The jaw has been seen by several gentlemen eminent in paleontology, and with one exception they acknowledged that it presents mammalian characteristics. It has not yet been seen by any paleontologist who makes comparative odontology a speciality, but I trust, on an early occasion, to have an opportunity of submitting the specimen to one or more of the best odontologists in the kingdom, and whatever their opinions, whether for or against the conclusions at which I have provisionally arrived respecting the fossil, your readers shall be made acquainted with them. I am merely desirous of ascertaining truth, not of supporting an assumed infallibility, which I neither claim for myself nor am prepared to allow to others.

EMASCULATION IN ANIMALS.-From LAWSON TAIT.

SIR, Would you allow me, through your columns, to request urgently that any one who may be in possession of facts, well authenticated, bearing on this subject will record them? It is scarcely possible to exaggerate the importance of such a fact with regard to many questions now at issue. For instance, what a valuable fact it would be for Darwin!

May I suggest that correspondents give their names and addresses? because, otherwise, their contributions may be altogether valueless. Wakefield, Feb. 3. I am, &c., LAWSON TAIT.

NEGATIVE EVIDENCE IN GEOLOGY. SIR,-Your correspondent "A Young Beginner" has employed his time and opportunities well, and has no doubt read much and carefully. He has forcibly expressed, by ample quotations from recognized authorities, the case of that school of geologists who (unfortunately as I think for the progress of science) have allowed absence of knowledge to take the place of knowledge. All the arguments and opinions

adduced by your correspondent were long ago brought forward to prove that the human race was of recent introduction, that mammals and birds were tertiary only, that reptiles did not exist during the paleozoic period, that fishes commenced with the carboniferous series, and that none but animals of low organization lived during the earliest fossiliferous deposit. Each assumption has in turn been disproved by facts, but the old feeling remains: We have, then, not found them; therefore they are not to be found.

area.

Allow me to point out to your correspondent, and to your readers interested in this question, that the space occupied by paleozoic rocks on the present surface of exposed land is exceedingly small in comparison with the earth's surface, and that the localities hitherto examined successfully for fossils bear no large proportion, even to this So large a part of the earth's surface is now withdrawn from the possibility of receiving more than accidental indications of the characteristic inhabitants of the land, that if the present land were submerged, and the sea bottom raised into land over the whole earth, the chances of discovering such indications would be infinitely small. The same argument applies to the littoral and shallow water as to those found in deep sea, for these, in most cases, would be almost barren, or would only contain remains of marine organisms. Shores and shallow water are not necessarily connected with inhabited land. The mere fact that we have found in the middle of the Oolites, in one very limited deposit, a few bones of minute quadrupeds, nowhere repeated in the vast and rich areas of secondary fossiliferous rock, is of itself proof of the rarity of the conservation of such fossils. No rock is more promising in this respect than the Stonesfield slate. We know that the conditions were in the highest degree favourable for receiving and retaining remains of land animals: we know that such animals were present not far off. And yet no bone of mammal, and only one fragment of a warm-blooded animal of any kind, has been found in them.

In spite, then, of high authority, and in opposition to the craving for generalization, so natural and so useful in its way, I hold that it is more logical and more philosophical to be cautious and wait for facts, than draw conclusions from ignorance. I neither affirm nor deny that the Eozoön was the first animal, and the Lower Laurentian rocks the first fossiliferous deposits; but I do say that, on the one hand, I am a little ashamed of the number of protos and cos and palæos that I find in geological nomenclature; and that, on the other hand, an admission of there being still something more to be learnt about the earth's early history is one that none of us need be ashamed of.

AN OLD STAGER.

SCIENTIFIC SOCIETIES.

Secretaries of Societies will oblige us by regularly forwarding "Abstracts of Proceedings; and they would do much to enhance the interest and success of their meetings if they would enable us to publish in anticipation "notices of papers to be read,'

ROYAL SOCIETY.

THURSDAY, JANUARY 27TH.-The following paper was read:"Observations on, the Temperature of the Strata taken during the sinking of the Rose Bridge Colliery, Wigan, Lancashire, 1868-69," by Edward Hull, M.A., F.R.S., Director of the Geological Survey of Ireland. In an elaborate paper by Mr. W. Hopkins, entitled "Experimental Researches on the Conductive Powers of various Substances," published in the Philosophical Transactions for 1857, an account is given of a series of experiments made under the general supervision of Mr. Hopkins, F.R.S., himself, and Mr. W. Fairbairn, F.R.S., during the sinking of the Astley Pit of Dukenfield Colliery, in Cheshire.1 At the time this paper was written, the depth attained was only a little more than 1,400 ft.; and the rate of increase between the depths of 700 ft. and 1,330 ft. was found to be 1° F. for about 65 ft. These observations were subsequently continued until the pits had attained their full depth of 717 yards from the surface. The last observation made was in the shale overlying the coal-seam, known as the "Black Mine," which it was the object of the proprietor, Mr. Astley, to reach, and the temperature was found to be 75° F. Assuming the "stratum of constant temperature," or, as it is also called by Humboldt, "the invariable stratum," to be that which was reached at 16.5 feet with a temperature of 51°F., the total increase of temperature would amount to 24° F., giving as the rate of increase 1° F. for every 88.925 ft. This is much below the average rate of increase. During a part of the period above referred to (from 1854-56) another coal-pit was being sunk at Wigan, which reached the depth of 600 yards, down to the celebrated "Cannel Mine." At this pit similar

1 The entire series of these interesting observations were kindly supplied to me by Mr. W. Fairbairn, and are published in The Coalfields of Great Britain, 2nd edit. p. 226.