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THE GEOMETRY OF FORCES.

Observing that the laws for the composition Geometrie der Kräfte. By H. E. Timerding. Pp. twists and wrenches are identical, the author, 25

xii +381. (Leipzig: B. G. Teubner, 1908.) Price others have done, uses the word dyname to signi 16 marks.

either a twist or a wrench. For a large part of it: IN N this admirable volume Prof. Timerding gives a

subject the use of the abstraction signified by the systematic and original treatment of the geo

word dyname is very convenient, and considerat': metry of forces and force-systems in which for the

use has been made of the important labours of Stus first time, so far as we are aware, an adequate know

on the geometrical theory of dynames. ledge of modern geometrical research has been utilised

In an interesting chapter on “Die Reyesches in a text-book of mechanics.

Strahlencomplexe " the author brings into its diEver since the great work of Plücker, that large prominence the fundamental importance of and most attractive department of mathematics known

Geometrie der Lage" in kinematics. This chap:as the geometry of the linear complex has been found contains many admirable theorems, and we could on to be intimately connected with the geometry of forces.

wish that such instructive and beautiful ideas as ar It is sufficient to recall the fact that whenever six

here set forth were more generally introduced ir: forces applied to a free body are in equilibrium, the

the teaching of mechanics. Due acknowledgment: forces must lie respectively on six rays of a linear com

made throughout the work of the important contrito plex. In chapters viii. and ix. of Timerding's book tions to the geometrical theory of forces by the la

:now before us we have an admirable treatment of the

Prof. Charles J. Joly. application of the theory of the linear complex to the

The chapter on the cylindroid may be specially cortheory of systems of forces. The many interesting

mended, and prominence is given to the theorem thz. matters set forth in these pages show how greatly the

the projections of any point on the generators of : advancement both of the geometrical theory and the cylindroid lie on an ellipse. We may, however, he's dynamical theory is promoted by their association.

that the proof here set forth is not that by which tb The statical and dynamical significance of the linear theorem was discovered, as shown in the origina complex is closely connected with the fact that each

volume on the theory of screws published in 1876. ray of the complex is reciprocal to that screw of which

A sufficient account is given of the various syster. the axis is the axis of the complex, while the pitch of of screw coordinates, and, following the analogy the screw is the parameter of the complex. Many of

the resolution of forces, Prof. Timerding uses nos. the geometrical properties of the complex follow directly tion which divides the coordinates of a screw in: from this general principle. For example, on p. 107

two groups of three each. It is, however, often oc". it is shown that four linear complexes have two real

venient to use the six symmetrical coordinates of a or imaginary rays in common. This is an immediate

screw referred to six co-reciprocal screw's. consequence of the fact that one cylindroid can always

We are glad, indeed, to commend this most excebe found of which every screw is reciprocal to any

lent work to the attention of teachers and students o four given screws. As there are two screws of zero

theoretical dynamics. We are sure that if the bon pitch on the cylindroid, these lines are, of course, the

were translated into English it would form a ver two common rays of the four linear complexes defined

valuable supplement to the existing English books as being reciprocal to each of the given screws. We

It would give the student an adequate idea of th: congratulate Prof. Timerding on his recognition of extent to which modern geometrical theory and th the proper place for the linear complex in the fore theory of forces act and react on each other to the vas front of a text-book on the geometry of forces.

benefit of both.

ROBERT S. BALL The theory of screws has received in this volume a treatment even more ample than that which it has already received in the works of Fiedler, Schell, Budde,

THE DISTRIBUTION OF GOLD ORES. Minchin, and more recently in the “ Encyclopädie der

Gold: Its Geological Occurrence and Geographic: mathematischen Wissenschaften." The excellent

Distribution.

P

By J. Malcolm Maclaren. work of Harry Gravelius, “Theoretische Mechanik

xxiii +687. (London: The Mining Journal, 1908. Starrer Systeme,!' contains a complete account of the

Price 255. net. theory of screws up to the date of its publication in DR. MACLAREN begins his preface with thi 1889. Much of the work done on the subject in the

“ad: succeeding decade has been available for the “ Geo

treatise the literature of metrie der Kräfte.It may, however, be remarked study of ore-deposits must needs show justifthat certain developments of the theory which have cation." Any apology for the publication of his appeared since 1900 have not been included in Prof. useful book is, however, quite unnecessary, for the Timerding's volume. The theory of screw-chains, by increase by four times of the gold yield of the wori which the theory of screws has been extended to any during twenty years has been attended by a volumirmaterial system, is also not discussed. A suggestive ous and scattered literature. Students of minir. reason for this omission is given in the preface (p. vii), geology will be grateful to any author who undertakes where Prof. Timerding says that, in his opinion, the the great labour of compiling a summary of recen theory of screw-chains would require a new and

work on gold and its distribution. voluminous treatment of the whole of mechanics in The longest and most valuable section of Dr. Macwhich the rigid body would appear as the first element. laren's book is occupied by an account of the geologica

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structure and mining history of all the chief goldfields admits that the nuggets of Western Australia are
of the world. This part of the work occupies 544 derived from gold-quartz veins, and the evidence for
pages. The goldfields are classified by continents. the similar origin of the nuggets from Victoria-
Those of Europe are described first, and in proportion which contains the most famous of nugget-yielding
to their economic importance receive longer notice than goldfields-seems to the writer overwhelming.
those of Australia and South Africa. The longest section Another doubtful hypothesis advanced by the author
is that on the goldfields of North America. Each field is the absence of any undoubted, valuable pre-

is noticed separately; the descriptions are necessarily Cretaceous placer deposit. He rejects, or quotes with hor trimes a short, but they are concise, and are accompanied by apparent approval those who reject, the alluvial origin tal impuria, useful reference to recent literature. The minor fields of the gold in various Mesozoic, Palæozoic, and Archæan

are described at relatively greater length than the conglomerates and sedimentary deposits; and he then orems, and in others; and thus Kalgurli, with its “Golden Nile,” is argues that the absence of pre-Cretaceous detrital gold nd beauti

, dismissed in four pages, including a full-page map is due to the rocks having been lowered into a zone Zenerally and another figure.

This distribution of space is, saturated with alkaline waters which removed the gold Due actor however, probably the most useful, as the less-known

in solution and re-deposited it in veins. f the impre fields are often very instructive and their literature is Though many geologists may be disposed to differ ory of free less accessible. The author has travelled extensively, from the author in some of his conclusions as to the

and his accounts of many fields have the advantage formation of gold ores, they will be no less grateful id may less of personal knowledge and original information. The to him for this valuable and trustworthy summary of iven to the descriptions of the fields are therefore inevitably of the voluminous gold literature issued during the past on the gener unequal merit.

twenty years.

J. W. G. map

, tip Among the most interesting sections are those on s not that ), the mines of New Zealand-though

New shown ia » Zealander, it is strange that the author places Reefton

SWINE IN AMERICA. s publisheri': in Westland, and spells the name of the founder of the Swine in America. A Text-book for the Breeder, 1 of the kn. New Zealand school of mining geologists Chlrich-of Feeder, and Student. By F. D. Coburn. Pp. llowing the Queensland (the author was once on the staff of its XV+614. (New York : Orange Judd Co. ; London : Timerdic

; Geological Survey), and of Mysore. The historical Kegan Paul and Co., Ltd., 1909.) nates of ar introduction to the Mysore gold mines is of especial UST as it might be said of the British fat bullock is, however interest, and the author rejects the view that the that he has followed the turnip, so it might be

ancient mines there can have been those from which said of the American fat hog that he has followed the cal screws Solomon and the Phænicians obtained their supplies corn, i.e. Indian corn. In the United States there mend this * of gold. Dr. Maclaren remarks that India was then are 56 millions of swine-there are only three and a achers and a civilised State, which needed more gold than it pro- half millions in the United Kingdom-and far more sure that duced ; and the Israelites could only have obtained gold than half these are to be found in the great corn States it would Ar there by barter, for which they had nothing to offer. which are drained by the Mississippi and its tribuisting Erwin This conclusion, therefore, strengthens the view that taries. Iowa comes first with 8.1 millions, and Illinois adequate the Ophir of the Phænicians must be in southern and Nebraska next with 43 and 41 millions. Altotrical char Africa, and that the gold probably came from the gether there about eighty million pounds' each oth prehistoric mines of Rhodesia.

worth of swine in the United States, the duty of which ROBERT Dr. Maclaren's account of the separate goldfields is it is to convert corn and other crops and by

preceded by an introduction on the chemical and products into marketable commodities, and

physical properties of gold, on natural and artificial eventually to feed, not only the Americans, but also * GOLD I compounds of gold, and on the theories of the forma- some part of the industrial population and the armies e and 6. tion of gold ores. The speculative section of this in- and navies of the rest of the world. m Macre troduction is remarkable for the author's advocacy of An industry so vast can do with many a text-book, Fring frame

somewhat extreme positions. Thus he denies the and Mr. Coburn has produced one for those who origin of any important ore deposits by other agencies breed, rear, and feed the raw materials for the

than meteoric waters. He admits that there may be American packing houses. Many experiments have = preface

some magmatic water; but even when he allows that been carried out in the States on the rearing and

the gold is due to magmatic emanations, he holds that fattening of swine, and the gist of these is embodied literature

the water in which it is dissolved comes from a super- | in Henry's “ Feeds and Feeding," which, however, eeds shorn

ficial source. He also holds to the once popular view is a book dealing rather with principles than with the publicains that alluvial gold and gold nuggets are formed by details of management, and a book, therefore, for the

growth in situ in the gravels from percolating gold- student rather than for the farmer. Mr. Coburn's is vieido e bearing solutions. He defends this view especially on a farmer's book. He has collected Henry's and many nded by: the ground of the crystalline character of much alluvial other data, and set them forth in such a way that the uden's

gold; he quotes competent authorities who deny this nutritive effect and economic value of every important por aho: fact, but affirms it from his own experience. The feeding stuff and by-product is dealt with, whether ummate author does not explain why, on this precipitation these foods are fed separately or with others. The

theory, nugget formation is so local, and why the effects of bulky and succulent foods and of concenctica dil nuggets are so constantly found just below the out-trates, and of these consumed separately and jointly, ut of the crop of reefs containing nuggety patches of gold. He are fully considered. Thus, for instance, a farmer

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having a lot of corn is told what proportion of alfalfa, causation of tumours are summarised. As regards thor roots, ought to be fed along with corn to attain the latter, one or two points brought out by recent rebest economic results. This part of Mr. Coburn's search have been omitted. For example, the occur.

rence of heterotype mitosis in malignant growths : book is valuable.

referred to, but Bashford and Murray's criticisin In the earlier chapters Mr. Coburn deals with the Farmer, Moore, and Walker's work in this connectivarious races and breeds of swine in the States, and does not appear, and in discussing the supposed saro» also with the principles of breeding; but, as may be matous metamorphosis of carcinoma no mention :inferred from the following quotation, although he made of the fact, which now seems certain, that it writes at some length, he does not get much beyond the connective tissue stroma of the carcinoma whic

is thus transformed, and ultimately overgrow's the cr. the current nebulous ideas held by stock-breeders on these subjects :

cinomatous elements. The vegetable parasites as

omitted, as these are dealt with in text-books of ba.. " There exists in some sections of Old Mexico a type teriology, but an excellent and fairly full account of 'hog'which is the product of crossing a ram and given of the animal parasites, protozoan and mtira sow, and the term 'Cuino' has been applied to this zoan.

Immunity is discussed in twenty-five pags: rather violent combination. The ram used as a sire and the essentials of the subject are conveyed to the to produce the Cuino is kept with the hogs from the reader. time he is weaned. ... The Cuino reproduces itself On the whole, the book may be regarded as a res and is often crossed a second and third time with a useful text-book of general pathology. It is excellent

got up, and a word of praise must be bestowed on A number of the illustrations are not accurate illustrations, 162 in number (also four coloured plates representations of the breeds they refer to, but are

the majority of which are the work of Mr. Richar.

Muir, and as a rule depict very clearly the subjects rather artist's ideals.

they represent, though it may be questioned wheth

so many are really necessary, as they tend to distra OUR BOOK SHELF.

the student from examination of the

specimens themselves. A Text-book of General Pathology for the L’se of

Students and Practitioners. By Prof. J. M. Beattie (1) Der Bau des Weltalls. By Prof. Dr. J. Scheine and W. E. Carnegie Dickson. Pp. xvi + 475

Dritte, verbesserte Auflage. Pp. 132. (Leipzis (London : Rebman, Limited, 1908.) Price 175. 6d.

B. G. Teubner, 1909.), net.

(2) Die Planeten. By Dr. Bruno Peter.

Pp. 13: In the preface the authors state that this volume is (Same publishers, 1909.) Price 1.25 marks each. based on the teaching of the Edinburgh school of (1) The series “ Aus Natur und Geisteswelt" is wt. pathology, where the first chair of pathology in the known. It consists of a number of little treatises, United Kingdom was founded, and as such we wel which men of science occupying prominent positiors come its appearance. At the same time, we do not have attempted to explain in an accurate and cutnote any features particularly novel, either in the prehensive manner the results of past inquiries, ar: subject-matter or in its arrangement, and in some ihe position to which our knowledge has extended in respects the book seems to be lacking as a text-book various directions. In the former of the two specimer.s of general pathology. Thus the important factor of before us, Dr. Scheiner gives the substance of si: heredity in disease, and shock and collapse, are not popular lectures delivered in Berlin to a number i; even mentioned, and we do not understand why a high-school teachers in the course of which : discussion of the nature of gout and the chemistry of attempted to describe so much of the universe as coruric-acid metabolism“ do not come within the scope within the range of our telescopes. He endeavoured of the present volume."

to bring home to his audience the magnificent scher: The opening chapter deals all too briefly with the of distances on which the planetary and stellar sin cell in health and disease. An excellent summary of tems are planned; he traced the detection of proper modern views on cell-structure and cell-division is motion of the fixed stars, and showed how the sun presented to the reader, but the section on the chem- movement in direction and amount can be determiner istry of the cell is mainly occupied with the recom- The phenomena of the sun are explained in som mendations of the Chemical and Physiological Societies detail, preparatory to the examination of the spectr. on protein nomenclature.

of stars, a subject which is discussed somewhat ful: The chapters which follow deal respectively with as might be expected from a member of the staff i; general retrogressive processes, disturbances of the the Potsdam Observatory. Herein, as the author circulation, inflammation and repair, progressive tissue points out, he is on the sure ground of observation changes, animal parasites, and immunity.

But in his last chapter he approaches the more spectAn excellent account is given of fatty change, and lative subject of the origin and constitution of the modern views respecting it are succinctly stated. Lar- universe. The subject is handled with skill, and, nodaceous disease is similarly well treated, but we do not withstanding the limited space to which the auth: understand why authors will persist in employing the is restricted, he has succeeded in making his subjet terms “

waxy and “amyloid” to designate it, for both clear and interesting. We do not wonder that "lardaceous” has the claim of priority; it is official the little work has passed through three editions, for in the “Nomenclature of Diseases of the Royal apart from that longing to satisfy an intelligers College of Physicians, and the material present is curiosity which appeals to so many, the material i. universally known as lardacein.

put in a very attractive form, which should appeal ti The chapter on inflammation and repair gives all

many readers. essential details on this important subject. The classi- (2) Dr. Peter has a simpler subject, in which the fication of tumours, admittedly a difficult subject, facts have been many times detailed, and he has litt's adopted by the authors is that advocated by Adami. scope for either originality of treatment or lucidity This seems to us unnecessarily complex for the medical arrangement. As the planets extend in order from the student and practitioner. The structure of tumours sun, so he must follow them from Mercury to Neptune is given at some length, and the chief views on the A Vulcan is hinted at within Mercury's orbit, but the

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JULY 8, 1909)
NATURE

37 its brought . hypothetical planet outside Neptune does not attract well known that these properties, while still remainosis in malige come under notice, more attention might have been

comment. Since the satellites of Jupiter and Saturning additive, involve factors depending on the constid and Murrais given to the moon and to the phenomena of eclipses. | formation, &c., all of which should be taken into

tution of the molecule, e.g. method of linking, ringif carcinoma planets, though naturally the tale of the discovery of thorough-going application of this principle in the

description of the surface than of the motion of the property in the case of any given substance. It is the now seems ceris Keptune is told once again. It might seem that there calculation of thermochemical constants, extended so as

is scarcely room for such a book, considering the to include, not only the specific thermochemical values ultimately the number of popular works that are extant, but there of double and triple bonds, but also the thermal value he vegetable is some difficulty in keeping even these works abreast of the strain” in ring-compounds and of the single with in ters of the time. As an example we may quote the sen- bond in chain-compounds, that the book under review and fairy is tence, "Bestimmt sieben, wahrscheinlich sogar acht expounds. The author's method of calculation has

Monde umkreisen. Jupiter." Notwithstanding the already appeared in several articles published in the

recent issue, there is here opportunity for correction Chemical News, on which the present monograph is subject are in the next edition.

based. l'ntersuchung und Nachweis organischer Farbstoffe

The author's method will best be understood from auf spektroskopischem Wege. By J. Formánek, the following :-Let H be the value of a hydrogen with the collaboration of E. Grandmougin. Pp. 252. atom plus the link joining it to a carbon atom. Let Second edition. Part i. (Berlin : Julius Springer, C be the value of a carbon atom, not including the 1908.) Price 12 marks.

value of its valencies; let L, L., Lg, be the values the work of li The first edition of this work appeared in 1901 in a

of the single, double, and triple bonds respectively. t very cleatssingle volume. In part i. of the new edition which is Knowing the constants for four "hydrocarbons, it is lay be qu'in now before us, subject-matter to which only forty-two possible to calculate the value of the following :!, as they tes pages were devoted in the first edition has been C+4H=a, 2H-L, =B, 4H - L,=y, 6H-Lg=8. These mination elaborated and added to so largely that it occupies the

fundamental constants for carbon and whole of part i. The introduction deals with spectro-hydrogen. Moreover, the formula of any compound scopic methods in general, but more particularly with

can be written in terms of these fundamental conBi Prof. Dr. i absorption spectra of coloured solutions and the influ- stants, and the theoretical value so obtained can then se. Pp. sua ence of solvents, concentration, reagents, temperature, be compared with the experimental number. &c., on the latter. Then follow chapters on the spec

This method the author has illustrated by the calBruno Pile troscope, general observations on the relationship culation of a large number of heats of combustion of Price 1.3 128 between colour, absorption, fluorescence, and constitu- substances belonging to different groups of compounds, und Geisention of coloured compounds and dyestuffs, and on the and, with comparatively few exceptions, excellent coniber of ladies relationship between chemical constitution and absorp- cordance with the experimental numbers has been

tion spectra of dyestuffs belonging to individual classes. obtained. In this fact the method has its justification. The latter include di- and tri-phenylmethane dye

In an interesting section the author discusses also stuffs, quinonimide dyestuffs, fluorindene and tri- | the relation between heats of combustion of ring-comOwledge has a phendioxazine, acridine dyestuffs, and anthraquinone pounds and von Baeyer's strain theory, and he shows

that in general there is perfect agreement. No simple dyestuffs. No mention is made in this part of the azoner of the T -s the x dyes, or the dyes of the indigo group, while of natural relationship, however, has been obtained between the Berlin

dyestuffs only alizarin is mentioned. It is to be pre- angle of deviation and the thermal equivalent.
sumed, however, that these important classes will

The book is one which deserves and will no doubt Coury US

receive due consideration in part ii., which represents obtain the attention of all who are interested in the the practical part of the work.

relations between the thermochemistry of compounds opes. He is

Although a vast amount of work has been done and their chemical constitution; and the method of the

by different observers on the absorption spectra of the calculation is, moreover, one which will not improbably netary and

organic dyestuffs, the information is so scattered as to he detitie

find application in the case of other physical properties be difficult of access to the ordinary individual, and

of an additive character. It is an important addition showed this is probably the main reason why this important

to the literature of thermochemistry.

A. F. aint can it e subject has hitherto not received the attention which

An Angler's Season. By W. Earl Hodgson. Pp. pe explain it merits. There is, however, ample testimony that this ination of a particular application of the spectroscope is being more

xii + 299. (London : A. and C. Black, 1909.) Price

35. 6d. net. used in and more appreciated by the manufacturers of dyestuffs A BOOK from Mr. Hodgson is always worthy of the member it on the one hand, and the users on the other. This erein, 3: is borne out by the fact that such an eminently prac. exception to the rule.

angler's attention, and “ An Angler's Season " is no round t * tical body as the Société industrielle de Mulhouse has

Dealing as he does solely aches the made a pecuniary grant to the author to enable him

with salmon and trout, and almost entirely with I constiut to publish the new edition. Prof. Formánek has

Scotch waters, the author's season begins in January with 4 made a life-long study of his subject, and a compre- allotted; throughout there is much good reading, a

and ends in October, and to each month a chapter is co wtita hensive and up-to-date book on this particular applica- deal of 'sage advice, and some controversy. Early in

makini tion of spectrum analysis, such as the present edition do nas promises to be, would be much appreciated. It is to

February Mr. Hodgson is already at issue with the 7 throu na be hoped that the completion of the work will not be dry-fly fisherman, and his attack on the “ Hampshire tisfy as long delayed.

method ” waxes furious, but he says nothing of those

who fish with the dry fly in Aberdeenshire waters and On the Calculation of Thermochemical Constants. find the method successful. Fault is also found with ch shiuks.

By H. Stanley Redgrove. Pp. viii+ 102. (London : some anglers for their “habitual indifference to the
Edward Arnold, 1909.) Price 6s. net.

weight of a basket " and their love of nature; surely bject. in * There are a number of physical properties of sub- an angler no worse for also being a naturalist, or

stances, e.g. molecular heat of combustion, at least taking an interest in the natural history of fractivity, &c., which are chiefly additive in character, fishes. A study of what naturalists have written so that their values can be calculated if we know the would have shown the danger of Mr. Hodgson's necessary fundamental constants. It is, however, also theory that taking large fish only, and restoring all of

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smaller size to the water, would have the effect of recording apparatus where a light source is far from increasing the average weight of the stock of fish in recording surface, a thick line may obscure any 1three years' time, and would, we think, have pre

movement. These instruments are therefore unsuitabit vented the red flesh of some trout being attributed to

recorders of very small movements. This, at any rate, richer feeding rather than to a differently constituted

been my experience.

The British Association type of instrument, menu. We think, too, that the theory set forth to

properly adjusted and installed, does, however, pick account for the absence of a run of salmon in some

these neglected movements--a result which is shown ter rivers of the east of Scotland in May, June, and July clearly in the registers for this year. is somewhat strange, and cannot be maintained in the It seems to me that beneath observatories all over light of our present knowledge of the salmon's life- world earth-messages may be passing every few mint: history.

but these are not recognised because instruments gent? There are throughout the book numerous practical in use are not capable of recording the same. To invest hints of value upon such subjects as flies and baits, gate this possible new departure in seismology, oid it and as to the time and place for fishing under various

of instruments will have to be improved or conditions of water and weather; in the last chapter

adopted.

JOHN MILNE

Shide, Isle of Wight, July 2. there is also a most thrilling tale of a riverside adventure. The illustrations, reproduced from photographs,

Tables of Bessel Functions. are excellent, but are almost invariably separated by

A COMMITTEE of Section A of the British Association for many pages from the corresponding text, and there is

the Advancement of Science, appointed to undertake a good index.

L. W. B.

further tabulation of Bessel functions, is at present ce

sidering the advisability of unifying and completing • LETTERS TO THE EDITOR.

existing tables with the view of the publication of

complete table of Bessel functions. [The Editor does not hold himself responsible for opinions expressed by his correspondents. Neither can he undertake

The committee would be glad of information as to erke.

ing tables of Bessel and Neumann functions with a ra to return, or to correspond with the writers of, rejected manuscripts intended for this or any other part of NATURE.

or complex argument, in addition to the following,

which the members are already aware : No notice is taken of anonymous communications.]

(1) Meissel's Tables (reprinted in Gray and Mathem: A New Departure in Seismology.

treatise on Bessel functions) giving J (x) and J.(x) iro. On the photographic records obtained from British

x=0 to x = 15-5 at intervals of 0.01 (12 places); also Association types of seismograph it has been noticed that

table of the first 50 roots of the equation J1(x)=0 when the films have been moving slowly (60 mm. per

16 places.

(2) British Association Tables (1889, 1893, 1896 Repor: hour) there have been slight thickenings in the trace, while if the recording surface has been moving quickly (240 mm.

giving 1.(x) and 1,(x) from x=0 to x=5.1 at intervak! per hour) the line which ought to be straight is slightly

0.001 [9 places); also 1,(x) to 11(x) from x=0 to 23h. wavy. These irregularities, which have hitherto received

at intervals of oz (1 and 12 significant figures] : also but slight attention, are so small that they may be easily

table of J.(xvi) from x=0 to x=6 at intervals of v: overlooked. When the thickenings were first observed it

19 places). (Part of these tables are reprinted in GT3 was supposed that their existence was due to a flickering

and Mathews.) at the source of light or to some irregularity in the move

(3) Tables of Ln(x) in Gray and Mathews from n=0

and from x=0 ment of the record-receiving surface. When, however, it

to x=24 at intervals of unwas observed that these markings frequently occurred at

(18 places). the same time at different stations, as, for example, at

(4) B.
A. Smith's Tables giving Y.(x),

-Y,111 Shide and Bidston, the conclusion was that they were due

(log 2-w)J.(x) - Y.(x) and (log 2-6)} (x) - Y,(x), fren to movements of the ground, and might be the surviving

x=0 to x=1.00 at intervals of 0.0i and from x=1:1 phases of large movements with origins at a distance.

x = 10.2 at intervals of 0.1 [4 places : error not exceedings A very good illustration of this is given by comparison of

2 in the last place). (Messenger of Maths., vol. Ir. the times of occurrence of the after-shocks which followed

1897, and Phil. Mag., vol. xiv., 1898.) the earthquake of January 14, 1907, in Jamaica, with the

(5) Aldis' Tables of 1.(x), 1,(x),' K.(x), K,(x) from times at which suspicious irregularities were found on the

x=0 to x=11 at intervals of 0.1 (16 places). (Roy. So. seismographic traces at Shide and Bidston. Between

Proc., 1896 and 1899.) January 14 and July 5, 148 shocks were noted in Jamaica.

(6) J. G. Isherwood's Tables of K.(x) to K.(x) froz Forty-three minutes after the occurrence of fifty-one of

x=0 to x=5 at intervals of 0.2 15 significant figures these shocks irregularities were found on the films at the

(Manchester Lit, and Phil. Soc., vol. xlviii., 1904.) stations mentioned. As forty-three minutes is the time we

The committee will be grateful to be allowed, througi should expecta “ surface" wave to travel sixty-seven

the medium of Nature, to invite any readers who a: degrees, or from Jamaica to England, the inference is that

aware of the existence of tables of Bessel functions other the slight irregularities represent movements which had

than the above to make known this fact. their origin in Jamaica. Corresponding markings, with

Communications should be addressed to the secretary the exception of one at Göttingen on July 5, do not appear

the committee, Dr. L. N. G. Filon, University College, in the registers from European stations, which are not

Gower Street, W.C.

M. J. M. HILL more than six or seven degrees farther from Jamaica than

University College, Gower Street, W.C.
Britain.
Another instance of the recording of after-shocks are the

Baskets used in Repelling Demons. markings seen on seismograms after the disaster which, on In the issue of NATURE published on May 27 N: December 28, 1908, ruined Messina and Reggio. Between Kumagusu Minakata inquires regarding the use of basket December 29 and January 30 at Mileto, forty miles from in repelling demons in countries other than Japan. 1: Messina, 22; shocks were noted. Eight of these reached Calcutta, and I believe in other parts of India, it is the Isle of Wight, while on January i and 13 at Göttingen, customary when a new building is being erected to set up Hamburg, and Laibach, only two were noted. The reason on the highest part of the scaffolding a pole, to the too that so small a number travelled a considerable distance of which a round basket and a scavenger's broom af indicates that the originating impulses were weak. That a attached. The basket and broom are apparently recognisd larger number should be recorded in Britain than at com- as emblems of the low-caste “ sweeper," and therefore a paratively near stations is not so clear.

being disgusting objects. They are supposed to ward ci With smoked paper recording surfaces, whether the ill-luck from the building. Their use in this instance day multiplication of recording levers be 10 or 200, a certain thus be compared to the use in many countries of obscere slackness in joints and elasticity of pointers prevents any objects or gestures as a protection against malicious spirits record of motion being obtained until a certain amplitude

or the evil eye.

N. ANXANDALE. of ground motion has been reached. With photographic Indian Museum, Calcutta, June 13.

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