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THURSDAY, NOVEMBER 10, 1904. member of the Rhenish Medical College, was a person

of some importance in the city, and it was probably

in his house that the authors of this correspondence JUSTUS FON LIEBIG AND FRIEDRICH

first made each other's acquaintance. MOHR.

Coblenz, from its proximity to the French frontier, Monographieen aus der Geschichte der Chemie.

was the scene of many stirring episodes during the Herausgegeben von Dr. Georg W. A. Kahlbaum.

early years of the nineteenth century, and Mohr himviii. Heft. Justus von Liebig und Friedrich Mohr

self lived through the time of, and was personally in ihren Briefen von 1834-1870. Pp. viii + 274.

witness to, the rise and collapse of French military (Leipzig : Johann Ambrosius Barth, 1904.) rosius Barth, 1904.)


Price power during the interval between Moscow and Sedan. 8 marks.

As a little boy he might have seen the passage of R. KAHLBAUM continues to put those chemists the Rhine by the French troops on the occasion of

who are interested in the personal history of their | Napoleon's invasion of Russia, and have spelled out science under an obligation to him by reason of the the magniloquent inscription on the fountain before care and assiduity which he devotes to the editing of St. Castor which commemorates that event, as well as the letters of the great leaders of chemical inquiry the caustic words which St. Priest, the Russian comsuch as Berzelius, Liebig, Wöhler, and others, as these mander following on the heels of the retreating French, trort time to time come into his keeping. The volume caused to be added :-“ l'u et approuvé par nous. before us deals with the correspondence of Liebig and

| Commandant Russe de la l'ille de Coblence : Janvier Friedrich Mohr.

Ier 1814." As an old man he saw, after the debâcle Of Liebig it is unnecessary at this date to say any- l of Sedan, the spectacle of a ruined and discredited thing. His name and personal characteristics are War Minister skulking about in the twilight under the well known to all who are interested in science, and his shade of the chestnuts in the Poppelsdorfer Allée in position in the history of science is assured for all Bonn in just fear of the taunts and insults of the untime. Whilst his correspondence with Mohr adds but fortunate soldiery whom he had betrayed. little to our knowledge of him as a man, it throws In 1829 Mohr went to Heidelberg, where he came in many sidelights on incidents which occurred during

contact with Leopold Gmelin. He had already the most interesting and active periods of his acquired a considerable knowledge of operative career. Thus, for example, we learn for the first time chemistry and of pharmacology under his father's of the relative share of Liebig and Wöhler in the work tuition. In those far-off days the laboratory of an which resulted in the classical memoir on bitter almond apothecary was a reality, and those who practised the oil Most of the experimental work was due to calling were not merely chemists by prescription, but Wohler; the interpretation of the facts and the com- were such in fact. They were for the most part well pilation of the memoir was made by Liebig. It would skilled in chemical processes, and actually made the appear, in fact, that Wöhler never saw the memoir greater number of the substances in which they dealt. until the proof of it was sent to him.

The influence of this early training is to be seen in Indeed, the chief interest of the correspondence, so the character and scope of Mohr's subsequent work. far as it relates to Liebig, is concerned with his work | He was essentially a practical chemist, and his as editor of the famous periodical-the Annalen der services to the science consisted mainly in the improveChemie und Pharmacie-which is now permanently ments he effected in operative chemistry. Many of associated with his name.

these humble but useful inventions were not calculated The name of Friedrich Mohr is much less familiar, to bring their author much fame, but if his connection at all events to the chemists of this generation; and with them is well-nigh forgotten they at least secured yet the author of the “ Titrier-methode "—the practical for him the gratitude of his contemporaries. How founder of the art of volumetric analysis-deserves to many of the present generation of workers, it may be be had in remembrance. He was a representative of asked, associate his name with that commonest of a type of man of which few examples, at least in this laboratory appliances—the cork-borer? country, are left to-day, viz. that of the scientific Mohr remained at Heidelberg two years, and then apothecary. He was by instinct, training, and practice repaired to Berlin to listen to Heinrich Rose's lectures. a man of science, and he brought his knowledge, ex- | In 1832 he returned to Heidelberg and took his degree perience, and aptitudes as a man of science to the -summa cum laude. What a summa cum laude exercise of his calling. In this respect he resembled meant in 1832, so far as regards chemistry, may be many of those who laid the foundations of modern inferred from the fact that the “hoch berühmten chemical science. In the early part of the last century | Führer,” Gmelin, recorded that “the Herr Kandidat the occupation of the apothecary was practically the answered his questions on the chemical relations of only one open to the man who had his living to make, iodine, the preparation of potassium iodide, the disand who at the same time wished to exercise his passion covery of arsenic and on the preparation and comfor chemical inquiry. Teaching appointments were position of ether to his complete satisfaction.” few, and even where chemistry was taught the Creuzer found that he displayed considerable knowopportunities for experimental work were very meagre. ledge of what the old Greeks and Romans knew of

Mohr was born in Coblenz at about the time that botany and materia medica, and that he had a comDalton gave the New Philosophy to the world. His petent acquaintance with their languages; Muncke father, Karl Mohr, apothecary, town councillor and was satisfied with his answers concerning the balance, the pyrometer, and the electrical relations of bodies; the scattered observations on ornithophilous pollinLeonhard with those on mineralogy and geology; and ation it renders possible a survey of existing knowSchweins recorded that the “ Kandidat als Pharmazeut ledge concerning the inter-relations of birds and ungewöhnliche Kenntnisse in der Mathematik besitzt ” flowers. · Yet the facts recorded show the rudimentary -whatever that might imply.

stage of our knowledge as to the significance of birds The subjects in which Mohr took his degree con

in the shaping of flowers. Scattered through the pretinued to interest him to the end of his days. In sent work we find evidence of actual or possible ornichemistry he was no theorist; indeed, the speculative thophilous flowers belonging to a considerable number side of this science seemed to have little or no attrac

of natural orders, including the Bromeliaceæ, Liliaceae tions for him; and this is the more remarkable when | (Alöe), Scitamineæ, Orchidaceæ, Proteaceæ, Lorit is remembered that in other departments of human anthaceæ, Ranunculaceæ (Aquilegia), Capparidaceæ, thought he let his imagination have the fullest play, Rosaceæ (almond, peach, quince), Caricaceæ, Leguas may be seen in his “ History of the Earth.” minosæ, Melianthaceæ, Balsaminaceæ (Impatiens), Further, Mohr has some claim to be regarded as an Malvaceæ, Cactaceæ, Rhizophoraceæ, Myrtaceæ, independent discoverer of the law of the conservation Marcgraviaceæ, and Passifloraceæ. Included among of energy, as his tombstone in the old “ Friedhof” these are flowers, such as the peach and almond, in Bonn testifies.

obviously not originally ornithophilous, and others, To the historian of chemistry these letters have a such as Passifloraceæ and Aquilegia canadensis, the special interest. If, as has been said, they add little pollination of which by birds is dubious. Still others to our knowledge of Liebig as a man and as a leader there are, such as Carica Papaya, the structure and in science, they nevertheless afford much valuable in- creamy tint of the flowers of which scarcely suggest formation concerning matters which agitated the ornithophily. Other observations show that in chemical world during some of the most stirring periods different parts of the earth the same species of flower of the last century. They have been most carefully is visited by different animals. For example, the annotated by the editor and his assistants, as the entomophilous Japanese Eriobotrya japonica is visited numerous foot-notes indicate. Many passages and by humming-birds in South America, and by honeyallusions which might have been obscure have been birds in South Africa. On the other hand, certain elucidated by their patient research. We can heartily natural orders, such as the Loranthaceæ and Mimoscommend the book to all who are interested in the

aceæ, markedly show pollination, or at least regular personal and biographical history of chemistry.

visitation, by honey-birds in the Old World and by T. E. T.

humming-birds in the New World; and some flowers

of remarkable structure, such as those of Amherstia THE BIONOMICS OF EXOTIC FLOWERS.

nobilis and Hibiscus schizopetalus, visited by birds Handbuch der Blütenbiologie. Begründet von Dr.

seem to demand correspondingly remarkable methods

of pollination. Paul Knuth. iii. Band. Die bisher in ausser

The fragmentary nature of our knowledge in regard europäischen Gebieten gemachten

gemachten blüten-biologischen Beobachtungen unter Mitwirkung von formation in regard to some of the commonest plants.

to pollination is shown by the lack of published inDr. Otto Appel. Bearbeitet und herausgegeben von For instance, Bombax malabaricum is not mentioned Dr. Ernst Loew. i. Theil. Cycadaceæ bis Cornaceæ. Pp. 570; mit 141 Abbildungen im Text. common in some regions; and in southern China I

in this work, yet it is very widely distributed, and even (Leipzig: Engelmann, 1904.) Price 175. net.

know that its large red flowers are visited by small THIS HIS valuable summary of available information birds. In some cases the omission of information is

concerning the pollination of exotic flowers main- due to oversight on the part of the authors; for tains the high standard of the preceding volumes, example, there is no reference to the Vallisneria-like though it naturally deals with knowledge essentially pollination of the submarine Enhalus. The work also fragmentary and only rarely founded on a statistical shows that additional observations are required in rebasis. The work does not limit itself to imparting gard to some of the commonest tropical plants. As a information upon actual observations on pollination, case in point, it may be said that few of those who have but in some cases includes accounts of the forms and scented Pandanus odoratissimus at distances of a colours of flowers, the arrangement of their nectaries, quarter of a mile will accept without further examinand even the microscopical details of fertilisation. As ation the view that littoral species of Pandanus are examples of the various matters dealt with, the follow- anemophilous. Or, again, Knuth found that the ing may be cited :-Freycinetia and its suggested flowers Cassytha filiformis were mostly cleistogamous pollination by bats, the remarkable synchronous on the coral islands of the Java Sea; but unpublished blossoming habits of Dendrobium crumenatum, observations of my own on Dane's Island, near Canton parthenogenesis in Ficus, Kooders's work on tropical (China), sufficiently showed that this is not the case geocarpous plants, the fertilisation of Rhopalocnemis, everywhere. the peculiar flowers of the commelinaceous Cochlio In regard to the printing of the work, it must be con stema and their morphology, species of Yucca and fessed that misprints are too numerous, a brief examintheir relations with Pronuba.

ation showing the following :-Kleistoam, MagroAmong the many interesting features of the work glossa, Abitulon, Spahtiphyllum, and Bromeliwe may note that in bringing together in one work aceenhlüten.

Percy GROOM.


RECENT PHILOSOPHICAL WORKS. would perhaps be well if the author's name and the (1) 4 Primer of Philosophy. By A. S. Rappoport,

title of the work in question were added in every case. Ph.D. Pp. 118. (London: John Murray, 1904.)

(4) The first volume of “ Der Skeptizismus in der Price is. net.

Philosophie " contains account only of Greek 12) Religion und Naturwissenschaft. Eine Antwort | scepticism, that is to say, of Pyrrhonism and of the

an Professor Ladenburg. By Arthur Titius. Pp. scepticism of the Later Academy. But as many of the 114. (Tübingen und Leipzig : J. C. B. Mohr (Paul chief problems raised by scepticism in all ages are disSiebeck), 1904.) Price 1.80 marks.

cussed here at considerable length, this first volume (3) Philosophische Propädeutik auf Naturwissenschaft-cannot safely be neglected even by those who are chiefly

licher Grundlage. By August Schulte-Tigges. interested in Hume, the partial” scepticism of Kant, Zweite verbesserte und vermehrte Auflage. Pp. or modern positivism. The author shows himself a

svi + 221. (Berlin : Georg Reimer.) Price 3 marks. most competent guide. He is always fair minded; even 6) Der Skepticismus in der Philosophie. By Raoul where it is most difficult to be patient with certain well

Richter. Erster Band. Pp. xxiv+ 364. (Leipzig : known quibbles of the Pyrrhonists he labours seriously Dürr'sche Buchhandlung, 1904.) Price 6 marks.

to discover the grain of truth amid the heap of chaff.

Almost a hundred pages are given to a discussion of 11) R. RAPPOPORT'S book, which appears in DR;

“sensual scepticism," i.e. the scepticism which bases Mr. Murray's new series of primers, is on the u hole a very satisfactory introduction to the study of object experienced by different living creatures, by

itself upon the contradictory perceptions of the same philosophy. The statement is always accurate, interest- different human beings, by the same human being ing and suggestive, and the terminology is carefully

at different times, and the like. These arguments, chosen. There are many interesting quotations; according to this work, have weight only as against perhaps those from the German will not always be extreme realists, and both (extreme) idealism and understood without a translation by the average moderate realism (e.g. the realism of Locke) are rereader of a primer. On p. 2 the statement “it was

presented as able to face the situation. With which astonishment that first made man philosophize” is of the two last named the author's sympathies ultiattributed to Aristotle. No doubt Aristotle said so, | mately lie is not apparent from this first instalment; but Plato had the same idea before him. On p. 45 the it will doubtless become evident in the second (and term sociology is said to be derived from the Latin concluding) volume. It is to be hoped for every reason word socius, society (sic).

that so excellent a work will soon reach completion. (2) “ Religion und Naturwissenschaft " is a counterblast to a lecture given by Prof. Ladenburg of Breslau,

THE CHRISTIAN CENTURY IN JAPAN. on the influence of the natural sciences on the

Geschichte des Christentums in Japan. Weltanschauung. Prof. Ladenburg, as represented

By Dr. J.

Haas. Band ii. Pp. xxvii +383. (Tokio : 1904.) by the quotations from his work, appears to believe that experiment, observation, induction, are the key IN this second volume Dr. Haas-whom we conof all knowledge, and that all the progress of the last

gratulate on the well merited doctorate in theology centuries has been caused chiefly by the enlightenment recently conferred upon him by the University of due to the natural sciences. This rather extreme posi- missions in Japan from the departure of Xavier in 1549

Strassburg-pursues the history of the Christian tion Prof. Titius assails with some success, and then proceeds to vindicate the spiritual life of man,

to the year 1570 under the leadership of the Jesuit individualisation, Wertbestimmung, Christianity, even superior Cosmo de Torres, of Valencia. During that miracles, on lines that are not altogether novel. But period, and, indeed, almost up to the close of the the author is no obscurantist, and the argument is

sixteenth century, the task of conversion lay entirely probably as convincing as any popular discussion can

in the hands of the Jesuits, while the increasing trade make it.

with Japan was monopolised by the Portuguese. The (3) The third work on our list is intended to introduce

sources of Dr. Haas's history are almost wholly pupils of the highest classes in Realgymnasien to the European, and above all the famous letters of the Jesuit philosophic principles that underlie scientific method

inissionaries from Japan, of which the volume is largely and the general scientific thought of our time.

The a précis.

These authorities are not, however, first part deals with Methodenlehre, and discusses sufficient, and with the progress of the work it becomes observation and experiment, induction, causal law and more and more evident that the true history of the hypothesis, deduction. In the second part, entitled

Christian century in Japan can only be written in the ** The Mechanical View of the Universe, and the Peninsula, where, as Father Cros's great book on Limits of Knowledge,” there is an adequate account

· St. François de Xavier " tells us, in the inexhaustible of such things as atomism, teleology, the Darwinian archives and libraries of Lisbon and Madrid, and in theory, and the relations of psychical events and their those of Simancas, Coimbra, Evora, and Ajuda, are to physiological accompaniments. On this last head be found the original documents in vast numbers from the author declares himself for a theory of parallelism, which alone an adequate account of that most interestnot as being the solution of the problem, but the ing chapter in the world's history can be gathered. problem itself. The book is excellent both in form and In the score of years covered by the present volume statrment, and all the arguments both for and against the faith was preached over the whole of Kiushiu and

particular view are most fully and impartially stated. most of Central Japan, the northern and eastern Thr quotations show a wide range of reading; but it Daimiates and the whole of the great island of Shikoku being untouched. This work was accomplished by In some three hundred pages Dr. Hutchison deeleven Jesuit fathers, assisted by four converts. In scribes aspects of some of the more common diseases 1564 the Daimio of Omura, the first Christian Daimio, of childhood which, as he says, " are not usually dealt

with in systematic lectures.' In the first instance, known as Sumitada, or Omura Risen (Risen was his

the lectures were given at the London Hospital; subBuddhist name), was baptised, and adhered to the sequently they were published serially in the Clinical faith until his death in 1587. It is of this convert that Journal, while their present appearance in book form Crasset writes :

is in response to the request of a number of readers who

wanted them in a convenient form for reference. “ He went to the chase of the bonzes as to that of

The early chapters deal with the problems of infant wild beasts, and made it his singular pleasure to

feeding, and the subject, which unfortunately is closely exterminate them from his states (“Murdoch,”

allied, of the various digestive disturbances which occur P. 238).

in hand-fed babies. Upon questions of diet Dr. It would, however, be merely special pleading to take Hutchison speaks with special authority, and his rethis language literally, otherwise than as expressing marks on the difficult subject of artificial feeding are

concise and practical. the worthy father's admiration of the vigour with which

In the space of a short lecture it is not possible or the newly made convert promulgated Christianity desirable to deal with all the conceivable methods by within his petty domain. Up to 1570, out of the fifteen which children might be, or have been, fed, but it · or sixteen millions of Japanese, some twenty thousand seems an omission not to mention “ laboratory” milk, had been baptised. This seems a small proportion, which, whatever its objections, certainly offers the

physician a method of wonderful precision in prebut the true measure would be the ratio of the baptised scribing the exact percentage of fat, proteid, and lactose to the population of those parts of Japan where the

which he requires for any individual patient. The gospel had been, with some adequacy, preached. As establishment in London of the Walker Gordon to the quality of their Christianity it is difficult to form Laboratory, at which this milk can be obtained, and

the existence of a farm in connection with it at which a judgment. The steadfastness of large numbers

every precaution is taken to procure germ-free milk under persecution is some guarantee of the reality of

with scientific accuracy, certainly deserve mention in their belief; on the other hand many in becoming any book which deals with the subject of substitute Christians followed the example or obeyed the com- | feeding. The expense of " laboratory milk puts it mands of their feudal superiors.

beyond the reach of many babies, but it is less expensive Another much debated point, not easy to determine,

than a wet nurse, and avoids all the disadvantages

inseparable from employing one. is to what extent the native converts provoked ” the immense majority who still adhered to the Way of the various common diseases of childhood.

In succeeding chapters Dr. Hutchison deals with

They are all Gods and the Way of Buddha. It is certain that the delightful reading, full of common sense and helpful Buddhists were provoked," but there is little evidence suggestion as to diagnosis and treatment. One would that they had any real cause of complaint during the like to quote extensively, but the book is one that

every student of the subject, whether he be qualified period now considered—the provocation was of a

or not, should possess. passive, not of an aggressive character. On the

Special interest attaches to the lecture on mental whole, the fathers were far from unpopular with the deficiency in childhood, often a subject of great difficommon folk. They were looked upon as superior culty in practice, and one with which the ordinary textbeings, and froez says of his reception at Yoko- book scarcely deals. The photographs illustrating this

chapter are particularly good. seura :

The concluding chapters are devoted to the diagnostic “ All the Christian inhabitants came to meet us and significance of some common symptoms, such as

so delighted at our arrival that they would wasting, cough, fever, &c. It is impossible to do full willingly have taken us on their shoulders and borne | justice to this delightful book in a short notice. The us off."

work forms a valuable adjunct to the good text-books

already written on the subject, and it shows to the full It was not until 1587 that persecution began, the

the clinical knowledge and the literary ability of the result of a fit of policy of the cruel, crafty, but capable author, whose reputation, already high, will no doubt Taiko, Hideyoshi.

be increased by it. Dr. Haas writes lucidly, and his pages are full of Elementary Manual for the Chemical Laboratory. By interesting details; but the narrative is obscured by Louis Warner Riggs, Ph.D., Instructor in Chemistry an over-abundance of matter that might well be rele- in Cornell University. Pp. vi+138. (New York: gated to notes or appendices. The Germans seem

John Wiley and Sons; London : Chapman and Hall, unable to distinguish between books and note-books.

Ltd., 1904.) Price 5s. 6d. net.
F. Victor Dickins.

This volume embodies the author's idea of what should
be taught during a one-year course of chemistry, the

time available being not less than a hundred and OUR BOOK SHELF.

twenty hours for laboratory practice, and sixty for

“ recitation " work. It is arranged in short numbered Lectures on the Diseases of Children. By Robert paragraphs, each containing a direction to the student Hutchison, M.D., F.R.C.P. (London : Edward

or an explanation of some point or process, and is inArnold.) Price 8s. 60, net.

tended to be used, under the guidance of an instructor, Ir is difficult to praise this little volume too highly. It in conjunction with general text-book of deals with one of the most attractive and satisfactory chemistry and physics. subjects in medicine, the treatment of children's dis- About one-third of the work is devoted to preeases; the style is excellent, and the illustrations, liminary experiments in general chemistry. The which, with one or two exceptions, are taken from student is then introduced to simple volumetric photographs of the author's cases, are unusually good. I analysis, the principles of which are very well explained



--this forming, perhaps, the best portion of the book. having been increased from fifty-five to sixty-eight. After three experiments in gravimetric work the learner It may be considered as forming a most excellent guide passes on to systematic qualitative analysis, treated to the practice of photography, and a perfect reference from the standpoint of electrolytic dissociation. The for those who so continually question one as to “ the author recognises that, “ logically," the quantitative | best book on photography, for a beginner, you know "; work should follow rather than precede the qualitative; and it will doubtless prove useful as a reference book but after repeated trials he prefers the order indicated. to many who have long passed the beginner stage. In the present connection, however, the matter is more There is a decision of tone and clearness of exposition, one of convenience than of logic.

combined with an intelligent anticipation of the many Accepting the author's system, the experiments questions which arise at every step of the path, which themselves are judiciously selected, and well fitted for render it especially suitable for this purpose. their purpose. But there are educationists who would At the same time, the scientific reader who hopes by no means agree that "theoretical explanations to gain from it some account of the work which has should be reserved for the recitation-room," and not been done of late years, with a view to the clearing given in the laboratory. Still less would they say that up in some measure of the chemical and physical the students should study thoroughly all the details problems in which photography abounds, will probably of an experiment before attempting to perform it," and be greatly disappointed. The two most noteworthy that “this should be done outside the laboratory. features of this, as of almost all English works on Whether such a system would tend to produce a hod-photographic science, are found in the method in which man or an architect would depend, as it seems to the contemporary German literature is ignored, and in writer, less upon its own merits than upon the which the whole of modern physical chemistry is dispersonality of the instructor.

C. S. regarded. The fact, for instance, that development

may be regarded as a reversible heterogeneous reDie Einheit der Naturkrafte in der Thermodynamik. action occurring between ionised salts, in accordance

By Richard Wegner. Pp. viii + 132. (Leipzig : with the mass law, seems to be entirely beyond the idea Von Veit and Co., 1904.)

of this or any other book on the subject. Development As described in the secondary title, this pamphlet is with ferrous oxalate is here represented by the an attempt to deduce from the kinetic energy of non

equation : elastic atoms, corporeal and ethereal, all known 3Ag Br + 3FeC,0,=FeBr, + Fe,(C,0,)+34g, physical forces, chemical, electrical, and mechanical, which, involving as it does the existence of ferric ions only the kinetic energy of moving atoms of different in the developer after use, gives a sufficiently distorted

view of the reaction. While we find the chemical sizes. It is not easy to follow an argument which theory of the book to be of this type, the information provisionally assumes that the atoms are held together to form molecules with regular vibration frequencies no mention whatever being made of the notable re

as to the progress of sensitometry is of the slightest, capable of propagating through the surrounding swarm

searches by Dr. Eder. A most original suggestion as of ether-atoms waves of condensation and rarefaction, by means of the reactions and interference of which found at the close of the chapter devoted to that sub

to the nature of the developable condition is to be (when there are two or more molecules) attractions ject. In brief, this book is a most delightful manual are brought into being; and which then, in terms of this general outlook, gives reasons why the reaction

of the practice of photography, but can scarcely claim

to represent the scientific side of the subject in any of the ether atoms may be found sufficient to hold the

sense whatever.

C. E. KENNETH MEES. corporeal atoms together. A necessary consequence of the investigation is that gravity is propagated in Ants and Some Other Insects. An Inquiry into the time, and should be a function of the temperature. Psychic Powers of these Animals. With an AppenThe author has tested the latter point by experiment, dix on the Peculiarities of their Olfactory Sense. and finds some evidence in favour of its truth. The By Dr. August Forel. Translated from the German source of the chemical elements is found in the different by Prof. William Morton Wheeler. Pp. 49; figures. magnitudes of the atoms, with the corresponding (Chicago, 1904.) Price 2s. 6d. differences in their energetic combinations. The An elaborate treatise on the senses of insects, especially temperature of a body is proportional to the mean ants, illustrated by numerous experiments. The book molecular weight, multiplied by the square of the mean deserves the most serious attention of students of translational velocity of the molecule; divided by the psychology and animal intelligence; but it would relative number of molecules in unit volume; multiplied occupy too much space, nor would any useful object of the relative mean path of the molecule. Since, be gained, by attempting to epitomise either the body according to the theory elaborated, the kinetic energy of the work or even the author's deductions.

We may, of the elementary particles implies attraction, all bodies however, quote the following conclusions :will be surrounded by a layer of condensed gas and “Even to-day I am compelled to uphold the seventh ether particles. In the waves in the ether sheath is thesis which I established in 1877 in my habilitation as found the source of the electrical current. Electro- privat-docent in the University of Munich : static action, on the other hand, depends on chemical ". All the properties of the human mind may be actions in the ether sheath. The applications to derived from the properties of the animal mind.' chemical and electrical phenomena are admittedly “I would merely add to this : Tude and imperfectly worked out; but the author " And all the mental attributes of higher animals claims to have proved the possibility of deducing all may be derived from those of lower animals. In other the recognised forces of nature from the kinetic energy words, the doctrine of evolution is quite as valid in of non-elastic Lucretian atoms.

the province of psychology as it is in all the other The Science and Practice of Photography. By Chap- differences presented by animal organisms and the con

provinces of organic life. Notwithstanding all the man Jones, F.I.C., &c. Fourth edition. Pp. 369. ditions of their existence, the psychic functions of the (London : Iliffe and Co., Ltd., 1904.) Price 55. net. nerve-elements seem nevertheless everywhere to be in This volume, which is the fourth edition of the work, accord with certain fundamental laws, even in the has been very greatly enlarged and rewritten since the cases where this would be least expected on account of appearance of the third edition, the number of chapters the magnitude of the differences."

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