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having a special theory of his own. According to According to the generally accepted interpretation the great movement of the ages has been in the direction of increasing complexity and control (differentiation and integration), always allowing for some simplification in the case of parasites and other degenerates. But according to Dr. Marconi's interpretation the historic movement has been in the opposite direction. Mammals did not evolve from a Reptilian stock, but Reptiles from Mammals. Amphibians did not spring from a Piscine stock, but Fishes from Amphibians. The mistake that evolutionists have made in contemplating the stream of life is not a little one; they have actually mistaken the direction of the current! The author asks us to replace the evolution-idea by the involution-idea.

This arch-heresy has been suggested before, but it has never had, so far as we know, such an elaborate and beautifully printed presentation. The author is obviously sincere and in earnest, but le has not learned the humility of refraining from discussing questions, such as cell-division, which he has utterly failed to understand. What are we to say of this ingenuous and occasionally ingenious heretic?

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There was a time long ago when our earth was too hot to offer hospitality to any living creatures of the sort we know about, and it is useless to speak of others. Therefore, so far as the earth is concerned, matter " antedated "life." But it is open to anyone to defend the metaphysical thesis that in the world as a whole "life" is antecedent to "matter." We would not quarrel with Dr. Marconi over a luxury of this sort. But when we remember the fact that according to the rock record there were invertebrates before there were any vertebrates, and fishes before there were any amphibians, and reptiles before there were birds and mammals, and so on, we require arguments more cogent than Dr. Marconi's to persuade us to become "involutionists." And as to the development of the individual, while we agree with the author that the recapitulation doctrine requires careful handling, we do not think that the lifehistory of a frog, for instance, offers any suggestion whatsoever of the reptilian origin of amphibians.

We shall not discuss Dr. Marconi's detailed arguments that cyclostomes sprang from gnathostomes, and ascidians from amphioxus, and echinoderms from enteropneusts, and the branchial arch system of a dogfish from the thoracic skeleton of a mammal, for in truth what he says lacks zoological competence. It would have been profitable if Dr. Marconi had followed Dr. Dohrn and Sir Ray Lankester and restricted himself to

illustrating the occasional occurrence of degenerative or involutionary changes in the history of animal life, but the author will have no halfmeasures. From an originally perfect manifestation of life man has fallen; and the ape and the tiger, the mole and the bat are his descendants!

When we read the words "involution naturelle " on the title-page we hoped that some light would be cast on Prof. Bateson's recent hard saying: "We may as well see whether we are limited to the old view that evolutionary progress is from the simple to the complex, and whether after all it is conceivable that the process was the other way about." But while Dr. Marconi is convinced that it has been the other way about, he starts from a super-man, and we do not suppose that this expresses Prof. Bateson's conception of primordial life. In one of Dostoievsky's novels it is quaintly remarked of one of the characters that he was the only man in the company who could move about on his head. We think that the author of this extraordinary, topsy-turvy interpretation of the world must be similarly unique.

ELECTRICITY FOR THE FARM. Electricity for the Farm. By F. I. Anderson. Pp. xxiii+265. (New York: The Macmillan Co.; London: Macmillan and Co., Ltd., 1915.) Price 5s. 6d. net.

THI

HIS book is addressed particularly to American farmers who may not know how easy it is to make use of a stream of water in producing electric power and transmitting it for lighting and heating and mechanical purposes on a farm. It shows that the initial cost is usually small, that measurement of power is simple, that although the farmer must buy apparatus he can do this without employing an expert, and that he need have no difficulty in putting it up and getting it to work in such a way that it will give no trouble afterwards.

The author knows his farmer well, and his explanations are obviously such as will be understood. How to compute the power required for so many lamps in rooms and out-houses; for so many heaters of various kinds; for so many motors doing small or large domestic or farm work. How to measure the amount of water flowing in a stream, and knowing the fall to calculate the power of the stream. The farmer or his son, who will probably become an an enthusiast, is supposed to have much common sense and a knowledge of simple arithmetic; he will certainly in time get a good working knowledge of electrical engineering. The author makes remarks which may cause a physicist to smile; for ex

ample, "a falling body hits the ground with precisely the same force as is required to lift it to the height from which it falls." He evidently means that the work done in lifting the body is equal to the energy which it will expend in falling. His instructions as to the measurement of water by weirs are too inaccurate to please a water engineer, but they are really accurate enough for the farmer's purpose. His descriptions of turbines are too complex for the farmer and they do not show great knowledge of the subject, but the farmer does not need to understand them. The author is excellent in describing how to make a dam. His description of the dynamo is quite good and easy to follow, and it will certainly interest the farmer in electricity and cause the farmer's son to study the subject more fully, not merely through books, but through simple experiments. On practical matters-types of lamps, sizes of wire, wire joints, Ohm's law, wiring the house and premises, etc.—the author gives good simple instructions. The last quarter of the book is less important; it is intended for farmers who have no water power. It describes gas-engine plant

and accumulators.

The American farmers have a respect for natural science and they are glad to cultivate new ideas. We think that the publication of this book will induce such men and their families to begin a fascinating study at small cost, with results in comfort and a widening of the mental horizon which ought to fill the town dweller with envy.

PRINCIPLES OF STOCK-BREEDING. Breeding of Farm Animals. By Prof. M. W. Harper. Pp. xvii +335. (New York: Orange Judd Co.; London: Kegan Paul and Co., Ltd., 1914.) Price 1.50 dollars.

FEW

EW callings have been more prolific in theories than stock-breeding. Many have been erroneous, while others which have borne a strong semblance of soundness have been inapplicable. Most of them have come from stock-breeders themselves; but others, which, as a rule, have received more attention, have come from outside observers. The great stock-breeders, more especially the great improvers, have given little heed to any other theory than that which has been tersely expressed in the words "put the best to the best," but others have been influenced by other theories, although their success in the production of good stock has usually been parallel with the strength of their adherence to the main theory whether that adherence was conscious or unconscious. After the introduction of printed herd and stud books, and therefore of "pure" breeding, the

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Like many a stock-breeder, Prof. Harper has lost sight of the main theory, and has allowed others to intervene. With him the Darwinian theory has effect as follows: "While the influence of climate and locality is great, and the factors at work are exceedingly complex, yet from a practical point of view we may consider the food supply and more favourable conditions generally, such as sufficient shelter, proper care, including training and developing, as the more important causes of variation." A paragraph is headed "Mendelism a Cause of Variation." And, after three chapters on Improvement due, 1, to "selection based on records of performance,” 2, to “selection the result of prepotency," and, 3, to "accumulative development," it is stated "that the degree of development depends on the environment, including training, management, and the like." Apparently the weight of Bateson's "Materials for the Study of Variation," and Mendel's work has not yet been felt. It is no argument for the Darwinian view to say that "The thoroughbred horse has increased its speed by but eight per cent. in one half a century of racing. During this same period the standardbred, a comparatively new breed, has reduced its trotting record by 27 per cent." The words in italics indicate some part of the argument to the contrary.

Parts of the work of Galton and Pearson are cited, but with no indication how the formulæ of these investigators, even if sound, are to be made use of by stock-breeders; and the idea that "the new individual inherits all the characters of the race to which it belongs," which is cited frequently and appears to be regarded as fundamental, is of very doubtful accuracy when applied to domestic animals. In the chapter headed "Mendel's Law of Heredity," the statements are made that “Mendel made a series of studies . . . from which he drew some general conclusions, now known as Mendel's law of heredity," heredity," and "Mendel's Law . . . depends on three factorsunit characters, dominance, and segregation." Apparently Prof. Harper has become acquainted with Mendel's Law from later writers rather than from Mendel himself.

In his volume, however, a source of information of very great importance is indicated. In the United States, careful records have been kept of the performances of the Holstein-Friesian breed of cattle, and these show that, as they had none, or one, or two parents in what is called the ad

vanced registry, certain sires and dams had different chances of begetting progeny capable of entering the same registry. Surely if these records were closely examined and the failures counted as well as the successes, a more satisfactory theory might be promulgated as to the inheritance of milk and butter yield. The records of trotting horses have also been kept, and the belief is strong that some are the parents of performers while others are the grandparents only: the intervening generation being merely breeders of performers. Surely, again, the failures might be counted and some useful explanation of this phenomenon discovered.

JAMES WILSON.

OUR BOOKSHELF.

The Material Culture and Social Institutions of
the Simpler Peoples: An Essay in Correlation.
By L. T. Hobhouse, G. C. Wheeler, and M.
Ginsberg. Pp. 299. (London: Chapman and
Hall, Ltd., 1915.) Price 2s. 6d. net.

IT is difficult, and may be dangerous, to apply
statistical methods to the sociology of un-
civilised peoples. There are only a few mono-
graphs written on scientific lines; the greater part
of the evidence consists in the incomplete and
often prejudiced accounts of travellers. Results,
therefore, over a wide field, must necessarily be
rough, and, to attain even these, a very skilled
judgment is required. But, for all that, even
rough results of very careful work are valuable.

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The authors of this study in correlation wisely. choose material culture as the general characteristic of civilisation. By reference to this test, they have established advance in organised government accompanying economic development." Similarly, with the social order generally. The chapters dealing with these results are quite masterly, and the authors have the good habit of stating fully their difficulties, and the pros and cons, in the doubtful cases. In various ways it is shown that a purely pastoral society tends to become a "blind alley" of progress. Interesting results follow the discussion of marriage and the family, especially in the cases of polygamy and the "consideration" to the kin.

lines of printed directions at the top, followed in many cases by a ruled form in which the student is intended to enter his results.

The exercises are intended "for high schools, agricultural high schools, and normal schools." There is a list of apparatus required for the exercises, which includes such diverse articles as pietins, tomato-cans, compound microscopes, mill for pulverising soil (why not pestle and mortar?), and a compacting machine for soils, whatever that may be. The exercises themselves include the formation of soils as seen in a road or railway

cutting; experiments on the separation of soil particles, their appearance and properties; the properties of sand, clay, and humus; the behaviour of water and air in the soil; cultivation, implements, fertilisers, and gardening. A teacher who lacked the knowledge or experience requisite for designing exercises himself might find some of the suggested exercises useful, but such a teacher would find himself in trouble with more than one of the exercises. No. 19, for instance, where the scholar is directed to find the percentage of air in the soil by putting a measured volume of soil in a beaker and pouring water on to it until the soil is just covered, would be likely to give very curious results. Again in exercise No. 27, a scholar who was accustomed to working with piedishes and tomato-tins would see all sorts of things except bacteria when "examining with a compound microscope a small sample of fertile soil placed on a slide in a few drops of water."

T. B. W.

The Evolution of the Potter's Art. By T.
Sheppard. Pp. xx. (London: Brown and Sons,
Ltd., n.d.)

THE pretentious title of this publication will disappoint the student in search of an adequate treatdevelopment of a difficult problem. Such a work would not be an easy task for even the most learned ethnographer, because it involves a knowledge of prehistoric and savage culture, acquaintance with the technique of work in clay, and a special familiarity with burial customs. It would be unfair to expect these qualifications in the hardworked curator of a provincial museum. But it is sufficient to quote his comment on the discovery in pots from the so-called Danes' Graves near Driffield of the humeri of pigs: "so that we may assume that a shoulder of pork was food for the gods in the Early Iron Age." He must be aware that the joint was intended as food for the dead man's spirit. The book is really only an edition de luxe of one of the useful penny pamphlets which Mr. Sheppard has issued from time to time for the instruction of unlearned visitors to the

Full tables of all the data used are given, and there is a complete bibliography. The book is absolutely essential to the student of social evolution.

It breaks fresh ground and consolidates new positions.

Agricultural Laboratory Manual: Soils. By Prof.
E. S. Sell. Pp. iv +40. (Boston and London :
Ginn and Co., 1915.) Price 1s. 6d.
THIS is a collection of forty exercises on soils.
The book consists of forty sheets of scribbling
paper held together by paper-fasteners inside a
brown paper cover, so that each sheet may be
used separately by the scholars and then bound
up again with the rest. Each page has a few

museum at Hull. It is fortunate in possessing a good collection of early Staffordshire ware, with examples of the Worcester, Derby, Chelsea, Dresden, and other famous schools. From these materials the "Evolution of the Potter's Art" is worked out in six pages. The best point about the work is the series of sixty-two photographs of the more interesting specimens in the collection.

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 cnonymous communications.]

Colour Sensation.

and questions of this kind can only be settled by the
decision of many eyes, and their decision only applies
to themselves.
JOHN AITKEN.

Ardenlea, Falkirk, August 10.

"The History of Upper Assam, Upper Burmah, and North-Eastern Frontier."

to

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I HAVE had the opportunity of looking through this recent publication, which was reviewed in NATURE, vol. cxiv., p. 481, December 31, 1914. It is most IN NATURE of July 15 there is given an abstract of interesting reading to anyone, but particularly to a paper by Dr. F. W. Edridge-Green in which he those like myself who spent many years on the gives reasons for supposing that the sensation proEastern Frontier among the tribes mentioned. This duced by spectral yellow is a simple sensation, and book covers so large an area, goes back so far into not a compound of red and green, as supposed by the past history of Assam since the East India Comthe Young-Helmholtz theory. In 1872 I read a paper pany were brought into relation with that country, on colour sensation before the Royal Scottish Society and further back into a lost history of its ancient of Arts, in which practically all the experiments greatness, that 256 pages cannot do the subject described by Dr. Edridge-Green are given, but the justice. Very much which has been written of conclusion come to was that spectral yellow gave a Assam, particularly in the Journal of the Asiatic compound sensation, because it could be altered by Society of Bengal and other publications, is not refatiguing the eye with either red or green. ferred I have are at all, while certain parts lately repeated these tests, and find my eyes still give sketchy, even inaccurate. At the same time, very the same reactions. To my eyes, the best yellow much that Colonel Shakespear has written is exis just on the green side of the D lines in the spectremely interesting, and his knowledge and experitrum, but if the eye is fatigued with red light the ence are very considerable, from having served so long yellow is changed to greenish-yellow, and if fatigued in the country, and his conclusions sound. On p. with green it is changed to orange, that is, the 108, treating of events in the Dafla country in 1874, yellow changes in colour towards the unfatigued when Colonel Stafford commanded a force which sensation. Testing by means of a sodium flame entered the country, we find :gives the same result. In making this test, the flame should not be used immediately after lighting it, as it then contains, in addition to the bright yellow lines, a continuous spectrum. The test should be made when the flame is nearly burnt out and the salt crackling. In that condition only the yellow lines are visible, and it shows the change better than in its first condition. To the eye fatigued with red it has a distinct greenish hue, while to the other eye fatigued with green it is reddish. The change is quite marked, and there is no hesitation as to the conclusion.

With regard to the results given in the abstract of Dr. Edridge-Green's paper: (1) Fatiguing the eyes with pure yellow spectral light could hardly be expected to affect the hue of the red, and could only slightly diminish its brightness, which will be difficult to detect. (2) It is difficult or impossible to compare results when the eye in one case is flooded all over with a bright light, and the other in which it is fatigued with a narrow strip of weaker light which cannot be kept on the same part of the retina for any length of time. Results (3) and (4): Dr. Edridge-Green's eyes and mine do not give the same results as stated at the beginning of this letter.

It may be stated that the after-image seen on a white surface after looking at spectral yellow, and by the sodium flame, is the same as that given by a yellow compounded of red and green. Now if spectral yellow gave a simple sensation we would hardly expect this, as the after-image is a compound of all the unfatigued sensations, and we would expect spectral yellow if simple ought to give a nearly white after-image, and not a violet one.

There is an old saying that "Seeing's believing." In ordinary matters this may be so, but the belief is not necessarily true, and in questions of colour full of pitfalls. No two pairs of eyes see colours alike. This does not refer to colour-seeing and colour-blind eyes only, but there is reason to believe that all eyes differ more or less in their perception of colour,

"The Daflas made no resistance, but paid up fines and returned the captives. Little or nothing was done by this large force in exploration or survey, and it returned to Assam amidst a clamour from Government over wasted money" (the words in italics are mine. I would answer this statement by the following extracts from Reports, etc.).

I. The Indian Museum, 1814-1914. Calcutta, 1914. "Bhutan is still an unknown country to naturalists, and its territory represents the most important gap in our geographical knowledge of the Himalayan fauna. East of Bhutan two expeditions of very different date are of zoological importance, namely, the Dafla expedition of 1874-75 and the Abor expedition of 1911-12. On the first of these, Godwin-Austen, then a Major in the Bengal Staff Corps attached to the Survey of India, himself made collections of great value, and also encouraged his subordinate officers to do the like."

II. As to the survey work. In a Memoir on the Indian Surveys, by Clements R. Markham, C.B., F.R.S. India Office Publication. 1878, p. 173.

In 1875 Major Godwin-Austen accompanied the Duffla military expedition against the tribes on the northern frontier of Assam. Narainpur, on the Dikrung Nullah, was reached on December 2, 1874, and from a base on the banks of the Bramaputra a short series of triangles was extended northward into the Duffla hills. Owing to the brief period during which the military were in the country, the survey party were unable to remain beyond two and a half months. The out-turn of work amounted to 1705 square miles of entirely new topography, on the scales of two and four of the season's work in the Duffla hills, has been compiled by Major Godwin-Austen, and is a valuable addition to our geographical knowledge of the region beyond the northern frontier of Assam. Lieut. Harman, R.E., rendered assistance by surveying the course of the Ranga river; and Mr. Lister, of the Royal Botanical Gardens, Calcutta, was assiduous in making a collection of plants, seeds,

and dried botanical specimens. The SurveyorGeneral expresses a hope that these explorations on the Northern Assam frontier will be continued, and is of opinion that with tact and precaution all difficulties in the way of visiting and exploring the narrow strip of hills between the Assam valley and Tibet may be overcome,"

THE

THE GAS INDUSTRY AND EXPLOSIVES. HE need that has arisen for certain coal-tar products for the manufacture by nitration of the high explosives essential in the present war, has riveted attention on the best methods for obtain

As to the natural history work, there was pub-ing these, and of keeping up the supply to the

lished:-

III. Journal Asiatic Society of Bengal, vol. xliv., part ii., 1875: Notes on the Geology of part of the Dafla Hills, Assam; lately visited by the Force under Brigadier-General Stafford, C.B., by Major H. H. Godwin-Austen, F.R.G.S., F.Z.S., etc., Deputy Superintendent Topographical Survey of India, with map. Plate ix.

IV. Journal Asiatic Society of Bengal, vol. xlv., part ii., 1876: On the Helicidæ collected during the Expedition into the the Dafla Hills, Assam, with

plate viii., p. 311. V. On the Cyclostomacea of the Dafla Hills, Assam, p. 171, with plates vii. and viii. a.

VI. List of the Birds collected on the Expedition into the Dafla Hills, Assam, together with those obtained in the adjacent Darrang Terai, with plates iii. and iv., p. 64, by same author. H. H. GODWIN-AUSTEN.

Moustier Implements and Human Bones in Suffolk.

OWING to the liberality of the trusteès of the Percy Sladen Memorial Fund, I have been enabled during the past eighteen months to conduct a continuous series of excavations in the south-west corner of Messrs. Bolton and Laughlin's brickfield, Ipswich, where a well-marked "occupation-level" occurs resting upon a weathered surface of chalky boulder clay, and covered by a very hard and compact sandy loam of a greyish colour. It appears that since the people lived who occupied this " floor" the valley, which is now dry, has been deepened considerably, and as the "floor" passes into a small escarpment to the south at a depth of about 10 to 12 ft. from the surface of the ground, it seems that a considerable antiquity must be assigned to the human relics associated with it. The occupation-level under investigation is very rich in flint implements, which, in my opinion, must be assigned to the Moustier epoch. (Traces of another occupation-level occur above the Moustier deposit, containing implements of a totally different type which approximate to the earlier Aurignac examples.) With the flints have been found several hundreds of animal bones, representing chiefly the remains of the horse, and one specimen referable to the mammoth. Numerous fragments of very rough and primitive pottery occur in the floor, and tend to support Dr. Rutot's claim that about five hundred fragments of pottery were found at Caillou-qui-Bique, associated with an upper Le Moustier industry. Three portions of the human skeleton have been found scattered upon the "floor" with the flints and mammalian bones. These comprise a small portion of the upper margin of the occipital bone of a skull 10 mm. in thickness, the shaft of the left humerus of a woman, and the shaft of the right femur of a man. There seems little doubt that any of the bones found belonged to individuals of the Neanderthal race. All the human and animal bones are well preserved and in a condition of fossilisation. The excavations are still in progress, and it is hoped that further discoveries will be made. J. REID MOIR. 12 St. Edmund's Road, Ipswich, August 13.

highest possible amount during the period of hostilities.

The substances most needed are the aromatic hydrocarbons, of which benzene forms the base from which the newest and most powerful of these explosives, tetranitroaniline, is prepared, and also the tetranitromethylaniline, which under the name of "tetryl" is playing an important part in detonators and primers. Toluene, the next member of the aromatic group, is needed in enormous quantities to nitrate to trinitrotoluene, or T.N.T., whilst carbolic acid is the base from which picric acid is formed, this body under slightly varying conditions being the English explosive lyddite, the French melinite, and the Japanese shimose powder.

The aromatic hydrocarbons found in the coal-tar are only a small proportion of those existing in the gas, as the volatility of the so-called benzolsbenzene, toluene, and xylene-causes the largest proportion of them to be carried forward as vapour in the coal gas, and on cooling this gas and scrubbing it with creosote oil a much larger yield is obtained from the gas than from the tar.

The formation of these bodies is due to the action of heat on the primary constituents of the decomposition of the coal, and when coal is distilled at very low temperatures the primary products of the decomposition, which largely partake of the character of paraffins, i.e., saturated hydrocarbons, are found, whilst the aromatic hydrocarbons are to all intents and purposes absent. As the temperature of carbonisation is raised, the paraffin hydrocarbons become less in quantity, and naphthenes make their appearance in the tar. At still higher temperatures, these naphthenes split off hydrogen and become converted into aromatic hydrocarbons, such naphthenes hexahydrobenzene being converted into benzene with evolution of hydrogen. As the temperature

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of carbonisation is still further increased, the tendency is for these bodies to become converted into naphthalene, whilst the employment of very high temperatures with light charges gives rise to a tar which contains only very small traces of aromatic hydrocarbons, large quantities of naphthalene, and a very large proportion of free carbon, produced by the degradation by heat of the other hydrocarbons present.

When, however, vertical retorts and heavy charges with horizontal retorts were introduced, a marked improvement in the quality of the tar took place the heat from the walls of the retort passing slowly into the mass of coal distilled off the tar vapours at the lowest possible temperature, and these, finding an exit through the comparatively cool core of the coal to the mouthpiece, a large proportion of the lowest temperature tar was produced. As the charge became more and

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