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were shown to be the result of the flux and reflux of The land regions (Germanic and Lusitanian) yield waves of heat as hotter or colder years alternated, the probably something under 300 species. The last trusteffects of which were by no means eliminated in the five worthy work, that by Moquin-Tandon, describes 266 or six years over which the record extended. But the species-219 being terrestrial and 47 fresh-water forms. remarkable diminution of temperature from the surface The marine provinces are the Celtic and Lusitanian. down to 1 foot cannot be thus explained. It appears The former includes the greater portion of the English at all the stations, for even at Calcutta there is an increase Channel, and is common ground, therefore, to ourselves of only o®2 in the first foot below the surface, and then an and our neighbours. The latter, especially the Mediterincrease of ro3 between 1 and 3 feet ; and it appears to ranean as distinguished from the Atlantic version of it, be independent of the character of the surface, which at furnishes the French conchologist with his happiest Calcutta is grassy, and at Jeypore pure sand absolutely hunting-ground. Nearly 1200 species are to be found in without vegetation. At Calcutta and Allahabad, the 1-foot the Mediterranean, and another 150 (besides 418 common thermometer as originally installed was found to have its forms) on the Atlantic coast. temperature lowered by air-convection at night in the tube In contrast with this abundance of Molluscan life, all around the thermometer ; but steps were taken to prevent that we can boast is some 550 marine and 130 nonthis both at these and the other Observatories, and the marine species. invalidated registers were rejected. Yet it is difficult to Whilst, however, the material obtainable by the French imagine the existence of any cooling agency which should conchologist is thus plentiful, the literature at his disposal keep the temperature at i foot below the surface on an for purposes of research and identification is by no means average ro or 2° lower than eitber above or below that so complete as that which lies ready to the hand of his level, and the matter certainly requires further investiga- British confrère. The French Forbes and Hanley, or tion.

even Jeffreys, has yet to be compiled ; no single work The foregoing remarks deal with subjects which, exists giving adequate descriptions, with synonymy, notes, although intimately connected with meteorology, lie and figures. somewhat apart from the ordinary field of meteorological For the non-marine species Moquin-Tandon's careful observation. There is, however, very much in Mr. work remains unsurpassed : for the whole subject the Eliot's Report, on the more familiar class of subjects only approach yet made consists of the three volumes by usually dealt with by meteorologists that is well worthy M. Locard, of which the one now under consideration of reproduction, especially the characteristic phenomena forms the last. The first two were issued under the title of Indian storms, which Mr. Eliot has made the object “Prodrome de Malacologie Française, Catalogue général of his special study. These must be reserved for another des Mollusques vivants de France," and dealt respecnotice.

tively with the land, fresh- and brackish-water Mollusca, The frequent reference in the foregoing paragraphs to and with the marine. In these volumes the author gave the admirable work of the late Prof. Hill (and, after all, no descriptions: a synonymy of each species, with referbut few of the many subjects have been noticed to which ences to the best descriptions and figures, and a list of his active mind contributed so largely) forcibly brings the French localities, were all that appeared. In the before me how great a loss has been sustained by Indian present work M. Locard proposes to supply this descience in his premature death-a loss the more con- ficiency, so far as the shells of the marine testaceous spicuous in a country where the workers are so few and Gastropoda, Pelecypoda, and the Brachiopoda are conthe field of research so large and fruitful. It is but a sad cerned, by furnishing a concise-mostly too conciseconsolation to offer this slight tribute to the memory of a description of each species, and a more detailed descripman who was as modest and amiable as he was able and tion, with a figure, of the typical forms of each genus and accomplished as a devotee of science ; but all who know section, or “groupe as he terms it, thereof. The synohis work will cordially re-echo the words of the Governor- nymy and the bibliography are not repeated, and so each General in Council-that the Meteorological Department work remains incomplete without the other, and double of India "lost in him an officer whose industry, talent, reference is entailed-a process which is always vexaand technical knowledge it will be hard to replace.” tious.

H. F. B. Unfortunately, too, the subject is conceived exclusively

from a shelly point of view ; indeed, the fact that the

shells ever had an animal origin and connection, is most FRENCH MALACOLOGY.

skilfully concealed in the body of the work, and the

'nasty creature' is only alluded to when, in the introLes Coquilles marines des Côtes de France; description duction, it becomes necessary to refer to its habitat, or

des familles, genres, et espèces. Par A. Locard. Pp. 384 ; to describe the method of its elimination prior to the 348 Figures in Text. (Paris : Baillière, 1892 [or rather deposition of the all-precious tenement in the cabinet. 1891].) Also issued as tom. xxxvii

. (1891) of the To such a point is this persistent ignoring of the animal Annales de la Société Linnéenne de Lyon.

carried, that, in defining the topography of a bivalve MORE favourably situated than these isolated and shell

, the customary and intelligible terms "right" and

the arbitrary Molluscan fauna which numerically is richer far than designations of “upper” and “under,” a nomenclature ours; whilst her political boundaries embrace portions of derived from their position when the shell is placed on two terrestrial regions and two marine Molluscan pro- its side upon the table with the umbones pointing towards vinces.

the left.

The result is that, whilst in the majority of instances not always unexceptionable, as witness Murex Brandarithe upper is equivalent to the left valve, in Nucula, which formis. is opisthogyre, the author has 'got the head where the If we comment thus strongly and at unmerited length tail should be,' and writes, for example, of N. sulcata upon this production, it is not because we mean to imply (pp. 329-30): “région antérieure presque droite, très the work is altogether without merit, nor because we étroite; région postérieure très developpée, oblique." It fail to recognize the honesty of the attempt. It doubtless is only fair to add that in Donax, thanks to the pre- to a certain extent supplies a want, and helps to fill a sence of the well-marked external ligament, this error is void : it is well printed and on good paper, with a good avoided.

index, and some of the little illustrations are excellent. The author's recognition in his introduction that every The subject, however, is a worthy one, and deserving species is liable to variation, and his wise resolve not to of broader, and, we regret to have to say it, more cumber his book with trashy“ varieties,” founded merely scientific treatment. This work, like Paetel's “ Catalog" on differences of colour or size, that have of late been so is a mere shell-collectors' book. What every student of fashionable in certain quarters, is satisfactory ; but it is the subject must desire to see is a really good treatise, greatly to be regretted that the process of elimination was worthy of the best traditions of French scientific work, not carried a step further. A very slight acquaintance and of the land of the illustrious Lamarck; one which with the animals, or even a cursory inspection of a fairly shall do for systematic French malacology as a whole extensive series of examples of the shells of the individual what Moquin-Tandon did for the terrestrial portion as species, would have been sufficient to convince any un- known to him ; and one that shall be done with the same prejudiced person that a very large percentage indeed of conscientious care which distinguished that eminent the “species” cited in this volume are but mere varieties, naturalist, and which is characteristic of the work of and unworthy of specific rank; at the same time we con- Lacaze-Duthiers, himself one of the last of a long line of fess to some fear that all argument and instance would those distinguished biologists whom France has produced, be lost on one who but lately has sought to divide so and of whom she is so justly proud.

(BV) homogeneous a species as Helix rufescens into six ! The principle adopted seems, in fact, to be, judging from

MAN'S PLACE IN NATURE. numerous instances in the pages before us, to raise

Nature and Man in North America. By N. S. Shaler. species into “groupes," and varieties into“ species ” (save

Pp. 290. (London : Smith, Elder, and Co., 1892.) the mark !). This is certainly the case in the genera Nassa, Purpura, Mytilus, &c.

PROF.

ROF. N. S. SHALER, in the introduction to his It is little wonder under these circumstances, then, that

new volume, gives a sketch of the plan of the work, M. Locard's three volumes should represent the French

and as there seems to be some want of connection Molluscan fauna as including close upon 1500 marine and between the different chapters, we prefer to quote the 1250 odd non-marine “species”! This may all be very

author's own words as to the object he has in view. He magnificent; but it is not science !

writes (p. vi.) : The systematist will also have much cause to complain

“ It seems to me to be the duty of every naturalist, of the classification adopted, which is certainly not in particularly when he has adopted the tasks of the teacher, accord with the latest views of the biologist. The extreme of a just confidence as to the relations of man to the

to use each fit occasion to show wherein he finds proof stickler for priority in nomenclature, of whom we have creative power which works in Nature. By so doing, he may lately heard a good deal, will exclaim loudly against many hope to help himself and his fellow-students to escape of the names, though, since full reference to the authority from the perplexity which has been brought about through is given in each case, there is perhaps not quite so much

the revolution in the opinions of men which modern to find fault with, although the references are not always devote the first four chapters of this book to a general

science has induced. With this end in view, I shall accurate.

statement concerning the effect of critical conditions of On the other hand, we feel convinced that no one will the earth on the development of organic life in general. approve certain arbitrary changes in the nomenclature, It will be my aim to show that geographic changes and first proposed without comment or explanation in foot the consequent revolutions of the climate which our earth notes in the “Prodrome ... Mollusques marins" (1886), has undergone, though rude and in a way destructive, but here introduced into the text itself. M. Locard appears organic creatures by the whips of necessity upward and

have nevertheless served the best uses of life, driving to entertain special objection to the use of a substantive onward toward the higher planes of being. as a specific name, and converts it into an adjectival form, “ I shall give the latter half of this essay to the disat the same time retaining the name of the original author cussion of geographic influences upon man, endeavoring as its sponsor! For example, Purpura lapillus appears to show, at least in a general way, how the development as P. lapillina ; Nassa granum is changed to N. grani- of race peculiarities has been in large part due to the

conditions of the stage on which the different peoples formis; Murex nux into M. nucalis; Aporrhais have played their parts. I shall endeavor to trace in pespelicani masquerades as A. pelecanipes; Pholas outline the effect of the geographic conditions on the dactylus is turned into P. dactylina. We also find development of peoples in the past, and to make a someCassis Saburon altered to C, Saburoni ; and Murex what careful study of these problems as they are exhibited scalaroides to M. scalariformis.

in North America." It would be interesting to learn on what principle, if Less than half of Prof. Shaler's book is devoted to any, these alterations are made, since some names that Nature and man in America, but this part is decidedly the might apparently be equally objected to are left (fortu- best, and shows more signs of care than the earlier nately) untouched ; whilst M. Locard's own names are chapters. For these reasons, and because the title of the

volume shows that the last hundred pages include the more The author apparently does not observe that if the important part, we will first deal with chapters v. to viii. trade-winds are the main cause of the equatorial current,

Beginning with a sketch of the dependence of man on it is probable that the persistent south-westerly winds of his environment, the author proceeds to an account of the the North Atlantic may also have much to do with the effect of environment on the development of various races. ocean current which follows the same course. To the English reader one of the most interesting parts In chapter ii., Prof. Shaler speaks of the nature and of chapter v. will be the account of the effect of the origin of continents, development of life, mountain isolation and other physical peculiarities of Britain on growth, saltness of the sea, &c. ; and in chapter iii., of the development of the English race.

the permanence of continents, including a sketch of the In chapter vi. the author more especially deals with the position of the shore lines from pre-Cambrian times to the dependence of the native races of North America on geo- Glacial epoch. Chapter iv. deals with a great variety of graphical and climatic conditions. This section leads by subjects, such as the condition of the faunæ and flora in a natural transition to the competition between the white Cambrian time, Croll's theory of the origin of coalcolonists and the Indians, and to the effect of barriers measures, conditions of continental growth in Europe, and strongholds in retarding or helping the gradual uniformity in past time of the composition of the atmospread of the white races in North America.

sphere, and variations in the Gulf Stream. Chapter vii. deals mainly with the relation of man to Prof. Shaler, in his first four chapters, deals so largely soils and climate, with the introduction of the negro race, with questions relating to the geographical distribution and with the extent to which the negro and the white of animals and plants, that it surprises us to find a good races are likely to compete.

many statements which more care in revision would In chapter viii., Prof. Shaler turns to the sparsely in certainly not have allowed to pass. Thus, speaking of habited regions west of the Mississippi, and here he local forms that must be developed through the longtreats mainly of the capabilities for settlement of tracts continued competition of different assemblages brought still untried by white men. He speaks of the climatic into close proximity in a mountainous district, the author conditions, of the probable value of the soils, of the re- remarks (p. 27) that:clamation of the arid regions by irrigation, and of the “In a continent such as Europe, where a great diversity probable fitness of the Western States for permanent in the mountain systems favours the localization of life settlement by men of Aryan race : he concludes that this and the development of peculiar forms, the tendency is part of America is capable of sustaining an enormous

to develop in separate mountain strongholds particular population, and that white men can thrive in most parts

species, and evolve their militant peculiarities until the

forms are fitted to enter into a larger contention with of it.

their kindred species in less localized assemblages of To those who have not read Prof. Shaler's articles in life.” Scribner's Magazine, we can recommend the last four

The example is most unfortunately chosen, for of all chapters of his book as giving an interesting and readable

the continents Europe least illustrates the process ; one account of man's relation to Nature in North America.

would have thought that no naturalist would have brought The first four chapters we cannot praise : they seem to

forward the Europe of the present day as a good illusbe largely made up of miscellaneous notes hastily put

tration of the differentiation of species on mountains and together with little arrangement and without careful re

in isolated valleys. Our Alpine flora and fauna, instead vision; they swell the bulk of the volume, but bear only

of varying greatly on the different chains, are more remotely on the relation between Nature and man in North

remarkable for their uniformity over all the continent. America.

Our valleys seldom, if ever, contain plants and animals Chapter i. treats inainly of the zoological and botanical of local origin, for the Glacial epoch is of too recent a provinces of the present day, and their dependence on physical barriers and on climate. These pages are full of affected Europe too seriously to allow many pre-glacial

date for many local forms to be developed, and has interspersed suggestions as to what might have been if forms to survive in their original limited stations. Had conditions had been different, but some of these sugges

Prof. Shaler pointed to the mountains of sub-tropical tions do not seem to have been carefully thought out, and

and tropical America, with their local species of hummingsometimes the author adopts irreconcilable views in

birds, we should not have objected. We have marked other parts of the same volume. We find, for instance,

many other equally questionable statements, which it numerous speculations as to the effect that would be produced by the diversion of the Gulf Stream, and, among

is surprising to find made on the authority of Prof.

Shaler. others, the following passage, in which, after speaking of

The occurrence of various statements of doubtful the lowering of the initial velocity that would follow from

accuracy, the debatable character of much of the a submergence of the peninsula of Florida, the author

evidence, and the complicated nature of the questions observes (p. 21) :

dealt with, make us hesitate to endorse the author's "It is mainly, if not altogether, to this initial velocity opinion that this book “is particularly designed for that we owe the efficiency of the Gulf Stream as a warmth- the use of beginners in the study of geology.” Specubringing current in high latitudes.”

lations as to what might have been if conditions had But on p. 129 we read :

been different are scarcely suitable for the beginner in " It is a well-known fact that our oceanic streams are, any branch of natural science. The skilled naturalist or in the main at least, a consequent of the movement which geologist, able to discriminate, may obtain useful hints the air has in the trade-winds of the tropical district.” from the present volume.

C. R.

mant

OUR BOOK SHELF.

Theory of Heat. By J. Clerk Maxwell. Tenth Edition.

With Corrections and Additions by Lord Rayleigh. Stones for Building and Decoration. By George P. (London: Longmans, Green, and Co., 1891.)

Merrill, Curator of Geology in the United States
National Museum. (New York: John Wiley and

This book is so well known, and has been of such good

service to students, that it is scarcely necessary to do Sons, 1891.)

more than note the fact that a tenth edition of it has This work deals almost exclusively with the building and been issued. Only such corrections and additions have ornamental stones of the North American continent, the been introduced as seemed, in Lord Rayleigh's judgreferences to similar rocks in Europe and elsewhere being ment, to be really called for. They are in great measure usually meagre and sometimes disappointing. As an derived from Clerk Maxwell's later writings. account of the rocks of the United States which are of economic importance as building materials, the work is, however, a very admirable one; and, as might have been expected in a treatise bearing the name of so well-known an authority as Mr. Merrill , the book is replete with

LETTERS TO THE EDITOR. valuable information both to the geologist and the [The Editor does not hold himself responsible for opinions exarchitect.

pressed by his correspondents. Neither can he undertake Mr. Merrill gives, in the introduction to his work, an to return, or to correspond with the writers of, rejected interesting sketch of the gradual substitution of stone for rnuscripts intended for this or any other part of NATURE. wood as a building material among the early settlers in No notice is taken of anonymous communications.] New England, and then proceeds to sketch the distribution of the different varieties of building stones in the

The Implications of Science. several States and Territories of the Union. The chapters PERMIT me, through your columns, to thank Mr. E. T. Dixon which follow, on the minerals of building stones, and on for his letter, which appeared in NATURE of December 10, the physical and chemical characters of the rocks which 1891, p. 125, concerning my lecture on the implications of are employed in construction, are very admirably written ; seience, and, very briefly, to reply to it. the illustrations of the microscopical structure of building He is very much mistaken in thinking that I place our knowstones, and the remarks on the nature and causes of dis- ledge of the law of contradiction" and of "our own conintegration in different varieties, being alike excellent.

tinuous existence” in the same category. I regard them as In classifying building materials, Mr. Merrill very wisely principle, the latter a particular fact. Since Mr. Dixon merely

truths fundamentally distinct. The former is an abstract adopts a combination of practical and scientific methods. affirms without arguing, he must permit me to contradict him, Among the crystalline and vitreous rocks, he distinguishes, and say that the law of contradiction is a necessary and objective in the first place, those which are simple or made up of truth-one that does not merely express a “verbal convention," one mineral only-namely, steatite and soapstone, serpen- and is not of the nature of a definition.". It is so objective tine (including the verdantique marbles), gypsum (in- that Omnipotence itself could not violate it-could not, e.g., cluding alabaster and satin spar), and limestones with cause a creature to have at the same time both four and only dolomites. In dealing with the compound rocks, or those Three legs. But “our continuous existence" is so far from built up of several different minerals, Mr. Merrill adopts being a necessary truth that, if an Omnipotent Creator exists, the usual petrographical distinction of massive and there can be no impossibility in our annihilation. That we canschistose (or foliated) rocks. The former he divides into

not be annihilated while we know we are actually existing is, of the four groups of rocks containing free quartz, rocks

course, true ; but that fact, so far from serving Mr. Dixon's without quartz, but containing orthoclase felspar, rocks

argument, is but an example of the validity of the law of contrawith plagioclase felspar, and rocks without felspar. existing” and “absolutely annihilated.” My critic seems to be

diction. We cannot at the same time be both “consciously The fragmental rocks are divided into the psammites still in bondage to that subjectivism and nominalism wherein I (sandstones, &c.), the pelites (clays, &c.), the volcanic was so long involved, and whence I only extricated myself tuffs, and the rocks built up by organisms.

slowly and with much trouble. The chapters on the methods of quarrying, working, As to memory, I said that we may, as everybody knows, and testing building stones are especially admirable, and make mistakes, but that nevertheless we are as certain concernthe illustrations of the great quarries of the United States, ing some parts of the past as of the present. Most assuredly I reproduced from photographs, are of great interest. The am quite as certain that I read Mr. Dixon's letter as that I am remarks on the processes which have been devised for

now in the act of replying to it. Our confidence in our memory the protection and preservation of building stones, and

cannot depend upon induction, because, if we had it not at the tables giving the crushing strength, specific gravity, starting, we could make no induction or enumeration whatever.

My "implications of science” are truths, and not "purely ratio of absorption, and chemical composition of all the

verbal assertions,” but I never affirmed any “peculiar certainty chief varieties of building stone employed in the United

for “ mathematical conclusions.” Helmholtz has never shown, States, cannot fail to be of great value to practical men.

to my knowledge, that two straight lines could ever inclose a space. It would be hard to find a more admirable example of Of course, if his supposed dwellers on a sphere" chose, as the value of exact scientific knowledge when applied to Mr. Dixon says, to apply that term to what are not straight the treatment of economic questions than is afforded by lines, different conclusions would follow. No one denies that the work before us.

two curved lines can be conceived of as inclosing a space. Les Champignons. Par A. Acloque. (Paris : J. B. Bail

Similarly, if Mr. Dixon's inhabitants of the Dog Star chose, as

he again says, “to define four as I + I + 1," then for them lière et Fils, 1892.)

two and two would not be four. But who was ever so absurd The author of this book has found much to interest him in as to suppose they would be? If any persons choose to give to the study of his subject, and he communicates in a clear, the term "an angle” the signification we express by the words pleasant style the leading facts and laws which have been a mutton chop," then certainly our conception of a triangle brought to light by mycologists. Having presented in

would not apply; for three such angles would not be equal to an introductory chapter some general considerations, two

right angles.

Mr. Dixon is good enough to instruct us that “the law of con. he proceeds to deal with the subject from the anatomical, the physiological, and the economical points what man out of Bedlam woukl suppose that a statement of an

tradiction never tells us whether anything is or is not.” But of view. Finally he gives a summary of mycological abstract general law would inform us about a particular concrete taxonomy. Thé book belongs to the “ Bibliothèque thing? On the other hand, the law of contradiction does not Scientifique Contemporaine,” and is in every way worthy tell us, and never by any possibility could tell us, “ that the terms of a place among the other volumes of the series. ‘is' and “is not’ are not applicable to the same thing"—though

is Touteren Methodison goes on to say that

, “ if the inhabitants

by applying that abstract universal and necessary law to such interdependence. And here we see why it is that, in the case things as "* terms,” we see that a term applicable to anything of mathematical inductions, we do not need to use Mill's cannot at the same time be the very opposite.

Inductive Methods.'' Mr. Dixon says : “If anyone chooses to say a thing both ‘is' and is not,' there is no law against his doing so, only if he does of the Dog Star defined 'twice,' two,' and 'four' as we do, so he is not talking the Queen's English." But by so doing he then 'twice iwo 'would be to them .four'; but to say that it breaks the law of reason, if not the law of the land ; and, was so could only give verbal information,” he may be refuted indeed, to act on such a principle when on oath in a court of out of his own mouth. For he goes on to remark that, “if the law might, after all, have inconvenient consequences.

people in the Dog Star chose to define sour as I +1+1, the soMy critic is obliging enough to say in plain and simple terms : called 'necessary truth' would not even be true!"; thus showing "Dr. Mivart is wrong in speaking of the objective absolute validity clearly that it is the facts signified, and not the words which of the law of contradiction.” To this I might content myself by signify them, that we are concerned with. According to Mr. replying : “ Quod gratis asseritur gratis negatur! But let us Dixon, it would be (for me) a necessary truth that I have a headavoid the use of the terms “is" and “is not": they are not ache, or am writing with a lead-pencil ; while mathematical necessary for my purpose. Does Mr. Dixon really doubt truths, in as far as "real,” are obtained by induction, and are whether, if he had lost one eye, he would still remain, after therefore not necessary. I hold, on the contrary, that mathe. that loss, in the very same condition he was in before? If any matical truths, though obtained by induction, are necessary one does not see the objective impossibility of such a thing that is, true under all circumstances—and that it is only by a everywhere and everywhen-ie. if he does not apprehend the confusion between " necessary” and “certain " that a statement application of the law of contradiction—then he either does not of the apprehension of present fact can be called a “necessary understand the question, or his mental condition is pathological. truth."

E. E. C. JONES. The implications of science are implied. Men may pretend to Cambridge, December 14, 1891. doubt them, their own existence, or the objectivity of mathematical truths. But their practice shows their unsailing con. fidence in them on each occasion as it arises—as when cheated Supernumerary Rainbows observed in the Orkneys. by false accounts, personally injured, or engaged in scientific I INCLOSE a letter just received. The writer has charge of research. When we enter the laboratory, we leave these follies the anemometer formerly kept by the late Dr. Clouston. Dr. outside.

ST. GEORGE MIVART. Clouston first crew my attention to the extraordinary bow seen Hurstcote, December 22, 1891.

at Kirkwall in 1871. My note is in the Quarterly Journal of

the Meteorological Society, vol. i. p. 237. Will you allow me to say a few words in reference to four

Robert H. SCOTT, points in Mr. E. T. Dixon's indictment (NATURE, December 10, Meteorological Office, 63 Victoria Street, S.W., p. 125) of Mr. St. George Mivart?

December 31, 1891. (1) Mr. Dixon asserts that the law of contradiction “is not a

Deerness Public School, Kirkwall, December 28, 1891. necessary truth at all, it only expresses a verbal convention

SIR, -On reading your very interesting work on "Elementary it "never tells us whether anything 'is' or 'is not.' It only Meteorology," I find, on p. 201, reference made to "an extrainforms us that the terms 'is' and is not ’are not applicable ordinary bow" which appeared at Kirkwall, November 13, to the same thing." But though it may be only a “verbal con

1871, which you explain by the reflection of the sun's rays from vention" that in “the Queen's English" not is the sign of

a water surface. negation, it is not a mere verbal convention that if a signifies

On Saturday, the 26th inst., at 3.20, when the sun was on the the negation of A (whatever A may stand for), then A and a

horizon, I saw a very distinct rainbow; there was no trace what" are not applicable to the same thing”-as the law of contra

ever of the secondary bow, but between where it ought to have diction asserts, and as Mr. Dixon himself allows. A highly been and the primary one there were several patches of what are abstract law that is concerned with the relations of propositions called “supernumerary” bows. The only colour I saw distinctly cannot, of course, tell us whether any particular thing exists or

was the red. not--but then no one has ever expected that it should; and This lasted for about four minutes, when, finally, a second moreover, assertions (or denials) of the “existence” of particular bow appeared just inside the primary, with the colours arranged objects are not the only “real” propositions (Mr. Dixon

as in the primary-not reversed, as the secondary. The space appears to be misled here partly by the ambiguity of is).

between the violet of the primary and this one was almost nil. (2) Mr. Dixon says that the law of gravitation-like other The red next the violet of the primary was about as distinct as laws suggested by particular experiences-depends ultimately that of the primary. The orange and yellow were distinct also, upon induction per enumerationen simplicem ; that is, upon an but the others could hardly be seen. This was, no doubt, owing inference of the form This A is X, that A is X, &c. (= Some to the fading light of day, and to the dark colour of the clouds d's are X), :. All A's are X (for we can make nothing better in the north-east, where the bows appeared. These lasted disout of an induction by simple enumeration). But this inference tinctly and complete for about one minute. The bows formed, is merely an immediate inference, and moreover an illegitimate as is well known, half a circle. The sun was setting behind land ode; hence, according to Mr. Dixon's view, inductions have no at the time, and the wind was blowing at the rate of forty-five logical justification whatever.

miles, so that there could be no water reflection. (3) Further, Mr. Dixon asserts that “the supposed peculiar If I am not troubling you too much, would you kindly say if certainty of mathematical conclusions is solely due to the fact this is unusual, and if caused by the "interserence” of rays ? that they are truisms," or "purely verbal assertions,”—by which

Yours respectsully, I understand him to mean definitions. In answer to this I should maintain that the peculiar certainty of mathematical

(Signed) M. SPENCE. propositions, and the fact that here, by help of a single instance, we unhesitatingly conclude to the universal, are (as I have

Aurora Borealis. observed elsewhere) explicable by “the consideration that we A FINE display of aurora was observed here on the evenhere see at once the connection, which in other cases we believe ing of January 4. A faint northern glow was seen at 8.30, on grounds very different from a perception of self-evident inter- which quickly grew in brightness, and at 8.45, streamers in dependence of attributes. When the equality of the interior great quantity were visible. At 9 these became tinted with angles of any one triangle to two right angles has been demon. glowing red on their upper (portions. After exhibiting lively strated to us, we infer without a moment's doubt that the same motions for a quarter of an hour or so, the phenomenon settled relation of equality may be asserted of the interior angles of down into a brilliant and steady arch of lighi, red on the outside wery triangle ; and this because we have seen that with the and white within, resting on what appeared to be a bank of attributes signified by the interior angles of a triangle' there dark cloud. By eye estimate this arch would extend about 90 is bound up the attribute of being equal to two right angles.' along the horizon, its apex over the north-north-west from We believe that, if a certain amount of arsenic has on some occa- 25° to 30° in height. The glow was still visible at 10 p.m., sions produced death, it will always produce death, on the though considerably diminished in intensity. During the whole ground that the apparent likenesses are connected with un- of the day a dry and frosty north-west wind prevailed, and the apparent likenesses; but we have not seen in this case (as we temperature at 10 p.m. was 28”.

J. LOVEL have in the case of the triangle) that there is a self-evident Driffield, East Yorkshire, January 5.

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