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removed from the microscope. His previous book on Physiological Histology has, however, shown the connection between the two. The fixing action of preservatives on tissues, the staining reactions of cells and nuclei, are ultimately chemical in nature, and much of macro-chemistry can be learnt from microchemistry. Dr. Mann's sympathies are mainly physiological, not anatomical. Physical chemistry also is more than a hobby with him, and the sections relating to speculations of a physico-chemical nature form pleasant oases in what as a rule is rather solid reading. His histological proclivities have led him in some cases to devote a good deal of space to subjects which some might regard as of secondary importance -for instance, his lengthy description of the interactions of proteids with mercury compounds evidently springs from the extensive use he has made of corrosive sublimate as a fixative.

Cohnheim's book in the original state cannot be described as an ideal one. It lacks the imaginative faculty, and reflects the stolid, plodding German worker, anxious to omit no reference to literature that can possibly be dragged into a footnote. To some investigators this is of course advantageous; they will profit by the diligence of the author, and easily be able to consult the memoirs quoted in reference to any special point they are interested in. But to the student who desires to obtain a general insight and a wide outlook on the general relationships of the subject, this compression of material is a distinct hindrance; he will be apt to lose sight of the wood on account of the trees.

Dr. Mann follows on very much the same lines, and though it is impossible to restrain one's admiration for his labours in hunting up literature, quoting authorities as far back and as far forward as possible, one cannot but regret that the text does not as a consequence run easily, and most of it will form stiff reading even for advanced students. In some places the pages abound with chemical formulæ without a sufficient guidance in words. Here, again, anyone but an accomplished organic chemist will have difficulty in finding his way along.

Dr. Mann also has certain mannerisms of style, but one does not complain of these unduly, for they stamp the pages with the author's individuality; but there is one of these faults which many will find annoying and even confusing, and that is a looseness and inexactitude in the use of terms. For instance, on the title-page we find the word "proteid" used as a general expression for all the albuminous substances; within the pages of the book "proteid" is employed only for a certain group of these materials. Albumin also is sometimes used as a generic term, and at other times applied to a specific group; sometimes it is used as opposed to globulin, sometimes it includes the globulins, and sometimes it includes everything. In one place we read that lactalbumin is one of the few true albumins; on another page it is alluded to as a hypothetical substance. The author has dedicated his work to his father, and in the dedication tells us something of his father's lifework. It would be interesting to know something

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The same kind of carelessness is shown in the spelling. Albumin is sometimes spelt with an i, sometimes with an e. The nomenclature committee of the Chemical Society tried to introduce uniformity into spelling, and assigned certain meanings to certain terminations. A word ending in ine, for instance, means an alkaloidal material; a word ending in in does not; similarly, the terminations ol and ole have a distinct chemical significance. But Dr. Mann has paid no attention to such rules. "Vitellin," for example, is sometimes spelt with, sometimes without, a final e. "Gelatine" and "cholin" are spelt as just printed in direct contravention of the rules of the Chemical Society. The names of investigators are also often mis-spelt; Waymouth Reid, Curtius, Claude Bernard, and Lane-Claypon are among the


The whole question of nomenclature in chemistry is very difficult, especially in translations. It is hopeless to try to reconcile English with German usages, but there ought to be an attempt on the part of English writers to adopt some sort of uniformity. This difficulty is accentuated in relation to proteid nomenclature, and one can only hope that the joint committee of the Physiological and Chemical Societies now sitting on this very subject may put forward some practicable suggestions. Dr. Mann is therefore not wholly to blame for his misdeeds.

In spite of the blemishes to which I have devoted so much space, I believe the book will have a useful career in front of it. Its many excellences can be discovered by reading it and using it, and Dr. Mann is to be congratulated in having produced such a valuable addition to scientific literature.


W. D H

STATISTICAL SEISMOLOGY. Les tremblements de terre. Géographie Séismologique. By Comte F. de Montessus de Ballore; with a preface by Prof. A. de Lapparent. Pp. v+ 475. (Paris: Armand Colin, 1906.) Price 12 francs. WITH the growth of their science seismologists have become more and more specialised, and devoted themselves to the cultivation of a limited portion of their domain, but none have marked out for themselves a more clearly defined plot, or culti vated it with greater assiduity, than the Comte de Montessus de Ballore. Leaving to others the study of the nature and effect of earthquakes, he has confined himself to the consideration of their cause, and attacked the problem by the statistical way, believing that a detailed study of the distribution of earthquakes in time and space will most conclusively indicate their cause. By no means the first cataloguer of earthquakes in point of time, for the great lists of Mallet and Perrey are well known, to say nothing of the numerous local catalogues compiled by others, our author stands preeminent in the number of earth

quakes which he has tabulated, and the work before us deals with the records of 171,434 distinct shocks. The labour involved in this compilation would have formed no light task for any man, and when we remember that, besides being a specialist in seismological statistics, the author is an officer on the active list of the French Army, the result seems almost miraculous.

In summing up the results of all this compilation the author holds that he has conclusively established the independence of earthquakes and volcanoes, and the greater prevalence of the former along those tricts where the surface relief shows the steepest and longest gradients. Both these conclusions had been reached by Prof. Milne while working in Japan, and the second of them is only an empirical, and not invariable, way of expressing the general principle that earthquakes are most abundant where the crustmovements have been greatest and most recent, while they become rarer as these movements are older and have more or less completely died out; but we must remark that earthquakes seem to be more particularly associated with the changes resulting from, or accompanied by, compression, for the dropped valleys of the Jordan, the Red Sea, and of Central Africa are not specially affected by earthquakes.

Comte de Montessus attempts to carry his conclusions still further, and finds that earthquakes are almost confined to certain bands which correspond with the secondary geosynclinals of Haug, and are said to lie along two great circles, making an angle of 67° with each other. We have had the curiosity to plot these bands, as shown on the map accompanying the book, upon a globe, and have failed to find any correspondence between them and the great circles as defined, or, indeed, with any other great circles; approximately, they seem to form a network of arcs of great circles, joining up in groups of three and four, an interpretation which is more probable than the other, though the departures in detail render the correctness of either view doubtful. However this may be, the fact remains that nine-tenths of the shocks recorded have originated in regions which cannot cover more than one or two per cent. of the globe and are almost all distributed along certain lines, of which the most important are the great girdle of the Pacific, the line which runs up from the Sunda Islands, through Arracan, the Himalayas, Caucasus, and Alps to the western Mediterranean, and another which runs up from the Caucasus through the mountains of Central Asia to Lake Baikal, possibly continuing to somewhere in the neighbourhood of the Bering Straits.

Though, in the main, the distribution of the more Violently shaken regions shows no change from that drawn by Mallet in 1858, there is a radical difference in the character of the two maps. In Mallet's the frequency of earthquakes was indicated by the depth of tint, and the dark patches shaded off gradually into the white; de Montessus, believing that it is a mistake to treat an essentially discontinuous phenomenon as a continuous one, has made the limited areas, where destructive earthquakes are known to

originate, black, and left the rest of the map blank. This abrupt boundary between the regions classed as seismic and the much more extensive ones classed as peneseismic or aseismic, is held to be a better representation of what is actually the case than any gradual shading of the one into the other. The difference between the two maps is, in fact, one of principle; Mallet's was meant to indicate the frequency with which earthquakes were felt, that of de Montessus the frequency with which they originate. Each of these facts is interesting in itself, but their delineation must necessarily differ, apart from any question of increasing perfection of the data.

We have indicated some of the conclusions drawn in this book, which do not seem to be so fully established as its author suggests, but this must not be taken in derogation of the value of his work in statistical seismology. We welcome this summary of his researches, and regret that he should have followed the custom, so common in France, of omitting a subject index.


Notes on Shipbuilding and Nautical Terms of Old in the North. By E. Magnusson. Pp. 62. (London: A. Moring, Limited, 1906.) Price Is. net. Viking Club Society, and its appearance will be THIS small volume reproduces a paper read before the welcomed by all who are interested in the history and development of shipbuilding. Although it deals chiefly with Scandinavian records and discoveries, it contains an excellent summary of Greek and Latin references to ancient ships, and does not leave unnoticed much older Egyptian types. In short it is a scholarly performance, and the writer has a full appreciation of technical developments which have accompanied progress in shipbuilding. Wide reading and research must have been undertaken to provide the materials; they have been dealt with in a terse but clear style, and the result is of permanent value as a book of reference and a bibliography of the subject. An excellent glossarial index is appended. The only regret one feels is that there are no illustrations. The rock-carvings of ancient ships found in Egypt, Sweden, and Norway are described and compared; but simple illustrations would have emphasised the deductions made by the author. Again, the details of methods of construction which Mr. Magnusson gives are readily understood by experts in shipbuilding, but would be grasped by general readers also if diagrams of a simple nature had been given. The ancient ships found in Scandinavia and preserved in museums might also have been pictured with great advantage. Of coursesize and cost would be increased if this were done, but that action is well worth the consideration of both author and publisher, as the permanent value of the book would be greatly increased thereby, and its place in the libraries of all interested in shipbuilding would be assured.

A book so condensed in form and substance must be read to be understood. Mr. Magnusson does not claim originality in discovery or treatment. He starts with the log and raft of the stone age, passes to the canoe hollowed from a single log by the use of fire and flint implements; traces the development of the coracle and other hide-covered vessels, with internal framework; shows how these "skins were replaced by wood planks, first fastened by thongs or withes,

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and later on by iron nails; and so he arrives at methods of building which persisted, with trifling variations, until wood gave place to iron in the last century. As regards propulsion a similar advance is traced from the single oar, to the rowing boat, and the galley with its banks of oars, coming at last to the use of masts and sails, as navigation took a wider and over-sea range. The special provisions made in vessels used for purposes of war are described, including that most ancient method of attack-the ram-bow. Altogether the book is an excellent piece of work.

W. H. W.

A First German Course for Science Students. By Prof. H. G. Fiedler and F. E. Sandbach. Pp. x+99. (London: A. Moring, Ltd., 1906.) Price 2s. 6d. net.

IT is essential that students who intend to devote serious attention to science should be able to read scientific works in French and German, and, if possible, also in Italian. By the use of the present book a working knowledge of the German language can be obtained through lessons based upon work in elementary physics and chemistry. The book consists of a series of reading lessons describing simple experiments and principles such as are included in the rudimentary courses of schools. The words and phrases used in the various reading-passages are graded in such a way that the principal rules and grammatical forms are illustrated by the text. A short outline of grammar essential for the purpose in view follows the series of lessons, and there is a full vocabulary.

The book is printed in English characters, but the text and illustrations have a decidedly German appearance, as is appropriate in this case. Though the course covered by the lessons is similar in substance to that taken as introductory science in many schools, no doubt most teachers will prefer to follow English text-books for the actual work of the class-room and laboratory, and to use this book as an auxiliary aid or an incentive to the study of German. For pupils who are familiar with the experiments described, the book will be found very useful, and it will make them acquainted with the German equivalent of many technical terms not to be found in the ordinary reading books of the language. As an attempt to coordinate the teaching of modern languages and science, it will no doubt be appreciated, and for the finer feeling of literature pupils may still read extracts from the works of standard authors.

Personal Hygiene Designed for Undergraduates. By Dr. A. A. Woodhall. Pp. vii+221. (London: Chapman and Hall, Ltd., 1906; New York: John Wiley and Sons.) Price 4s. 6d. net. PERSONAL hygiene is an important branch of hygiene which does not receive its full measure of treatment in any text-book, but this small work does not pretend to offer to its readers more than a clear and elementary statement upon the hygienic needs of the body. It is intended for undergraduate students, and it consists of the substance of lectures upon personal hygiene delivered by, the author during the past few years. Exercise, food, clothing, habits, and similar matters of daily individual concern, are here dealt with in language as free from technical terms as possible. We are told in the preface that the constant aim of the writer has been to present actual conditions in the simplest language, and it must be said that he has achieved this object. We may add that the work is free from "Americanisms "-either of wording or spelling.

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The chapters on alcohol, tobacco, and exercise are particularly good. They are discussed in tolerant language and with much sound common-sense. After reading the following opinion (p. 157) the reader will think twice before he refuses an offer of confectionery. Where the taste has not been vitiated, in a degree by tobacco but chiefly by alcohol, sugar is as acceptable to the normal civilised man as it is to savages, and his disposition toward candy is no bad test of his drinking habits."

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The following criticism of our national game o cricket will scarcely meet with approval in this country :-" Cricket, an exotic that has never taker wide root on our soil, lacks many of the qualities of a good game, chiefly because of the long waits before going to the bat and the limited number actively engaged." But though the author does not write in his usually well-informed manner upon this particular item, the following statement (p. 88) will serve to acquit him of the charge of bias towards every thing American :-" The misnamed nasal twang with which some Americans are justly charged is due partly to chronic catarrh, blocking the nasal passages, and pa.tly to that curious and unconscious imitation by which in youth we acquire the tone most commonly heard. Unfortunately, as a people all our voices are too sharp and rasping. .. We are so accustomed to strident voices that we fail to recognise their inherent infirmity."

Life and Matter. A Criticism of Prof. Haeckel's "Riddle of the Universe." By Sir Oliver Lodge. Pp. ix + 200. (London: Williams and Norgate, 1905.) Price 2s. 6d. net.

Ir is difficult to pardon Prof. Haeckel for his dogmatism and his over-statements, and no less for his having furnished the peg on which have been hung many dull books and reviews. Forgiveness becomes easier when his work evokes a first-rate criticism like that in the volume before us. Sir Oliver Lodge contests chiefly (a) the right by which the name of Monism is arrogated to the Haeckelian philosophy; (b) Haeckel's statement of the "Law of Substance, the true account of which, according to the critic, is that "anything which actually exists must be in some way or other perpetual "; (c) Haeckel's account of the development of life, and particularly the theory which endows the atoms of matter with life, will and consciousness.

The later chapters of the book state with great clearness Sir Oliver Lodge's own constructive views. He regards it as possible that life is a basal form of existence, as fundamental an entity as matter and energy. "It can neither generate nor directly exert force, yet it can cause matter to exert force on matter. and so can exercise guidance and control." His view occupies a middle position between the so-called monistic one and that, for example, of Prof. James Ward, who argues that the laws of physics are only approximate and untrustworthy.

The author, who understands well that effective illustration is half the difficulty, and that the "analogy of experience" is one of the soundest of philosophic principles, develops a fascinating comparison between life and magnetism. If we understand his views aright they imply that possibly mind can exist apart from terrestrial brains, and life apart from living creatures or plants as we know themthat is, that the phenomena of life and consciousness

which surround us are due to the interaction of something material and something spiritual, or (to express it otherwise) to the fact that something spiritual uses the material as its instrument or organ. This seems to imply a dualism, but he also holds it possible that "there may be some intimate and necessary connection between a generalised form of maiter and some lofty variety of mind."

The arrangement of the various topics is not always the best possible. This is partly caused by the inclusion of reprints from well-known journals-a practice which is open to criticism. But apart from these slight defects the book deserves hearty commendation.

The Fox. By T. F. Dale. (Fur, Feather, and Fin Series.) Pp. xiii +238; illustrated. (London :Longmans, Green and Co., 1906.) Price 5s. "THE FOX," writes the author in his opening paragraph, is at home in Europe, Asia, including India, a great part of Africa, the whole of North America, and a distinct but allied species, Canis virginianusknown as the grey fox in the United States-is found in South America." If he had tried to compress as many errors as possible into a single sentence, he could scarcely have succeeded better. The fox is unknown in India proper, it inhabits only the northern fringe of Africa, and the grey fox (Urocyon cinereoargenteus) is a native of North and not of South America. This is one of those numerous instances where authors of works on popular natural history will go out of their way to refer to subjects which they do not understand, and which do not concern them. Had Mr. Dale kept within his proper limits, we should have had nothing but commendation to bestow upon his work, in which the fox is discussed from the point of view of the sportsman and the farmer in a very thorough manner. The eight illustrations by Messrs. Thorburn and Giles are all that can be desired, although one of them follows somewhat closely on the lines of a well-known sketch by the late Mr. Wolf. R. L. Oologia universalis palæarctica. By Georg Kause. Part i. (Stuttgart: Fritz Lehmann, Verlag; London: Williams and Norgate.)

Tins is the first part of a beautiful egg book, printed entirely on separate sheets of cardboard, two sheets being devoted to each species-one of coloured figures of the eggs, the other of letterpress, backed with references to the specimens figured. The text is in German and English, and comprises a large number of synonyms and local names, and a short description of the range of the bird, its breeding habits, nest, eggs, &c. The four species treated of in the first part are the golden eagle, quail, song thrush, and raven, as many as sixteen (odd) eggs of the last-named bird (from different localities) being figured. In the case of the song thrush we have five "clutches," and in that of the golden eagle a clutch of two eggs and three single ones. The colour printing has been very successful, and admirers of eggs will welcome the excellent selection of varieties which has been figured, of each of which the "data are given. We cannot extend the same praise to the English version of the letterpress, which is crude, too literal, and disfigured by unfamiliar words and expressions. However, it is possible to understand what is meant, although the remark on the quail that "the only breeds, the male is polygamons," reads strangely until we substitute broods for breeds and correct the misprint.

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The work is to be complete in 150 parts, and Messrs. Williams and Norgate point out that on the publication of Part ii. the price per part will be raised from fifteen to eighteen pence.


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

Osmotic Pressure.

IN the concluding sentence of his most interesting letter on this subject in your issue of May 17 (p. 54) Mr. Whetham states that "The theory of ionic dissociation rests upon electrical evidence, and by such evidence it must be tried. It is unnecessary to dwell on the importance of the pronouncement.

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Will Mr. Whetham kindly tell us how we know all the things which-in the final paragraph of his letter-he so confidently asserts that we know; in fact, what precisely the electrical evidence is upon which the theory of ionic dissociation now rests. He is a recognised master of lucid exposition and will be able, I am sure, as counsel of the whilom advocates of the doctrine of molecular suicide in

solution, to state the case fully and fairly on their behalf. When we have this statement it will perhaps be possible to consider the validity of his modest contention and whether electricians alone have the right to pronounce judgment. A plaintiff is usually sure of his case before his cross-examination takes place.

This request is preferred in no adverse i(r)onical spirit, should be informed where we are exactly. Our friends the simply because I feel that it really is necessary that we ionic dissociationists are incorrigible squatters and seem to their adversaries' property; it is difficult to know, as they think that they have acquired the right of preemption over object to stock-taking, whether they have given anything in exchange for that they have lifted and what they have jettisoned of their original property; and until the electricians' title-deeds are shown and submitted to careful

scrutiny, chemists can scarcely be expected to admit that they are ousted from possession.

As a chemist and a friend of the poor molecules, I feel that the aspersion of immorality should not be allowed to rest upon them for ever unless the evidence be really condemnatory beyond question. In any case, it is important that we should discover the true nature of the crime committed in solution; to cloak the inquiry by restricting it to thermodynamic reasoning-a favourite manoeuvre of the mathematically minded-is akin to using court influence in abrogation of full and complete investigation; such a chemist, who, although able, perhaps, to imagine the exist course may satisfy the physicist but is repulsive to the ence of a frictionless piston, yet desires, in the first place, tangible piston of practice. to get nearer to a knowledge of what happens to the real HENRY E. ARMSTRONG.

MR. WHETHAM's letter in NATURE of May 17 (p. 54) raises clearly the whole question of the applicability of thermodynamic reasoning to osmotic phenomena. As my views as to the value of thermodynamic reasoning appear to be somewhat heterodox, may I indicate some criticisms of his remarks?

All thermodynamic proofs assume the truth of the "second law." Now the machinations of Maxwell's demon have shown clearly that the meaning of this law, when interpreted in terms of the molecular theory, is merely that, in the processes considered, no differential treatment is applied to the molecules in virtue of their different velocities. The law may or may not be true in any particular case. It cannot be said that there is any a priori support for it, or that a proof of its validity for one small branch of phenomena would justify its application to a totally different branch.

In all treatises with which I am acquainted, when the law has been stated, the only reasons alleged for believing it to be true are those derived from our inability to construct a heat engine which will work without equalising temperature. A few pages, before or after, will be found the statebut it is not pointed out that the irreversibility of all actual ment that we cannot construct a reversible heat engine; engines would mask the effect of a violation of the second law, unless that violation were very complete and the separ

ation of the molecules into high and low velocity groups very nearly perfect. A demon might be slaving with the most commendable energy, but all his exertions would be rendered inoperative by the imperfections of our apparatus. To my mind, the evidence for the second law, even applied to the best actual heat engines, is extremely slight.

But even if the evidence were overwhelming, there would be no justification for applying the law to a process of such an entirely different nature as osmosis, where, moreover, there is some presumption that it is not true. No actual membrane is perfectly semi-permeable; some molecules of the solute pass through; it is not wildly improbable that these molecules possess velocities within some narrow range. But if this is so, Maxwell's demon is at work, the second law is not applicable, and thermodynamic reasoning is absurd. Definite experimental proof must be offered before the validity of the law for osmosis can be considered even probable. Some progress might be made by examining the same membrane at different temperatures; if its degree of imperfection "did not vary rapidly with the temperature, the existence of such a separation as has been suggested would be rendered less probable.

Mr. Whetham has offered some proof already. He points out that there are five assumptions involved, and asserts that the truth of all of them is proved by the agreement between theory and experiment. But he ignores the possibility that two or more of the assumptions may be incorrect and that the errors thus introduced may cancel each other. He offers a particular solution of an equation containing five variables, and assumes that it is the only solution possible.

It must be remembered that there is not perfect agreement between theory and experiment. The errors are larger than those involved in the direct measurement of the pressure and the other quantities involved; there is a systematic error. But this is due, say the thermodynamicists, to the imperfection of the membrane. Exactly so; but that imperfection may invalidate the whole proof; in order to support their proof they may be denying one of their fundamental assumptions.


Mr. Whetham says that to reject the theory because there is no perfect membrane would be as absurd as to reject all thermodynamics because there is no reversible engine. I agree; but then I am such a heretic that I reject both. Our inability to construct a perfectly reversible engine is connected with the impossibility of handling individual molecules; friction and the rest vanish if we could replace the material cylinder by a swarm of trained demons. When we have constructed a perfectly reversible engine we shall be possessed of the powers of those demons, and we shall be no longer bound by the second law, which merely asserts that we do not possess those powers. So far as physicists are concerned, reversible thermodynamics is "" a vain thing.'

Neither am I convinced of the perfection of Mr. Whetham's two perfect membranes. They are doubtless perfect so far as the solute is concerned, but his assumption (2) may be violated by the molecules of the solvent. It is quite possible that it is the swifter molecules which escape in the vapour and the slower which escape into the solid, and that, if our experimental devices were sufficiently delicate, we could use the separation thus effected to perform useful work. At any rate, proof is required to the contrary before thermodynamic deductions can be made with accuracy.

So far as I can see, thermodynamic reasoning applied to osmotic phenomena, as to most others, proves nothing but that the sum of the errors introduced by the various rather doubtful assumptions is not very different from zero -a result that does not seem to me worth the labour that has been expended in obtaining it

NORMAN R. CAMPBELL. Trinity College, Cambridge, May 20.

The Oscillation of Flame Cones. PROF. GALLOWAY (NATURE, April 19, p. 584) considers that my explanation of the phenomenon described by Mr. Temple in his letter (March 29, p. 512) is inadequate, and he offers a different explanation. With the view of deciding the question some experiments have been made here by

Mr. C. E. Whiteley. I may perhaps repeat that the phenomenon in question is the continued descent and re-ascent of the inner cone of a coal-gas and air flame when a suitable mixture of the two is ignited at the end of a glass tube fixed so as to form a prolongation of the metal

tube of a Bunsen burner.

The following results were obtained by Mr. Whiteley :(1) The continued oscillation of the inner cone could not be established with a forced supply of both gas and air but only when the air was sucked in by the injector action of a gas jet, as in the ordinary Bunsen burner. (Mr. Temple informs me that this was also his method of working.) (2) The continued oscillation of the inner cone could be maintained when the apparatus was tilted even to horizontality or beyond. (3) When the inner cone began to descend a back pressure was immediately produced in the ascending current of gas and air.

I think the determining influence is clear from these observations. When the cone begins to descend and causes a back pressure this will momentarily check the indraught of air without materially checking the supply of gas. Ꭺ stratum of mixture containing less air is thus produced; its rate of inflammation is less than its upward velocity, and so the cone is carried to the top of the tube. Soon the normal air supply is re-established, a mixture with a higher rate of inflammation is restored, and the cone again descends.

A confirmation of this explanation is afforded by two further observations :-(4) a shortening of the glass tube increases the rapidity of oscillation in conformity with the shorter distance to be traversed by the altered stratum: (5) a capacity in the form of a globe at the bottom of the glass tube stops the oscillation. Such an arrangement would both damp the back-pressure impulse and obliterate stratification.


Observations (2) and (5) show, I think, that the chimney. like action suggested by Prof. Galloway cannot be the determining cause, and indeed this could hardly be expected, inasmuch as such action would increase the aspiration of air and produce a mixture having a higher rate of inflammation, a condition which would oppose the other effect, viz. the increased upward velocity of the mixture to which alone Prof. Galloway alludes.

My own previous explanation was inadequate to explain the continued oscillation, and only important in relation to the lighting back of Bunsen flames.

The University, Leeds, May 19.


Ancient Fire Festivals.

IN reference to your series of articles which have recently appeared in NATURE on Stonehenge and the ancient festivals, I send you the following notes on a Wiltshire celebration of the August fire customs. Tan Hill Fair is held on August 6, and the coincidence of the name Tan (Celtic for fire) and the date point to a time long prior to our era, when the fire festivals were annually held.

This fair, the origin of which is lost in antiquity, is held in the very last place likely to be chosen for such a purpose, and must have had its beginning at a time when men assembled there for some purpose very different to what brings them there now, for neither roads nor waterways (conditions essential to most fairs) lead to Tan Hill.

Tan Hill is on the highest part of the downs (near Devizes, north Wiltshire), 958 feet above sea-level, looking down on Avebury and dominating the whole country, and crossed only by British trackways which lead to the fair.

Sacred fires lit of old on this Tan Hill would have been seen from Martinsell (near Marlborough), Hackpen, Oldbury, and for miles around, and were probably eagerly watched for by the people taught to expect the blessing on the crops of the ensuing year consequent on these fires; and it is on this bleak. desolate down that one of the largest fairs of the country is held.

Fairs in Ireland and in Wales carry on the same tradition of the ancient fire festival held in August, as well as this one at Tan Hill.

In ancient Ireland this August celebration was called "the Lugnassad," the feast of Lug (a sun god), and according to Prof. Rhys "this festival was the great event

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