MM. Richard Frères, and an autographic hair-hygrometer. The section on cloud observation has been recast in accordance with the classification proposed by MM. Hildebrandsson and Abercromby, and, under the heading of "Phénomènes Optiques," halos and the aurora borealis are described. The more common appearance of lunar and solar coronas, though mentioned, is not specially noticed in this section. In a book intended for the instruction of beginners, we think it would have been well to point out the distinction of coronas and halos, since, in our experience, the latter are not infrequently recorded by inexperienced observers, when the former have been the phenomena really observed. forward; and, in consequence, the writer of "Colour Blindness and Colour Perception " regrets that he has to condemn his test. Probably the test will survive the condemnation. Already, according to the figures of Dr. Joy Jeffries, of Boston, some 180,000 persons have by its means been tested expeditiously and effectively. The mention of the American authority on the subject emphasizes the fact that the name of one whose labours in physiology and optics place him in the front rank of English physicists is omitted from the list of English authorities on the subject. Brewster, Herschel, Tyndall, Maxwell, Pole, Abney, Rayleigh, Galton, Nettleship, Bickerton, Frost, and Hogg are recognized as having added to our "knowledge of colour blindness and the dangers arising from the defect." The name of Dr. Brudenell Carter does not appear in the list! The omission is so glaring when the well-known character of Dr. Carter's contributions to the lore of colour blindness is considered, that there must be some reason for it. Doubtless it is because Dr. Carter has been guilty of the heinous crime of championing the theories of Young and Helmholtz that Mr. Green refuses to recognize him as a contributor to our knowledge of the subject under discussion. Dr. Carter once said, in the course of one of the Cantor Lectures: "I read somewhere, and have vainly endeavoured to find again, a denunciation of the 'fallacies of the Young-Helmholtz theory.'" We recommend "Colour Blindness and Colour Perception" to his attention. The so-called fallacies he will there find completely exposed and shattered in a manner most refreshing, and perfectly satisfactory--at least to simpler form represented on p. 35 seems quite inadequate Mr. Green. Careful study of Mr. Green's work forces upon one the conclusion that the theories of Young and Helmholtz are "fallacies" for the simple reason that he has failed to understand them aright. Holmgren's tests are no tests because their principle is opposed to the unscientific elaborations of Mr. Green, An extension of the field of research, together with an honest attempt to understand the "fallacies" of Young and Helmholtz, will, we are certain, induce Mr. Green to remove from his book many of its errors and absurdities. A METEOROLOGICAL GUIDE-BOOK. Instructions Météorologiques. Par A. Angot. Troisième THE HE "Instructions Météorologiques," which is the official guide-book for meteorological observers in France, has long been known as a model work of its kind, distinguished by great clearness and sufficiency of detail, while avoiding prolixity. The third edition, lately published, has been revised and extended by M. Angot, whose name is a sufficient guarantee that it maintains the high standard of the original work. The subject-matter of the present edition has been increased by nearly one-half. One of the chief additions is the description of some of the simpler self-recording instruments, which, it is stated, are coming into general use at the minor French observatories-viz. the sunshine recorder, the recording aneroid, an autographic thermometer on the Bourdon principle constructed by Another subject, treated of for the first time in this edition, is the computation of elevations from the barometric readings, and also from those of the hypsometrical thermometer, the use of which is described at length. In the appendix are given tables for facilitating the reduction of the observations of both classes of instruments. The patterns of the various instruments, thermometershelters, &c., approved by the author of the "Instructions," differ in many respects from those generally preferred by English observers, and in such matters there will, of course, be differences of opinion. The French thermometer-screen, represented on pp. 32 and 33, affords, in our opinion, a better exposure than the Stevenson screen adopted by the Meteorological Societies of England and Scotland, but seems hardly to protect the instruments sufficiently in stormy weather; while the in the latter respect, and the method of suspending the maximum and minimum thermometers somewhat flimsy and insecure. In the text of the work we find little or nothing to which we could take exception, but we think one or two of the figures are open to improvement. The close proximity of the wet and dry bulb thermometers represented in Fig. 16 is hardly compatible with accurate registration of the humidity of the air; and surely the wind-vane represented on p. 73, on the slope of a roof at some indefinite distance below the ridge, is scarcely in an ideally good position, and such as should be put before learners as a standard model for imitation. We would also suggest that, in future editions, a simple form of nephescope, such as Marié Davy's, should be described, together with directions for observing the movement of the clouds. It has long been a matter of surprise that a class of observations so important in themselves and so easily made has been so generally ignored by the writers of such manuals as the present. OUR BOOK SHELF. Chambers's Encyclopædia. New Edition, Vol. VIII. (London and Edinburgh: W. and R. Chambers, 1891.) WE are glad to welcome a fresh instalment of this admirable edition of Chambers's well-known Encyclo pædia. It deals with the subjects indicated by jects of scientific interest have, as usual, been intrusted words extending from "Peasant" to "Roumelia." Sub to writers who know how to present concisely and clearly the latest results of research. A clear account of the phonograph is given by Mr. Thomas A. Edison; and Mr. T. C. Hepworth and Mr. W. T. Bashford trace the history and describe carefully the various processes of photography. Mr. J. S. Keltie has an excellent article on Polar exploration, illustrated with a North Polar and a South Polar chart. A short but very good paper on protoplasm is contributed by Mr. J. A. Thomson; and Prof. Sorley makes the most of the few pages set apart for psychology. Rain is discussed admirably by Dr. Buchan, and the rainbow by Mr. W. T. Omond. Reflection and refraction are dealt with by Dr. Alfred Daniell. The main facts relating to the Red Sea are presented by Dr. John Murray; and Dr. Hugh R. Mill sets down all that is likely to be wanted by students who have occasion to refer to the article "River." Altogether, the various papers we have examined may be commended as in every way worthy of the high reputation secured for the present edition by preceding volumes. .La Place de l'Homme dans la Nature. By T. H. Huxley. (Paris: B. B. Baillière et Fils, 1891.) 66 MORE than twenty years ago a French translation of Prof. Huxley's well-known work, Man's Place in Nature," was published. The translator was Dr. E. Dally. In the present volume this rendering is reissued, and along with it are associated translations of three papers in which Prof. Huxley has presented his ideas on various ethnological subjects. These papers have been translated by Dr. Henry de Varigny, to whom Prof. Huxley expresses thanks for the care he has taken to represent clearly and faithfully the meaning of the original. The volume will be very welcome to French students who desire to understand the methods and tendencies of English scientific thought. LETTERS TO THE EDITOR. [The Editor does not hold himself responsible for opinions expressed by his correspondents. Neither can he undertake to return, or to correspond with the writers of, rejected manuscripts intended for this or any other part of NATURE. No notice is taken of anonymous communications.] Smithsonian Standards for Physical Apparatus. On the occasion of a scientific expedition of which I had charge many years ago, the need of common standards of size for the parts of different astronomical and physical instruments was brought forcibly to mind; for the instruments used, while of the latest and best construction, were necessarily dismembered, and then transported in fragments to their scarcely accessible destination by numerous independent bearers; and if any accident happened to any fragment of any piece of apparatus, it was found, as a rule, that the whole was rendered useless, since it could not be replaced from the like parts of other pieces which were spared. The weapons of attack of the little scientific force were, then, in one important respect, far inferior to those of modern warfare, in that there had been no attempt to make their parts interchangeable. My attention having been drawn to the matter, I was led to examine astronomical and physical instruments in all cabinets accessible to me, with a special view to this feature. I found that, as a rule, no draw-tube, screw, or other piece from one instrument would fit the corresponding parts in any other, there being no attempt to make them interchangeable even where they came from the same maker. This experience must be confirmed by that of most others, who will probably agree that this is a cause of incessant, but quite avoidable, loss and delay, even where apparatus is used under ordinary conditions, and it has led to inquiry for some scheme which would assimilate different parts of the work, not only of the same, but of different makers. Some of the plans suggested are well matured, and in themselves apparently commendable, but all are too complex, the ambition of the authors being, as a rule, to make them so complete as to cover all possible demands of future progress. What has been wanted by many others doubtless is some simple and practicable plan for immediate use, which shall yet be found in accord with the larger scheme which may be under consideration hereafter. When it fell to me to meet the somewhat varied wants of the Smithsonian Institution by a plan which should at least enable a beginning to be made in the right direction, it seemed that this should be with such simple and general conditions, that common consent to them might almost be counted on, at least on the part of all ready to use the metrical standards. To provide for the immediate practical wants of this Institution, advice was sought of several of the best instrument makers, and a considerable number of tubes and screws by English, French, and German, as well as American makers were examined to find out the sizes which long-established use in these countries had shown to be practically convenient, and the forms of screws which the best modern practice of scientific instrument makers concurred in; and this having been done, dimensions having a metrical unit, and as near these sizes as practicable, were adopted-not as a finality, but as a beginning. In the hope that others may consider this very modest attempt to be in the right direction, and that these standards may fall into use for immediate needs, and thus tend to bring about the adoption of that much more complete system of international standards which most will admit to be (at least in the abstract) desirable, I beg leave to inclose a circular which has been sent to all instrument makers employed by this Institution. trusting that you may find it of sufficient interest to bring it to the attention of the readers of NATURE. S. P. LANGLEY, Secretary. Smithsonian Institution, Washington, D. C., December 16. Circular to Instrument Makers. When any new tube has to be ordered, it should be made one of these diameters and chased with one of these threads, if this can in any way be done. New eye-pieces are to be as far as possible made to fit the three-centimetre plug gauge supplied by Pratt and Whitney, and in fitting them to old work, this size is still to be adapted wherever possible. The Institution is preparing standard plugs and gauges of the diameters given above, and has on hand chases of 5, 7, 10, and 15 threads to the centimetre. All screws have the 60 thread, with flattened top and bottom. These it will supply at first cost to any instrument maker engaged in its work. Plug gauges are to be had of great accuracy and at moderate cost from several standard tool makers. Those here referred to have been made for the Smithsonian Institution by the Pratt and Whitney Company of Hartford, Connecticut, and are within a limit of error of two-hundred-thousandths of an inch at 62° Fahrenheit. The hobs are from the same makers. Pigment in Yellow Butterflies. Apropos of the interesting discussion on comparative palatability and warning colours (NATURE, November 19, p. 53; November 26, p. 78), it may be of interest to your readers it I restate in your columns some of the properties of the yellow pigment contained in the wings of the common brimstone and many other butterflies; the possible significance of which in conferring protective unpalatability is suggested by Mr. Beddard. My paper on the subject, to which Mr. Beddard refers, was read before the Chemical Society in June 1889; but, being more or less of a preliminary nature, it was published only in the abstracts of that Society's proceedings (Abst. Proc. Chem. Soc., vol. v., 1889, p. 117; vide also NATURE, vol. xl. p. 335). Its The pigment is freely soluble in hot water, though quite insoluble in cold water, and in most organic solvents. aqueous solution is strongly acid to litmus; and, though it appears to be quite innocuous to frogs when injected under the skin, it may well be ungrateful to the ranine palate. At the same time it must be noted in this regard that its solubility in the secretions of the frog's mouth is but very slight. The substance is, as I have shown, undoubtedly a derivative of uric acid, yielding the latter body as one of its products of hydrolysis. It gives the murexide reaction direct. It forms quite definite salts with metals, its compounds with the alkalies being soluble bodies. throw the smallest degree of light upon the above question. There is always, he adds, the "object" which runs through the whole of organized nature; which cannot be accounted for by means of the known properties of physical forces. In concluding his paper he says:-"If one plant or animal differs from another, or the parent from the child [and, we may add, the scion from the stock], it is because in the building up process the determinations of molecular motion were different in the two cases; and the true and fundamental ground of the difference must be sought for in the cause of the determination of molecular motion. Here, in this region, the doctrine of natural selection and the struggle for existence can afford no more light on the matter than the fortuitous concourse of atoms and the atomical with the following remark of Sir J. D. Hooker on the origin of secretory glands of Nepenthes :-"The subsequent differentiation of the secretory organs of the pitcher into aqueous, saccharine, and acid would follow pari passu with the evolution of the pitcher itself, according to those mysterious laws which result in the correlation of organs and functions throughout the kingdoms of Nature; which, in my apprehension, transcend in wonder and interest those of evolution and the origin of species." 1 Having regard to the wide spread presence of the body in the scales of diurnal Lepidoptera, I have ventured to call it lepi-philosophy of the ancients." This observation seems to agree dotic acid. In its physical properties it closely resembles mycomelic acid, a yellow derivative of uric acid; and, in my original paper, I ventured to suggest a formula for the body. I hope shortly to publish a more complete account of the subject, and to assign a formula to lepidotic acid based upon fuller evidence. Meanwhile, in common with many others of your readers, I am looking forward to the appearance of Mr. Beddard's book. The literature of the subject of animal coloration is not easily accessible, and a text-book thereon will be a valuable acquisition. We have, it is true, the interesting work of Mr. Poulton; but the subject is there treated from what is, perhaps, a somewhat limited standpoint. F. GOWLAND HOPKINS. Sir Wm. Gull Research Laboratory, The Chromosphere Line à 6676°9. 66 IN response to Father Cortie's implied question as to the identification of this line as belonging to the spectrum of iron, I would refer him to Appendix G of Roscoe's lectures on Spectrum Analysis" (third edition). It is an extract from a joint paper by Ångström and Thalen, giving a list of several hundred (then) new identifications; among them appears K 654 3, ascribed to iron. The original memoir was presented to the Stockholm Academy of Sciences in February 1865, and an English translation of it appeared the next year. I am unable to assign any reason why many of the identifications given in this memoir fail to appear in the map published three years later; but they do, and K 654 3 is among the missing. C. A. YOUNG. Princeton, N.J., U.S., December 15. Grafts and Heredity. I HAD not thought of grafts when I wrote my paper, and I have to thank Mr. Beeby for reminding me of an excellent illustration of my views; though I cannot gather from his letter whether he considers the "individuality" for which he contends to be represented by matter or force. Adopting his phrase I would apply it to both. The material form, e.g., of the leaf of the scion, is due to molecular motion, set up by a group of forces acting in a way peculiar to the life of the scion ; which forces, together with the resulting form, constitute its individuality-somewhat as a man is known by his mental and moral characters as well as by his face. Now, no two individual plants could be fed more alike than a stock and its grafted scion; since they both receive identically the same food through the roots of the former. All I contend for is, therefore, that it would seem to be more probable that the organic molecules constructed out of this food are all alike, only differently arranged in the leaf of the scion and in that of the stock respectively. These arrangements must be due to molecular forces; while it is difficult to conceive in one's mind how any special kinds of matter can be concerned in the construction of the special forms of leaves; to say nothing of the total want of evidence of the existence of germ- or other plasm. There is, however, a deeper question still which Mr. Croll asked: "What determines molecular motion?" 1 He observed that although physical forces are not only interchangeable but can pass into those which, for want of a better expression, we may call vital energies; yet, as he says, nothing we know of in the properties of physical forces can "What Determines Molecular Motion?-The Fundamental Problem of Nature" (Phil. Mag., July 1872). The nearest approach to an answer to Mr. Croll's question is, as it seems to me (though it be but cutting the Gordian knot after all), that there exists a responsive and adaptive power inherent in living protoplasm which is called into action by external forces; so that by a change of environment—especially if the old and the new one be strongly contrasted-a plant, as a rule. at once begins to alter its structure so as to re-establish equilibrium with its new surroundings; and further, if these be maintained long enough, the altered structures become fixed and hereditary, while more or less of readaptation can commence again at any time. We can no more discover the ultimate cause of this power which determines or directs molecular motion in living beings, than we can that of crystallization or gravity, reflex action or instinct. Innumerable facts, however, justify the full recognition of its existence. To apply this to grafts. It is obvious that, whatever determines the molecular motion in forming the leaf of the scion, it is different from that which determines the molecular motion in forming the leaf of the stock, since the resulting forms of the leaves are different; and it is just this ultimate determining power, which is unknown and apparently unknowable, which characterizes the individuality of the scion on the one hand, and of the stock on the other. Form is but the outward and visible expression of this power. It is this, too, which underlies the responsiveness of protoplasm, and determines a new form in adaptation to, or in equilibrium with, a changed environment. Mental Arithmetic. GEORGE HENSLOW. THE very simple method of multiplying large numbers, published in NATURE (p. 78) by Mr. Clive Cuthbertson, is mentioned by Pappus, Book II. (ed. Hultsch), 2-29, as an invention of Apollonius. The same method was known to the Hindoos under the name Vajrábhyasa (Algebra with Arithmetic and Mensuration from the Sanskrit Brahmegupta and Bhascara, translated by H. Th. Colebrooke, London, 1817). The method may be enlarged to multiplying three and even more numbers all at once in the following manner : (100a1 + 10b1 + c1) (100α, + 10b + c) (ICoag + 10b3 + (3) : = Address to the Department of Zoology and Botany of the British Associa tion, Belfast, 1874. Nor are The Migration of the Lemming. HAVING resided during the summer months for more than twenty years on the plateau from which the migrations of the Norwegian lemming are supposed by many to take their origin, I can speak from personal observation. Some years ago I had the honour to read a rather lengthy paper before the Linnean Society on these animals, and, with one exception, to which reference will be presently made, I am happy in having nothing to alter or recant. The increase of the Lemmings is not cumulative, but rather periodic, as indeed is usual among the voles as well as among many other forms of life. The migrations are not caused by insufficient food now, whatever they may formerly have been, and this is evident from the fact that the swarms pass through, but do not exhaust the fertile districts which they encounter on their nilgrimage. they affected by any personal struggles between these most pugnacious of animals, for the young litters, when reared, go singly on the journey from which none have ever been observed to return. They do not follow the watershed, and they do not always migrate to the west-an error into which I was betrayed by trusting to common report and insufficient personal experience. But they do go straight. It is well known that the eyes of the lemming are so placed on the top of the head as to render it impossible for the animal when swimming, to discern any object not far above the plane of its horizon. On a calm morning last summer, I often placed my boat in the path of the swimmers, and noticed that they crossed my lake in an absolute "bee-line," and that they could not discern my presence until the angle subtended by the boat was infinitely higher than that of the opposite shore. This latter migration was south-east, and in the late autumn the steamer on Lake Mjosen made its way through thousands of these hapless wayfarers; whilst, still later, large numbers were to be seen close to Christiania; but I venture to prophesy that none will be found in that neighbourhood next year, nor, for the matter of that, in Heimdalen itself, though it is obvious that some must remain. Probably the explanation of these apparently capricious and suicidal migrations may be that they are the result of hereditary instinct, which formerly was of service if not necessary to the species. The straight course which they pursue must be owing to the sense of direction common to migrants, and I would hazard the conjecture that the changes of destination may be due to an instinct which, owing to its present inutility, is gradually diminishing in precision and intensity. W. DUPPA-CROTCH. Asgard, Richmond, December 24. The Recent Earthquake in Japan, DANS la lettre de M. J. Milne, Tokio, 7 novembre, sur le tremblement de terre du Japon du 28 octobre, 1891 (NATURE, xlv. 127), il y a entr'autres un fait intéressant: c'est la mise en oscillation de l'eau d'un bassin de 60 pieds de longueur sur 25 pieds de profondeur. Il est rare que dans un tremblement de terre l'eau des étangs ou des lacs soit mise en mouvement; le rythme des vibrations du sol ne correspond pas, le plus souvent, ON THE VIRIAL EQUATION FOR GASES AND VAPOURS. ALTHOUGH I had, some time ago, written to Lord Rayleigh to the effect that I did not intend to prolong the discussion of this question, it may perhaps be expected that I should say a few words with reference to Prof. Korteweg's paper in the last issue of NATURE. 1. I do not agree with Prof. Korteweg's statement that Van der Waals's method, if it could be worked out with absolute rigour, would give the same result as the direct method. There is but one way of dealing with the virial equation :-if we adopt it at starting we must develop its terms one by one, and independently. In this connection I may refer to Lord Rayleigh's statement (NATURE, 26/11/91): "It thus appears that, contrary to the assertion of Maxwell, pis subject to correction." I cannot admit that is " corrected"; it is not even changed either in meaning or in value. It is introduced as, and remains (at the end of any legitimate transformations of the equation) the value of the pressure on the containing vessel. This, of course, depends upon what is going on in the interior. Other terms in the virial equation, which happen to have the same factor, may be associated with p for convenience; they assist in finding its value, but they do not change its meaning, nor do they "correct" it. 2. I do not think that much aid can be obtained by analogy, at least in the present question, from the case of one-dimensional motion. For the latter may be looked on as virtually the to-and-fro motions between fixed boundaries of a number of particles, each of which keeps its speed for ever unchanged, except at the moments when two instantaneously pass through one another. From this point of view the result of Lord Rayleigh and of Prof. Korteweg follows at once. Make the particles mere points, and diminish their free range by the sum of their original lengths, and everything will go on practically as before. Can a corresponding statement be made for three dimensions? Again, there is in the onedimensional case a perfectly arbitrary set of speeds, which remains unchanged :-there is nothing analogous to the beautiful statistical distribution of Clerk-Maxwell. And what would be the result if molecular forces were introduced? 3. Prof. Korteweg seems not to have noticed the following sentence in my second letter to Lord Rayleigh (NATURE, 29/10/91, p. 628) :—“The true mode of getting a cubic here... [i.e. in Prof. Korteweg's notation, can not." I had, originally, added a sentence to the effect that, if y be taken equal to B, Van der Waals's result would at once be obtained. But I struck it out as irrelevant, because the discussion turned mainly upon the question of the value of the free path at a volume nearly equal to the critical volume. Here Van der Waals expressly recognized that his b must be diminished in value. From my point of view, ẞ (having been determined once for all) is unchangeable; while y is essentially less than B, possibly even negative. Prof. Korteweg takes a different view, and says that the "true" formula is obtained by the process above hinted at:-i.e. by putting (with the preceding notation) Y = B. 4. Prof. Korteweg speaks of the equation written above as "quite worthless." But, in all this discussion, where the rival expressions differ only by the introduction or rejection of terms of the order B/; which, according to Prof. Korteweg, make an equation "true" or "quite worthless" as the case may be are we not introducing an error, of that order at least, in calmly writing ON THE RELATION OF NATURAL SCIENCE WE The same neglect, at least of sculpture and painting, An Address delivered by E. du Bois-Reymond, M.D., F.R.S., at the annual meeting of the Royal Academy of Sciences of Berlin in commemoration of Leibnitz, on July 3, 1890. Translated by his daughter. This Address was first printed in the weekly reports (Sitzungsberichte) of the Berlin Academy, then in Dr. Rodenberg's Deutsche Rundschau, and lastly it was published as a separate pamphlet by Veit and Co., at Leipzig, 1891. strikes us in Voltaire, who as polyhistorian can in some measure compare with Leibnitz. We are obliged to descend as far as the third generation—that is, to Diderot in France, to Winckelmann and Lessing in Germanybefore we meet with a decided interest in the fine arts, and an appreciation of the part they play in the progress of civilization. The period thus defined, though it excels in science, shows with few exceptions a falling-off in the fine arts. On considering the historical development of these two branches of human productiveness, we find no correspondence whatever between their individual progress. When Greek sculpture was in its prime, science scarcely existed. True, Lionardo's gigantic personality, which combines the immortal artist with the physicist of high rank, towers at the beginning of the epoch generally known in the history of art as the Cinquecento. Still, he was too far in advance of his age in the latter capacity to be cited as an example of simultaneous development in art and science; so little that Galilei was born the day of Michael Angelo's death. The mutual development of art and science at the commencement of our century is, I believe, merely a casual coincidence; moreover the fine arts have since been at the best stationary, whereas science strides on victoriously towards a boundless future. In fact, both branches differ too widely for the services rendered to science by art, and vice versa, to be other than external. "Nature," Goethe very truly observed to reflects on part of his own scientific work-“Nature Eckermann-little thinking how harshly this remark always stern; she is always in the right, and the errors allows no trifling; she is always sincere, always serious, and mistakes are invariably ours." Fully to appreciate the truth of this, one must be in the habit of trying one's own hand at experiments and observations, while gazing in Nature's relentless countenance, and of bearing, as it were, the tremendous responsibility incurred by the statement of the seemingly most insignificant fact. For every correctly interpreted experiment means no less than this: whatever occurs under the present circumstances, would have occurred under the same conditions before an infinite negative period of time, and would still occur after an infinite positive period. Only the mathematician, whose method of research has more in common with that of the experimenter than is generally supposed, experiences the same feeling of responsibility in presence of Nature's eternally inviolable laws. Both are sworn witnesses before the tribunal of reality, striving for knowledge of the universe as it actually is, within those limits to which we are confined by the nature of our intellect. However, there is a compensation for the philosopher, labouring under this anxious pressure, in the consciousness that the slightest of his achievements will carry him one step beyond the highest reached by his greatest predecessor; that possibly it may contain the germ of vastly important theoretical revelations and practical results, as Wollaston's lines contained the germ of spectral analysis; that, at any rate, such a reward is not only in the reach of a born genius, but of any conscientious worker; and, finally, that science, by subduing Nature to the rule of the human intellect, is the chief instrument of civilization. No real civilization. would exist without it, and in its absence nothing could prevent our civilization, including art and its master-works, from crumbling away again hopelessly, as at the decline of the ancient world. This consciousness will also make up to the philosopher for the thoughtlessness of the multitude, who, while enjoying the benefits thus lavished upon them, hardly know to whom they owe them. The country rings with the name of every fashionable musical virtuoso, and cyclopædias insure its immortality. But who repeats the name of him who achieved that supreme triumph of the inventive intellect to convey through a copper wire across |