DEPARTMENT OF SCIENCE AND ART. ROYAL COLLEGE OF SCIENCE

FOR IRELAND.

The next Session will Commence on OCTOBER 6.

The Diploma of Associate is given in the Faculties of I. Manufactures (Chemical); II. Engineering; III. Mining; IV. Applied Physics (for Electrical Engineers, &c.); and V. Natural Science.

Two Royal Scholarships of £50 per annum, with Free Admission to the Courses, are competed for each year, by first-year Students.

The Courses of Chemistry, Physics, Botany, Zoology, Geology, and Mineralogy qualify for the Examinations at the R.U.I. and elsewhere; Certificates are granted to Medical and other Students attending the Courses and Laboratories.

Special Courses to suit individual Students, and Research Work in all subjects.

Chemical, Physical, Botanical, Zoological, Geological, and Mineralogical Laboratories, open for Practical Work.

ROYAL COLLEGE OF SCIENCE,

LONDON

(WITH WHICH IS INCORPORATED THE ROYAL SCHOOL OF MINES).

Dean Prof. J. W. JUDD, C.B., LL.D., F.R.S,
SESSION 1896-97.

The Session opens on Wednesday, October 7, at 10 a.m.
There will be a Distribution of Prizes and Medals, and an Address by the
DEAN, in the Lecture Theatre of the Museum of Science and Art, South
Kensington, at 2.30 p.m.

BALLIOL COLLEGE, CHRIST CHURCH, AND TRINITY COLLEGE, OXFORD.

NATURAL SCIENCE SCHOLARSHIPS AND EXHIBITIONS. A Combined Examination for Natural Science Scholarships and Exhibitions will be held by the above Colleges, beginning on TUESDAY, NOVEMBER 17, 1896.

Three Scholarships and two Exhibitions will be offered, the Scholarships being worth £80 a year.

The subjects for Examination will be Physics, Chemistry, and Biology, but Candidates will not be expected to offer themselves in more than two of these.

Particulars may be obtained by application to
Christ Church, Oxford.

A. VERNON HARCOURT.

SCHOOL OF SCIENCE.

PENYWERN HOUSE, 2 and 4, PENYWERN ROAD,
EARL'S COURT, S.W.

PRINCIPAL-G. W. DE TUNZELMANN, B.Sc., M.I.E.E.
SENIOR-INSTRUCTOR-C. CAPITO, M.I.E.E., M.I.M E.

Laboratories, Dynamo Room, Steam Engine, Engineering Workshop with Machine Tools, Pattern Shop, &c. The College provides a Training for Electrical, Mechanical, Civil, and Mining Engineers, for Science Students in Mathematics, Physics, Chemistry, Biology, Geology, and Mineralogy, and Preliminary Training for Students entering Cooper's Hill and the Central Institution.

LONDON B.Sc. and INTER-SCIENCE

HONOURS BOTANY.-A special Course of Lectures for the above Examinations will begin the First Week in November. Practical and Theoretical Work. For full details, apply R. C. B. KERIN, B.A. Lond., Carlyon College, 55 and 56 Chancery Lane, W.C.

FOR SALE. "NATURE," 1877 to 1889,

Unbound.-S.," Thorndale, Craven Road, Reading.

THE

Just Published, Price 3s., Free by Post, 35. 44d. OWENS COLLEGE CALENDAR

for the SESSION 1896-97.

MACMILLAN & CO., London; J. E. CORNISH, Manchester.

A

THURSDAY, OCTOBER 1, 1896.

CHEMISTRY IN DAILY LIFE. Chemistry in Daily Life: Popular Lectures. By Dr. Lassar-Cohn. Translated by M. M. Pattison Muir. Pp. x + 324. (London: Grevel and Co., 1896.) BOOK which professes to instruct the public, uninitiated into technical language or methods, concerning the results of the application of scientific principles to the purposes of daily life, must possess a combination of qualities not easily associated together. It ought to be true-that is, the positive statements it contains ought to be facts, and yet, though its pages should present the truth and nothing but the truth, it is

impossible that it should give the whole truth in regard to many subjects it must pretend to discuss. Here is the grand opportunity for the exercise of judgment on the part of the writer, without which and a large proportion of sympathy with his readers the book will be both unintelligible and uninteresting. There must be— and there are many subjects which, from their nature, are incommunicable to the mind not already prepared with a knowledge of fundamental ideas and some familiarity with the technical language or symbols by which these ideas are expressed. Such subjects as many

divisions of pure mathematics and, we will venture to add, of modern chemistry belong to this category.

However, acting upon the view that the best test of the suitability of such a book for the general reader is not merely the opinion of the chemical expert on the subject-matter and the degree of accuracy of the notions introduced, the writer of this notice has placed this little volume in the hands of an educated but not technically instructed friend, with a request to read it carefully, appealing for help or explanation if necessary. is the kind of thing that follows :-

This

"Please tell me the meaning of this: 'The green parts of the leaves are called chlorophyll-grains,' also 'silica is the chemical name for pure sand'; and, pray, what is humus?" (pp. 38-40).

A little later the reader says:

"Listen: "A cannon exhibited by Krupp at the Chicago Exhibition, when charged with 115 kilos of this powder, propelled a shot weighing 215 kilos to a distance of 20,226 metres; the flight of the shot occupied 70 seconds, and the highest point attained was 6540 metres above the earth, while the height of Chimborazo is only 6421 metres.' What does all that mean, and what has the highest point got to do with it?"

These are sufficient examples of the, perhaps, not very serious difficulties encountered by the general reader, who at the end remarked, “Oh, yes; I found it interesting."

Now let the chemist take a look at the volume. As already hinted, the impossibility of stating some things without resort to technical language leads to a great deal of extremely loose and objectionable phraseology Take the following passage (p. 46) for example :--

"Most of the phosphoric acid in the materials we have mentioned is combined with lime in the proportion of three molecules of lime to one molecule of the acid. Sulphuric acid is a stronger acid than phosphoric; but one molecule of sulphuric acid combines with only one

Here we have a series of statements all more or less embodied in the scheme, which asserts that sulphuric open to criticism, the culminating misrepresentation being anything in the place of it. This, however, is just the acid withdraws lime from the phosphate without leaving kind of thing which it is well-nigh impossible to express correctly in popular language. The worst of it is that the same erroneous idea crops up in so many other places. The worst case we have encountered occurs on p. 51, where ammonia is said to be an alkali or a base, for few lines further on it is announced that “bases and acids these names have to-day the same meaning." And a is a basic gas, carbonic acid is an acid gas, sulphuric gases, liquids, or solids. Ammonia, for instance, acid is a liquid, and silicic acid is a solid." After such a descent towards the popular level, it is difficult to believe that anything can be gained by the introduction of chemical formulæ, especially such as occupy the last ten pages, where an attempt is made to explain the constitution of alkaloids and other complex carbon compounds.

may be

All this kind of thing was managed much more successfully in "The New Chemistry" of the late Prof. Josiah P. Cooke, which, though published twenty years ago, is still trustworthy and, in point of literary quality, incomparably superior to such a jumble of information not always to be depended upon for accuracy, and sometimes descending to the almost ludicrous. One cannot but wonder whether the author was serious or cynical when he wrote that phosphoric pig-iron "is only fitted for making the coarsest sorts of cast-iron ware, such as railings for graves and the like, in which no great durability is looked for." The italics are ours.

The author does not often exhibit emotion, but bimetallism is too much for him, and he lets his pen run. The whole story is too long to quote, but one passage affords such a remarkable example of style, unspoiled by a conscientious translator, that it is worth reproducing.

"There is one thing which the bimetallists would certainly achieve, as long as they do not get rid of the fluctuations in the price of silver, were they to induce the civilised States to inaugurate an international bimetallism in that Utopia which they depict to any one who will hearken to them as the approaching economical rejuvenescence of the nations for none of them has assertions because no such argument exists, for if there brought forward a decisive argument in favour of their were such an argument it would certainly be easy to induce the most influential nations to adopt bimetallism again-and this one thing which they would undoubtedly do would be to enable the proprietors of American and Australian silver mines, one of whom is already the richest man in the world, to make yet much greater

profits from their mines, in which profits Europeans have as yet no great interests," &c.

After this it is not surprising, as the translator informs us in the preface, that the publication of the book "caused quite a stir in German circles."

OUR BOOK SHELF.

Crystallography for Beginners, with an Appendix on the use of the Blowpipe and the Determination of Common Minerals (after the method of Dr. Albin Weisbach). By C. J. Woodward, B.Sc. Pp. 164. (London: Simpkin, Marshall, Hamilton, Kent and Co., Ltd., 1896.)

IN a preliminary chapter of this book the student is taught how to prepare for himself, with due regard to economy of purse, a set of models to be used in connection with the various lessons. In the course of the

following 72 pages the constancy of the angles of crystals, symmetry, notation, drawing of crystal forms and spherical projection, are in turn explained. The physical properties of crystals are then briefly touched upon, and in a last lesson mero-symmetry is discussed. The appendix (55 pages) deals with a subject entirely different from Crystallography, namely Determinative Mineralogy, and is made up almost wholly of tables drawn up after the manner of those of Dr. Weisbach. The book contains numerous woodcuts in the text, and is furnished with four plates, two of them consisting of diagrams to be pasted on cardboard and used in the construction of the aforementioned models. To each lesson is appended a set of useful questions relating to the subject which has been discussed. Some of the statements are wanting in accuracy for instance, on page 55 the student is told that "the symbols of all planes in a zone have two of their indices always in a constant ratio," which is untrue; and at times the language is wanting in neatness and precision: still, if the student is in the hands of a careful teacher, he will be able to get much help from the book, and is not likely to be led astray.

By the Deep Sea; a Popular Introduction to the Wild Life of the British Shores. By Edward Step. Pp. 322. (London: Jarrold, 1896.)

THE author of this little volume is already favourably known by his popular books on wild flowers, &c., and the present work will add to his reputation as a writer for the non-scientific reader. The author's endeavour has been to introduce to the seaside visitor a large number of the interesting creatures to be found on the rocks, the sands and the shingle, and he claims to have written the whole of the work in close contact with the objects he describes-not only of cabinet specimens, but of the living creatures under natural conditions. In his own words: "There is not a line in the whole volume that has not been written within a few yards of, and in full view of the rocks." The twenty chapters into which the book is divided are devoted to the sea and its shores, low forms of life, sponges, zoophytes, jelly-fishes, sea-anemones, seastars and sea-urchins, sea-worms, crabs and lobsters, shrimps and prawns, some minor crustaceans, barnacles and acorn-shells, "shell-fish," sea-snails and sea-slugs, cuttles, sea-squirts, shore fishes, birds of the seashore, seaweeds, flowers of the shore and cliffs. The style of writing is easy and attractive, and the text is further elucidated by the insertion of a number of well-chosen, if somewhat rough, illustrations from the works of P. H. Gosse, and others which appear to have been specially drawn for the work. Many a seaside holiday will be more fully and permanently enjoyed by the study of this tastefully got up little book, the usefulness of which is increased by a general and a classified index.

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.]

The Utility of Specific Characters.

I HOPED that I might have held my peace on this subject. Prof. Lankester, however, complains, and not for the first time, that I have misrepresented, or at any rate misunderstood him. though he has allowed a long time to elapse before criticising it. I do not doubt his acquaintance with Prof. Weldon's work, I am glad that he regards it as "interesting and valuable." But this is what he said about it in But this is what he said about it in NATURE for July 16 last :"Such methods of attempting to penetrate the obscurity which veils the interactions of the immensely complex bundle of phenomena which we call a crab and its environment, appear to me not merely inadequate, but in so far as they involve perversion of the meaning of accepted terms and a deliberate rejection of the method of inquiry by hypothesis and verification, injurious to the progress of knowledge."

But it

It is quite true that Prof. Lankester has not said in so many words that "Prof. Weldon's investigation of the crab's carapace does not satisfy the canons of scientific inquiry.' appears to me that this is a very mild way of putting what he did say.

I expressed the opinion that Prof. Weldon's investigation did rest on an hypothesis, and that this was subjected to verification. Whether the hypothesis was reasonable and the verification adequate is a matter on which Prof. Karl Pearson and others are entitled to form their own judgment. Kew, September 28. W. T. THISELTON-DYER.

I FEEL grateful to Prof. Karl Pearson for his lucid and rational contribution to this discussion, in which it has sometimes seemed to me that the main question was in danger of being obscured by more or less irrelevant arguments.

I pointed out in a letter to NATURE, soon after the publication of Prof. Weldon's report last year, that he had not, and had not claimed to have, proved that there was a differential or selective death-rate in shore crabs, with respect to variations of their frontal breadth. He showed that the curve of variation in larger (and therefore presumably older) crabs was different from that in smaller crabs. The departures from the mean were less. He concluded, that if this difference were not due to growth-changes

it must be due to the death of crabs with extreme variations. But on the other hand it had to be proved that the difference was not due to growth-changes. Changes in the proportions of parts are so common during growth in so many animals, that it seemed to me much more likely that the difference discovered by Prof. Weldon was due to such changes than to a differential death-rate. I understand that he has since been investigating what he calls the law of growth in these crabs, but so far as I know he has not published any further results.

I am glad to find that Prof. Karl Pearson's opinion concerning the conclusions to be drawn from the evidence published by Prof. Weldon, entirely agrees with mine. It would be very interesting to learn now whether Prof. Weldon is able to settle crabs, and either to confirm or withdraw his suggested conclusion the question of the changes occurring in the growth of shore that the difference he described was due to selective death-rate. It would take a good deal of evidence to convince me that shore crabs in which the frontal breadth differed slightly from the mean, died in greater numbers than those in which it was nearer the mean. But if the evidence is forthcoming, I am ready to accept it. It seems to me that Mr. Thiselton-Dyer is inclined to accept the conclusion before the evidence is forthcoming. He seems to have overlooked the other possible explanation of the result, namely changes in the same crabs during growth.

I also maintained in my letter last year, as Profs. Lankester and Karl Pearson maintain now, that if a differential death-rate were demonstrated, it would still be necessary to discover how that death-rate was caused, what was the relation between the character in question and the conditions of life which caused individuals with certain variations of the character to die off.

I do not profess to be a specialist in logic, but it seems to me that the fallacy into which Prof. Weldon has fallen is that of confounding the categories. He maintains that if a certain

variation is correlated with a certain death-rate, it must be the cause of it, and that it is not possible to distinguish between variations which are directly useful, and those which are only physiologically correlated with the useful. But it seems to me that this is like talking of hitting a nominative case with a stick. The variation is a magnitude in an organism, survival or death is a relation between the organism and its environment. It is the relation of the variation to life which alone can be said to be the cause of death or survival. The relation to the conditions of life is advantage, disadvantage, or neutrality in the struggle for existence. If I have stated the logic of the matter correctly, I venture to think that the apprehension of this principle is a necessary preliminary to any attempt to demonstrate empirically the occurrence of natural selection.

If

Prof. Weldon's chief contention was that by the statistical method, when the law of growth of the characters examined was known, a measure of the rate and direction of the evolution of an organism could be obtained. Such a measure would be afforded by the selective death-rate. But he has not yet demonstrated a selective death-rate in a single instance. And further, a measure of the rate and direction of evolution has nothing to do with the cause of the selective death-rate. characters of no apparent utility are proved to be subject to selection, there still remains the question how the selection is brought about. Measures of the rate and direction of the wind do not tell us the cause of the wind. They may help us to discover the cause, and I have no doubt that Prof. Weldon's investigations are a valuable contribution to the investigation of evolution. But it is only when it has been shown that the degree of utility of a variation, or its correlation with useful variations determines its survival, that the occurrence of natural selection has been demonstrated. J. T. CUNNINGHAM. September 19.

Fossil Tridacnids in the Solomon Islands. SOME months ago, on the voyage between New Guinea and Sydney, the small trading steamer on which I travelled called at a number of islands in the British Solomons, the first station at which we called being Rubiana, in the little-known islandcomplex of New Georgia. Here I became acquainted with the heavy arm-rings worn by the natives, and obviously made from the shell of Tridacna or Hippopus. What was very surprising, however, was the information which I obtained from all quarters and from different localities, from blacks as well as from whites, that these arm-rings are not made from recent shells found on the reef, but from shells obtained far away in the interior, or, as they say, in the bush. At first sight, the arm-rings, above referred to, strongly remind one of those made from the recent Tridacna by the natives of the Sir Charles Hardy Island, which lies to the north of the Solomon Group; but while the former are solid rings more than half an inch in thickness, the latter are deeply grooved on the outer border.

This difference is shown in Figs. 1 and 2, which represent cross-sections through the arm-rings of the Solomon and Sir

Charles Hardy islanders, respectively. But there are other differences, not so much of artistic as of economic importance. The grooved rings are much more readily obtained from the natives who make and wear them, than are the solid rings. The latter have a great value among the natives themselves, and when they are shot with a vein of reddish or reddish-yellow colour (derived no doubt from the hinge-line, which also gives their beauty to the nose-pieces of the New Guinea natives), they can only be mentioned with bated breath.

The reason why the Solomon Islanders prefer the ancient to the recent shells, lies possibly in the fact that, as a general rule, among the natives of the larger islands of the Pacific, the artists and artificers (apart from the making of canoes) are to be

The

found among the bush-natives, rather than among those who live in proximity to the sea. The latter are traders, par excellencemen of the world who do their business in great waters. former live in primitive innocence, are possessed of uncouth manners, and produce poets, magicians, medical men, and professional dancers, together with workers in wood and stone. To the last-mentioned members of the community, therefore, the Tridacnid shells, when they occur in the bush through elevation of a former coral reef, are ready conveniently to hand.

I have thought it worth while to draw the attention of naturalists to the above indication of the existence of upraised coral reefs in the Solomon Islands, which would be well worth an attentive examination, and, while in Sydney, Mr. R. Etheridge, jun., informed me that he knew of other instances in the Pacific of coral reefs having been raised to an elevation of over a thousand feet. ARTHUR WILLEY.

Nouméa, New Caledonia, July 16.

Visual Aid in the Oral Teaching of Deaf Mutes. PROBABLY every one is acquainted with Koenig's manometric capsules and revolving mirrors, and it occurred to me that I might help a deaf mute to learn inflection in speaking by his imitating the curves produced by my voice in the mirrors. For this purpose I arranged two capsules with oblique membranes and small diameter side by side, one being higher than the other, so that two bands of flame half inch wide, and half inch apart, appeared in the revolving mirrors. The capsules were tuned alike, and furnished with tubes and conical mouthpieces; through one of these I made the sound of a note, vowel, or syllable in various pitches, and my friend endeavoured to imitate through the other tube the curve in the flame band produced by my voice. As an experiment the results were quite satisfactory, for before an hour was over he could imitate a range of nearly an octave, and would tell me correctly, through watching the curves of flame, when the note he uttered was like mine. I am not interested in the oral teaching of the deaf, but having frequently to use Koenig's invention, I think the principle might be made useful to oral teachers. My friend, upon whom I experimented, is said to have been well taught, his age about twenty years, but his voice (?) is a hoarse monotone. T. HAWKSLEY. 11 Primrose Hill Road, N. W.

INTERNATIONAL METEOROLOGICAL

CONFERENCE AT PARIS.

HIS Conference was held at the rooms of the Société THI d'Encouragement, in the Rue de Rennes, from September 17 to 23. About forty members were present. M. Mascart was elected President, MM. de Bezold and Tacchini Vice-Presidents, and MM. Angot, Erk, and Scott Secretaries. The complete report of proceedings has not yet been printed. It was decided that Committees should be appointed to continue the investigation of several subjects, viz. :

I. Terrestrial Magnetism and Atmospheric Electricity; Prof. Rücker (President).

II. Clouds; Prof. Hildebrandsson (President).

III. Radiation and Insolation ; M. Violle (President). IV. Aerostatics and Balloon Work; Prof. Hergesell (President).

On the motion of Mr. Symons, the International Meteorological Committee was reappointed with a few changes, rendered necessary by the respective resignations of Prof. Wild, Prof. Harrington, and Mr. Ellery. The President is Prof. Mascart, and the Secretary Mr. R. H. Scott.