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THURSDAY, SEPTEMBER 21, 1905. that radio-activity is a universal phenomenon, not
confined to a few substances :THE EVOLUTION OF MATTER.
"Mon premier mémoire sur la radio-activité de
tous les corps sous l'action de la lumière a paru dans L'Evolution de La Matière. By Dr. Gustave Le Bon. la Revue Scientifique de mai 1897. Celui sur la Pp. 389. (Paris : Flammarion, 1905.) Price 3.50 | radio-activité par les actions chimiques, a été publié
avril 1900. francs.
Celui montrant la radio-activité DR. GUSTAVE LE BON has written many books. fpomemée reescores ordemires a paru-toujours dans
Some twenty volumes, besides papers in current expériences par lesquelles les physiciens aient cherché scientific periodical literature, have issued from his à prouver que la radio-activité pouvait s'observer avec pen. History, travels, tobacco-smoke, anthropology, des corps autres que l'uranium, le thorium et le horsemanship, and psychology have in turn attracted radium n'ont été publiées par Strutt, McLennan,
Burton, &c., que de juin à août 1903.' his sympathetic interest. The work before us sets forth Dr. Le Bon's theories
We may first notice that Dr. Le Bon classes the of matter and energy, and contains, in a small-print effects of light under the head of radio-activity. This, appendix, an abstract of the experimental evidence it may be argued, is a matter of definition, and the on which he is content to rest those theories.
author is at liberty to give a meaning to the word According to the author, matter itself is merely radio-activity different from that adopted by all other a form of energy-probably vortex energy in the physicists. But it is well to point out that many luminiferous æther. Matter disintegrates—spon- experiments on the electric effects of the incidence of taneously in radio-active substances, but also under light on metals had been made before the year 1897, the influence of certain agencies such as heat or notably by Elster and Geitel between 1889 and 1895. chemical action, which are compared with the spark | Dr. Le Bon may have been the first to suggest that that fires a barrel of gunpowder. After giving rise the effects were due to the emission of particles, but to “ les produits de la dématérialisation de la matière :
no conclusive evidence was obtained until the experiions, électrons, rayons cathodiques, &c.," all things ments of J. J. Thomson and Lenard, in 1899, had finally pass into “ l'élément immatériel de l'univers :
determined the ratio of the charge to the mass, and l'Éther.” By the dissociation of matter, energy is identified the particles with those found in kathode transformed, and “c'est de l'énergie intra-atomique
rays. libérée par la dématérialisation de la matière que Secondly, doubt has been thrown on the emission dérivent la plupart des forces de l'univers."
of rays by substances undergoing chemical action by The chief experimental evidence on which Dr.
the recent experiments of Mr. N. R. Campbell, who Le Bon relies may be grouped under two heads :
has traced some, at all events, of the effects to (1) the emission of negatively electrified particles by secondary causes connected with the heat of reaction. metals when incandescent and when subjected to the Here Dr. Le Bon does not seem always to separate action of ultra-violet light; (2) the slight radio-activity clearly the ionisation which may be produced in a gas which may be detected in ordinary materials.
by contact with substances undergoing chemical The emission of negative corpuscles from metals change, and the emission of radiations, more or less under the influence of heat and light undoubtedly penetrating, characteristic of true radio-activity. occurs, though it is not to the author's speculative
Thirdly, in examining the spontaneous radio-activity opinions that we owe the experimental demonstration of ordinary materials, the author seems to underof the fact. As a speculative hypothesis, the idea that estimate the effect of the minute traces of radium the corpuscles are emitted during the disintegration which are now known to be distributed widely. He of the atoms of the metal is perhaps worth bearing claims Prof. J. J. Thomson's experiments on the in mind. But, on a review of the evidence known at
emanations emitted by various natural substances and present, it seems unlikely that the removal of these underground waters as a confirmation of his view that slow-moving negative corpuscles results in the in- all matter is radio-active. Now, Thomson found that stability of the atom from which they are derived.
the rate of decay and the phenomena of excited There is no evidence that an electric discharge activity in those emanations which he examined through a gas produces new elements, while the ions closely were about the same as those of the radium of liquids and gases, which result from the removal emanation, and his experiments should be regarded of the corpuscle, again yield the original atom when as an indication of the prevalence of radium rather neutralised. Such processes are to be distinguished than of the radio-activity of ordinary materials. It sharply from the irreversible changes which occur in is true that further experiments by Thomson, Cooke, true radio-activity, when bodies of atomic
Campbell, Wood, and others have now made it prob(a rays) or fast-moving corpuscles (B rays) are pro- | able that ordinary metals, at all events, are slightly jected. In this case, new chemical substances always radio-active. But, to eliminate the effects of strongly appear, and the process seems to be unaffected by radio-active impurities, it is necessary to take the heat, light, or any other physical or chemical agency. utmost precautions, both in the experiments themThis essential distinction is not noticed by Dr. selves and still more in the interpretation of the Le Bon, who assumes that the production of a cor- results. There seems little evidence that, in either puscle is itself a proof of atomic disintegration. respect, Dr. Le Bon recognised the necessity of such The author claims that he was the first to show precautions.
It will be gathered that the author takes a point The first two chapters deal with the people of the of view which is not that of the majority of physicists Færões and their mode of life, and will be found to who have investigated these subjects. Revolutionary contain a number of interesting observations on their opinions may prove a valuable tonic to the orthodox ethnography and the implements of the islanders. in physics as in other matters. It is not because he | The invasion of Iceland by the Moors in the sevenis heterodox that we are not satisfied by Dr. Le Bon's teenth century forms the subject of a third chapter, but book. It is because he seems to us to fail in grasp perhaps the most interesting part of the whole book is of the subject, to confuse phenomena which are that dealing with the wonderful bird-cliffs of the essentially different, and to be blind to evidence which Westman Islands, and the clever manner in which does not support his hypotheses.
the natives capture puffins and other birds in nets. A belief in the evolution of matter is fast becoming The fulmar appears, indeed, to be very valuable to not only possible but inevitable. Dr. Le Bon has the Westmaners, supplying them with both food and written readable speculations about that evolution, light. Other chapters deal with Iceland and its proand here and there has thrown out an interesting ducts, and the insects and domesticated animals of idea; but the evidence on which that belief must be both that island and the Færöes. founded is not that put forward by him. His Mr. Annandale deserves, indeed, our most hearty book calls to mind the advice offered by a famous congratulations, and has succeeded in producing a Lord Chief Justice to a brother judge, that it was most admirable little work which may be perused sometimes safer to give one's conclusions without with interest alike by the general reader and by the reasons which had led to them.
those who have enjoyed, or expect to enjoy, the opporW. C. D. W. tunity of visiting the islands he so happily describes.
Whether similar congratulations should be extended
to Dr. Marshall for his share of the work we are not THE FÆRÖES AND ICELAND.
fully assured. That gentleman seems, indeed, to be The Faeröes and Iceland; Studies in Island Life. under the impression that no one save Profs. Ewart
By N. Annandale. With an appendix on the Celtic and Ridgeway has written in this country on the Pony by F. H. Marshall. Pp. vi +238; illustrated. origin of the horse. Otherwise he would have (Oxford : Clarendon Press, 1905.) Price 45. 6d. scarcely credited the former with being the first to
regard Przewalsky's horse as a variety of Equus HE name of Mr. Nelson Annandale has been of
caballus. Neither would he have omitted to notice THE late years so intimately associated with the
that an earlier name than przewalskyi has been Malay Peninsula and its zoology and ethnology that suggested as referable to this animal, and also it comes somewhat as a surprise to find it on the title
that Prof. Ewart's E. celticus is probably inseparable page of a work dealing with such totally different
from the earlier E. hibernicus. Moreover, he might surroundings as those of the Færöes and Iceland.
have pointed out that it is difficult to understand It appears, however, that between the years 1896 and
how Prof. Ridgeway's new name of E. c. libicus can 1903 the author spent several summer holidays in
stand for the barb, when the Arab horse has long these remote islands, and contributed a series of
since received a technical name of its own.
R. L. articles on his experiences to Blackwood's Magazine and the Scotsman, and that it is these delightful articles, in a more expanded and elaborated form,
OUR BOOK SHELF. with the omission of certain purely technical details, Le Système des Poids, Mesures et Monnaies des which form the basis of the work before us.
Israélites d'après la Bible. By B. P. Moors. Pp. As Mr. Annandale suggests in his opening chapter, 62 +1 plate of figures and 6 tables. (Paris: A. most persons probably regard the Færöes as little Hermann, 1904.) more than mere Arctic rocks, teeming with sea-birds, The first part of this work consists of an inquiry in the ocean; and they will accordingly be surprised respecting the numerical value adopted by the to learn that, as a matter of fact, although lying the ratio of the circumference of a circle to its
Israelites at the time of Solomon for the constant s, nearly a couple of hundred miles to the north-west diameter. M. Moors obtains the greater part of his of Shetland, they enjoy a climate warmer than that material for this investigation from the dimensions of of many parts of Scotland, while their vegetation, if the “molten sea ” in Solomon's temple, as stated rarely more than a few inches high, is as luxuriant in I. Kings, vii., 23-26, and II. Chronicles, iv., 2-3. as the shallowness of the soil and the winter storms
These dimensions have led some writers--notably will allow. The buttercups, too, seem larger, and Spinoza and Hoefer—to the opinion that the Israelites
knew of no nearer approximation to r than the whole the bushes of a brighter green, than on the main
number 3. The specification of the molten sea is not, land. These islands have also to be regarded as however, sufficiently complete to determine its shape desirable spots, for it appears that although a few with any degree of certainty. Some commentators years ago they possessed a couple of dozen police have considered it as cylindrical, others have followed men, the moral of the population has been so excel- | Josephus in ascribing to it a hemispherical form, lent that the services of these guardians of the peace cylinder and parallelepiped. The author of this work:
whilst Zuckermann suggests a combination of were found no longer necessary, and the force has who is firmly of opinion that the Israelites accepted consequently been disbanded. A truly remarkable a value for * very close to 3.142, has found it necessary record!
in support of his argument to assume that the molten
sea had the form of a lipped cylinder. Adopting the risk of those untoward accidents which occur from description given in 1. Kings, which differs some- time to time, generally from ignorance of the properwhat from that of II. Chronicles, M. Moors has de- ties of the bodies dealt with.
J. S. S. B. duced for the cubic contents of the bath, a measure of
A Note-book of Experimental Mathematics. By C. capacity frequently met with in the Old Testament,
Godfrey and G. M. Bell. Pp. 64. (London : the relation
Edward Arnold, 1905.) Price 2s. 1 bath=ů (Mosaic cubit)".
This book gives concise instructions for carrying out
number of simple quantitative experiments in The remainder of the work deals with the system mechanics. It is specially suited for students who of weights, measures, and coinage in use among the intend to sit for Army Entrance Examinations, but Israelites. Carefully disclaiming any bias in ques. the excellence of the course outlined renders the book tions theological, he adopts the Bible as the chief
very serviceable for general use in schools; the authority on the subject of which he treats. The
students get accustomed to fundamental methods of weights and measures mentioned in the Bible are not,
measurement, obtain concrete conceptions of elemenhowever, always very clearly defined, and in attempt tary science, and secure much data well adapted to ing to combine them in a homogeneous system we serve as examples and illustrations in a course of are confronted with apparently hopeless incon- practical mathematics. The experiments include sistencies. Owing to this difficulty M. Moors finds measurements of lengths, areas, volumes, weights, it necessary to have recourse to materials of some specific gravities, fluid pressures, forces, moments, what incongruous character. From a strange medley velocities, accelerations, and many other physical of midwives, manna and mummies, he evolves, with quantities. A full and careful list is given of the much ingenuity, a series of metric equivalents for the requisite apparatus and fittings, and the book will be weights and measures of the Israelites. He claims of very great assistance to teachers in the arrangethat his equivalents are confirmed by all those ment of a thoroughly sound elementary course of passages in the Bible which contain references to experimental science. weights and measures. It is interesting to note that his value for the length of the cubit, viz. 443.61 milli
LETTERS TO THE EDITOR. metres, agrees very closely with the value obtained recently by Sir Charles Warren (17.64 inches, =
(The Editor does not hold himself responsible for opinions 448.05 mm.).
expressed by his correspondents. Neither can he undertake It is hardly possible to accept the view of M. Moors
lo return, or to correspond with the writers of, rejected that the Bible was intended inter alia as a text-book
manuscripts intended for this or any other part of NATURE.
No notice is taken of anonymous communications.) on mensuration. In spite of his laudable effort to throw light on the old Hebrew weights and measures
Cause and Prevention of Dust from Automobiles. they still remain dim to In the region of
The article on the above subject in the issue of NATURE metrology the Israelites would indeed appear to have
for September 14 (p. 485) is an important contribution to baffled the commentator, and to have buried their munity, but it contains a
a subject of great interest and importance to the com
statement with reference to authoritative standards " deeper than did
tar-macadam which in the interests of engineers should, plummet sound” out of the excavator's reach.
I think, be verified. Speaking of “Tarmac the writer So far as we have checked the numerical calcula
says, the slag is thoroughly impregnated, so that if the tions made by M. Moors, we have found them in- pieces are broken further a tarred surface is still found." variably accurate. There is, however, an obvious I have examined many specimens of tar-macadam, inmisprint in the last line of his letterpress; “ 43.5 cluding “ Tarmac.” I have never found any sign of should read “ 43,500.”
penetration of tar. I am aware that some believe in this alleged penetration, but it seems to be obvious that any
material sufficiently porous to enable tar to saturate it A Primer on Explosives. By Major A. Cooper-Key, would be totally unfit for road-making.
Edited by Captain J. H. Thompson. Pp. xii +94. That tar-macadam, and, of course, “Tarmac," have (London: Macmillan and Co., Ltd., 1905.) Price 1s. virtues for motor road-making may be admitted ; but this
penetration theory is not the reason, and it is a pity that This little book should prove of great value to those
the myth should still exist, as it tends to prevent the trial for whose benefit it has been mainly written, viz. the of other substances far more suitable for roads than furnace local inspectors under the Explosives Act, and those slag. dealers whose trading necessitates the handling and The reason why tarred granites and similar hard stones storage of explosives.
have not hitherto been found so effective is entirely a No one can better realise the want of some little matter of surface adhesion. Given a suitable tar mixture, handbook on the subject than H.M. Inspectors, and
there is no reason why hard, non-porous stone should not it is to meet this want that Major Cooper-Key has
be as efficient as slag. Penetration has nothing to do written this useful book, which, it is pointed out, is
J. VINCENT ELSDEN. “not a treatise on explosives." The author gives a
38 St. Stephen's Gardens, Twickenham. short description of the manufacture of the chief
In reply to Mr. Elsden, I agree that it is of no explosives, but its great value will be found in the
to hold mythical views. I think, however, that he is sections devoted to special risks with each class, the really mistaken in his views that the slag in “ Tarmac" methods of packing and storing, and a particularly is not penetrated by the tar. Possibly it may not be useful chapter on the general construction and penetrated by the most viscous constituents, but upon management of a store, the destruction of explosives, examining a broken piece of “ Tarmac " I have found that &c.
the surface is distinctly darker than that of slag which It is certain that a careful study of the book by has not been treated. The difference is very noticeable local inspectors will lead to a better understanding of
under the microscope, and if a bit of slag from the interior the whole question of explosives and the Act
of a treated portion is heated the tar is readily seen, generally, and hence to a more intelligent perform- tion by the tar takes place. I do not, however, suppose
which fact appears to be conclusive evidence that penetraance of their responsible duties. For those traders and users who have the handling of these goods after uniform material, and therefore in some parts the effect
that the penetration is very uniform, as slag is not a very they have left the manufactory the book should be might not be so evident.
W. R. COOPER. equally valuable, and it should do much to lessen the 82 Victoria Street, S.W.
THE SOLAR PHYSICS OBSERVATORY
It was not long, however, before many of us ECLIPSE EXPEDITION.
reached our camp. Rain had fallen about 4 a.m.,
and at about 6 a.m. another shower helped still Innsbruck, September 12. further to lay the dust, which had proved such a SINCE my last letter, which was dated August 26, menace to the smooth working of the clocks. The
I have had so little time for writing that I take previous evening all dark slides had been carefully the first opportunity to record the events that followed filled and noted with their particular make of plates.
and these now were distributed to the different workers.
Fortunately we were working in an area enclosed by a wall, so that only those who had received special permission could enter. Needless to say, invitations were numerous, and included the majority of those who had helped us in various directions during our preparations.
At the time of first contact, clouds near the region of the sun were very few, and we observed this under excellent conditions. As time progressed, a great bank of clouds was seen gradually working its way along from the west, and it became a race between the clouds and the moment of
second contact, i.e. the Fig. 1.- The officers of H.M.S. Venus volunteering for eclipse work on the quarter-deck.
beginning of totality.
The diminishing cresthe last communication. Passing over August 28 | cent became smaller and smaller at about the same and 29, which were spent in giving the final touches rate as the clouds over the sun became thicker and to the various instruments, putting in the eclipse thicker. The clouds won! The moment of second mirrors, and in rehearsing, we come to the eclipse day contact could not be observed! We went, however, itself. Turning out at 5 a.m, and scanning the sky, through our programmes, knowing that we were a glance showed that clear weather conditions for photographing nothing. Venus became a brilliant eclipse time were very doubtful. Heavy black clouds object in the west seen through a break,
6-inch prismatic camera.
16-feet coronagraph tent.
The tent of Lieut. Horne (Commandant
of Camp) and myself. Fig. 2.--Visitors being shown round the camp on the day before the eclipse. Looking west.
were sailing majestically across the zenith, and still Fortunately there were two currents of air at work blacker ones were slowly moving nearer the horizon. in the upper regions, one coming from the south and There were, however, small breaks here and there the other from the west. This intermingling of where blue patches were exposed for brief intervals,' currents was possibly the cause of the thinning of but it seemed that the chances for a clear eclipse were the clouds over the sun, and gave us a view of the very small.
corona for brief intervals through, as it were, a thin
veil; the clearest intervals were towards the end of the poles. At the north pole there was a region distotality. The burst of sunlight from the north-west playing the beautiful rifts
best during limb of the sun heralded the end of totality, and thus eclipses at a minimum stage, but at the southern pole ended the work of the instruments and the greater no such distinctive structure was seen. Unfortunately majority of the different parties.
the eastern and western limb of the sun were shrouded We were all, however, bitterly disappointed. So in thicker haze than the north and south region at much trouble had been taken to make everything work the time that I had my longest glance. It was therewith the maximum of efficiency, but, alas! with so fore about the solar poles that the longest streamers.
small a result. Prismatic cameras of high dispersive were seen by me, and two in the south-east quadrant power and prismatic reflectors of long focal length, extended for at least two solar diameters. to say nothing of long-focus lenses for three-colour The eclipse being over there was then nothing negatives, are not conducive to good results in a more to do than to collect all the photographic plates cloudy sky !
exposed and commence with the packing up of the During the few moments that were available instruments. It is one thing to set up the instrubetween the exposures of the different plates in my ments and another to take them down. By the eveninstrument I saw enough of the corona to know what ing of the same day about 50 per cent. of the packing a magnificent sight it would have been had it been up had been completed.
Siderosiat. Tube of 6-inch Packing cases supporting Cusp Three-colour camera
prismatic camera. small cameras with gratings. telescope. in distance. Fig. 4.-The 6-inch prismatic camera, showing staff and positions for the small grating cameras and the cusp telescope.
seen in a cloudless sky. The enormously brilliant red In the cool (?) of the evening the development of prominence in the north-east quadrant was an un- the plates was commenced. Those which promised doubted feature of this eclipse, and nothing like it to have some kind of record on them were taken first. was seen by me in either the 1898 or 1900 eclipses. To sum up the results, now that the whole set has From several accounts the landscape was illuminated been developed, it may be said that we have been far by this red radiating object, and sunset effects were more fortunate than was at first anticipated. The recorded by other observers.
prismatic reflector worked by Mr. Butler succeeded The corona itself was of the maximum type, in securing an excellent picture of the lower corona, streamers radiating in all directions even very near the solar diameter being about 8} inches. The 16-feet