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and the mixture would also turn blue, but of only about half the depth of colour. If lichnoxanthine had been present it would have caused the colour to be green; and, after the blue product had faded, it would remain as a residual yellow. By experimenting with such known mixtures we therefore see that, independently of being able to partially separate the constituents, the evidence of the solution being a mixture consists in the difference in the position of the absorption-bands, in the change in their position, or disappearance, when partially decomposed by light, and in the relative quantity of blue substance formed by the action of hydrochloric acid, and of the residual yellow. Such, then, being the case, we know what kind of methods to employ in studying natural coloured solutions, suspected to be mixtures; and on applying them to the investigation of the solutions obtained from leaves and flowers, I find that they behave exactly like such artificial mixtures, and not only so, but there is generally no difficulty in more or less perfectly separating the constituents, so as to correspond more or less closely with the different substances in their more pure state. The evidence of their being mixtures is therefore as good as could be expected. Kraus seems never to have made such experiments, and yet he strongly criticises what I had said about the existence of several distinct kinds of xanthophyll; but I contend that by adopting the principles I have described, we can completely explain the various facts on perfectly simple principles, without supposing that the optical characters of any single substance are subject to variations from some unknown, and, as I believe, altogether imaginary

cause.

The flowers of different varieties of Eschscholtzia californica are also a good illustration of my views. The very yellow petals are coloured by yellow xanthophyll, with a very little xanthophyll and lichnoxanthine, and thus correspond with many other similar flowers, but the more orange-coloured petals, and the orange coloured portions of the yellower petals, contain in addition, another colouring matter, giving the absorption-band in the green shown in Plate II. Fig. 7, at 1 a, of Kraus's work which, however, he did not look upon as evidence of a mixture-merely of what he calls a modification. Now, on exposing such a solution in bisulphide of carbon to the sun, this orange-coloured substance is more rapidly decomposed than the others, and in a while a yellower solution is left, which gives exactly the same spectrum as that due to the colouring-matter from the yellow petals. According to this view of the subject we therefore see that the yellow flowers are of the usual type, and that the more orange-coloured portions of the petals, and the whole of the orange-coloured varieties differ only in there being developed an unusual and independent substance, which in this case is of orange-colour, whereas in the flowers of some other plants, such additional colouringmatters are red or blue, as the case may be, and instead of being allied to xanthophyll, differ in almost every particular. In conclusion I would say that the yellow colouringmatters, soluble in bisulphide of carbon, which exist in green leaves, are the above-named xanthophyll, yellow xanthophyll, and lichnoxanthine. This is probably the reason why this is also the normal type of yellow flowers, and why only in particular cases one or both of these substances are absent. To this I attribute the statement of the author that the chemical reactions are the same, for he has apparently never examined those plants which yield them in an approximately pure state.

In Pl. III. Fig. 2, Kraus gives a representation of the spectrum of a coloured solution obtained from certain species of Oscillatoriæ. This he has named phycoxanthine; but I am persuaded that the solution must have contained three perfectly distinct colouringmatters, which can be separated by chemical and photo-chemical methods, and do occur almost, or

quite, separately in other plants. For one of these substances I have adopted the author's name phycoxanthine. It may be obtained in the most pure state from the lichen Peltigera canina, when growing in such a damp and shady situation, that very little orange lichnoxanthine is developed. When dissolved in absolute alcohol and hydrochloric acid is added, it fades without turning blue. Another constituent of the mixture is what I have called fucoxanthine, which occurs quite free from phycoxanthine in Fucus and other olive Alga, and even in the same species of Oscillatoriæ, growing where there is very little light, as those which contain phycoxanthine, if growing well exposed to the sun. When dissolved in absolute alcohol and hydrochloric acid is added, it turns to a splendid blue. The third constituent of the mixed solution is what I have named orange lichnoxanthine, which can be obtained by itself from lichens, and is left when such a mixed solution as described by the author, in bisulphide of carbon, is exposed to the sun under green glass, until the phycoxanthine and fucoxanthine have been destroyed. When dissolved in absolute alcohol and treated with hydrochloric acid it fades very slowly. The relative amount of this is greatest in those specimens of Oscilla toria which grow very much exposed to the sun and air, and I have found by careful comparative quantitative analyses that the relative quantity of these various substances, which together constituted the author's phycoxanthine, varies in such a manner that, as far as the fundamental colouring-matters are concerned, the same or closely allied species of Oscillatoriæ, growing exposed to a varying amount of light, furnish a most interesting series of connecting links between olive Alga and lichens. When their vitality and constructive energy are very much reduced by want of light, their type of colouring closely approaches to that of olive Alga, whereas when they are exposed to much air and light, the type approaches to that of such lichens as Peltigera canina. I have met with other analogous cases, and if more extended research should still further confirm the existence of this analogy between the results due to abnormally reduced or increased vitality in the same kind of plants, and the normal characters of lower and higher classes of plants, it would certainly be remarkable, as showing that the vegetative energy of the lower classes is in some way or other of a lower type than that of the higher classes, and would present a striking analogy to the relation between the structure of animals whose development has been arrested, and that of those of lower organisation.

The fact of being able to prove that a coloured solution obtained from a plant is really a mixture of a number of different substances, may at first sight appear to be of very little consequence, but I trust that some of the conclusions deduced from this method of study will justify me in looking upon it as very well worthy of attention. When we come to study the various classes of plants growing under various conditions, with the view of constructing such a general science as that I have named comparative vegetable chromatology, these details become not only of the very greatest importance, but absolutely essential. By making qualitative and comparative quantitative analyses of the colouring-matters, carefully distinguishing the fundamental from the accidental, there seems every reason to believe that the petals and the foliage of plants can be brought into morphological agreement, and many of the leading classes of plants distinguished, and at the same time connected together, so as to form a continuous series, advancing from the lowest classes of animals to the highest classes of plants; whereas, if we were to look upon mixtures as independent colouring-matters, and were not to distinguish well-marked species, the whole vegetable kingdom would appear broken up and disjointed, without any chromatological continuity. H. C. SORBY

THE

OF NEW LABORATORIES THE NATURAL HISTORY MUSUEM, PARİS * IN N order to provide every facility for the higher scientific education, and induce young men to devote themselves to scientific research, the French Government have established a school of advanced study, in the form of a suite of laboratories in which young men receive a practical education par excellence; they are trained there in manipulations and dissections, and initiated in all those delicacies of touch, those turns of the wrist, which are traditional in the green-rooms (coulisses) of science, but which cannot be taught in the theatre.

Without noticing at present the zoological laboratories under the zealous management of M. A. Milne-Edwards, and through which have already passed several students desirous of taking the degree of licentiate in natural science; or the physiological laboratory, at the head of which is the eminent M. Claude Bernard, or the labora

tories of comparative anatomy and geology, we shall take the reader through the Rue de Buffon, into the new buildings which contain the chemical laboratory of M. Fremy, the botanical laboratory of M. Brongniart, and the laboratory of vegetable physiology and anatomy of M. Decaisne.

M. Fremy had already, for many years, assembled his pupils in the old Museum buildings, badly lighted, small, confined, where they were very uncomfortable; now, on the contrary, they are installed in a new building where they are furnished with every convenience for their work.

As soon as we enter the court, we find on the right and left, platforms (paillasses) in the open air with a glass roof, where all experiments can be made, of a nature to taint the atmosphere of the laboratories. On each side are ranged buildings, one specially intended_for beginners, the other for more advanced students. The latter is provided with furnaces, by means of which the

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highest temperatures may be obtained. Each pupil has his place marked out, his name inscribed upon the frame above his work-table, which is furnished with a set of drawers and a rack for holding the matériel appropriate for his special work. The laboratory of the assistant naturalist, M. Terreil, and the preparatory laboratory, are situated in a line with the pupils' laboratory.

The bottom of the court opens into a lobby which communicates with the two wings of the building; here are conveniences for depositing the clothes which the students exchange for their working garb on entering the laboratory. A door in this corridor gives access to an antechamber into which open the laboratories of M. Fremy, and that of his special assistant, placed side by side.

The first and second stories of the buildings on the right and in the centre are intended for the botanists of M, Brongniart, who have not yet obtained complete pos*From an article in La Nature, No. 1,

session; the left wing belongs as yet to chemistry; on the first story is the lecture-hall, on the second the library.

M. Fremy has realised the foundation of a true school of chemistry; not only does he lavish on his pupils his instructions, but he sees that their education is complete. Every day at three o'clock work in the laboratory ceases, and oral instruction begins, the lecture-hall, moreover, being open to the public. M. Fremy gives instruction in general chemistry, with a well-known power of exposition; M. Terreil has charge of analysis; M. Ed. Becquerel, of the Institute, initiates the students in the management of physical apparatus; Jannetaz, assistant in mineralogy, gives instruction in that branch; and lastly, M. Stanislas Meunier, already known by his researches upon meteorites, treats of all the parts of geology which are connected with chemistry. Examinations are held by the lecturers for the purpose of testing the work of the pupils, who are rewarded at

the close of their studies with certificates testifying to their diligence and their acquirements.

All this instruction is absolutely gratuitous. M. Fremy wishes to remain faithful to the old motto of the museum, "Tout est gratuit dans l'établissement," though this excessive liberality is perhaps open to criticism.

Behind the magnificent chemical rooms we found the modest laboratory of M. Decaisne. Descending a few steps we reach a garden set apart to experiments in culture, having on the left a glazed gallery: this is the laboratory of vegetable anatomy and physiology. M. Decaisne superintends and advises the anatomists during his daily visits; M. Dehérain, who is well known for his researches in agricultural chemistry and vegetable physiology, directs the work of the laboratory represented in our illustration. It is a long apartment, perfectly lighted, into which stream the rays of the sun, that plays so important a part in all the phenomena of vegetable life; on the right, ventilators carry off all the strong-smelling gases which the chemist is obliged to employ ; long tables, furnished with earthenware vessels, extend along the middle of the apartments as well as underneath the windows. Everything is scrupulously tidy.

This laboratory of agricultural chemistry will no doubt yield to agricultural chemistry important results. The man of science will have here the means of preparing at pleasure true artificial soils; he will see plants of various kinds grow under his eyes; he will nourish them with organic and mineral substances whose composition is known to him. He will follow step by step the various phases of vegetable life; he will study the yet mysterious laws of vegetable life. Indeed it is difficult to state all the powerful resources that are in the hands of the experi

menter.

AERIAL SPECTRES

IN
N an article on the above subject in La Nature, No. 4,
M. G. Tissandier gives the following account of what
he saw from a balloon on February 16, last.

At mid-day we quitted the earth wrapped in a thick mantle of fog; after traversing the mass of the clouds, we were suddenly dazzled by torrents of light which shot

have, in addition, "the light that never was on sea or land."

When our balloon had passed about 50 metres beyond the plain of clouds, its shadow was projected with remarkable precision, and a magnificent circular rainbow appeared round the shadow of the car. Fig. 2 gives a very exact idea of the phenomenon. The shadow of the car formed the centre of rainbow-coloured concentric circles, in which were distinctly seen the seven colours of the spectrum, violet, indigo, blue, green, yellow, orange, and red. The violet was inside, and the red on the outside, these two colours being at the same time those which were scen with the greatest distinctn ss. We were,

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FIG. 1.-Shadow of a balloon surrounded by three aureoles. rom a tropical sun, a stream of fire, in the midst of an azure sky. Neither the mer de glace nor the snowy fields of the Alps, give an idea of the plateau of mist which stretched under the car like a glassy circle, in which valleys of silver appeared in the midst of flakes of gold. Neither the sea at sunset nor the ocean waves when lighted up by the orb of day at noon, approach in splendour this array of circular cumulus, but which

G. 2.-Optical phenomenon observed from a ba loon.

at the time the observation was made, at a height of 1,350 metres above the level of the sea.

The balloon, the gas in which expanded under the heat of the sun, continued to rise rapidly in the air, its shadow visibly diminishing; soon, at a height of 1,700 metres, the rainbow-circle enveloped it entire'y, and disappeared from around the car. A little later, at about 1h 35m, we approached the bed of clouds, and the shadow was girt this time by three silver-coloured aurioles, elliptical and concentric, as shown in Fig. 1.

Nothing can give an idea of the purity of these shadows, which are cut out in an opaline mist, or of the delicacy of tone of the rainbow which surrounds them. The complete silence which reigns in the aërial regions, where this play of light is seen, the absolute calm which

exists there, above clouds transformed by the sun into flakes of light, adds to the beauty of the spectacle, and fills the soul with inexpressible admiration.

We do not yet know exactly to what cause to attribute the production of a luminous contour around the shadow projected upon vapours or mists. Some observers have thought that these phenomena are due to the diffraction of light, but it is possible that they have a common origin with the rainbow. What tends to confirm this opinion is the necessity for the presence of the vapour of water as a necessary condition of the phenomenon: if it is the result of diffraction, it ought to appear as well upon a white wall, or any kind of screen, as upon a cloud. It is possible, moreover, to study these curious phenomena by means of experiments upon the earth; by suitably arranging screens of silk or muslin saturated with water. which resemble a cloud, we may expect to be able to produce the phenomenon. M. Leterne points out another excellent method of studying it. On a spring morning, when the sun, about 15 or 20 degrees above the horizon, has warmed the atmosphere a little, and has produced a light condensation of vapour upon the grassy borders of the roads, one may see his silhouette projected upon the humid verdure, surrounded by a luminous contour, in which is seen the colours of the spectrum, the red, however, being strongest.*

GEO

THE GEOLOGICAL SURVEY OF INDIANA EOLOGY is a branch of Science which specially commends itself to the fostering care of Governments, paternal or otherwise. More particularly is this true of a new country, where, in the imagination of the settlers, untold wealth has yet to be dug out of the earth, if only they could discover in what quarter best to look for it. Accordingly, in not a few of our colonies and in a number of the States of the Union, geological and mineralogical surveys have long been at work, originated and continued at the public expense. In most cases, of course, the first aim of such surveys, and in fact the very justification of their existence in the eyes of practical and by no means scientific legislators, is the finding of mineral wealth. If they were begun from the lofty scientific point of view they would fail, and deservedly. But when a really able scientific man gets the charge of one of them, and has at the same time that mother-wit and knowledge of the world which scientific men so often lack, he may not only attend to the rigid economics of his paymasters, but do great service to geology. His aim is to show the public that a strictly scientific basis is the only one on which a mineral survey to be of any value can be conducted. And this is so obvious that if it is simply and clearly stated, it for the most part commends itself to the common-sense of public men. In laying this necessary basis and then in carrying out the survey for economic minerals the geologist may both pave the way for an enormous increase to his country's industry and wealth, and add much of permanent interest and importance to the common stock of geological knowledge.

Perhaps the most notable illustration of the successful accomplishment of this double mission is furnished by the career of Sir William Logan, whose practical kindly ways enabled him to triumph over the shortsightedness of colonial obstructionists, and whose patient and sagacious labours among the rocks of Canada have made his name honoured and familiar all over the world, and have conferred distinction also upon his country. In the United States, too, fostered by the liberality of the Legislatures, a number of admirable State surveys have been made, or are still in progress. Under the auspices of such men as James Hall, Owen, the Hitchcocks, the brothers Rogers, Hayden, Whitney, Blake, Cook, and others, not only have maps been constructed, but elaborate reports have *Comptes Rendus, t. lxxvi. p. 786

been published, embracing, in addition to the paramount economics, much valuable information in geology, mineralogy, and paleontology.

One of the latest of these State surveys is that of Indiana, which was started some four years ago under the direction of Prof E. T. Cox. Like those already referred to, it was organised by the authorities "for the purpose of collecting information designed to promote the interests of agriculture, arts, manufactures, and mining." But it was furnished at the same time with an analytical laboratory "for analysing such ores and substances as may be deemed useful to the State," and with space "to build up a geological and natural history cabinet," while in order to render its labours as speedily serviceable as possible, an annual report of progress was required to be issued.

Prof. Cox has evidently a hard task before him. He has been invited to become a kind of depository of all the mining information in the State. He is to see that trustworthy mineral surveys are made, and at the same time he is expected to look after the laboratory and infant museum at Indianopolis and-perhaps most laborious but not least useful of all-to receive everybody who wants to know about coal, iron, or other mineral produce, and to collect and furnish to such inquirers all the information procurable. He generously says in one of his reports that this latter part of his duties "has always given him pleasure," though he confesses that it has consumed a considerable portion of his time. Fortunately he can count on the help of a small but apparently able staff of assistants, and notwithstanding all the obstacles in his way he has succeeded in getting through a large amount of work which, though not yet of high scientific value, must bear most importantly upon the future development of Indiana.

Three volumes of reports with maps have been published, bringing the account of the progress of the Survey up to the end of last year. Each of these neatly printed and not too bulky octavos describes several counties of the State with reference chiefly to the distribution of economic minerals; and the maps which accompany it, though roughly and cheaply executed, are clear and must be of infinite service to the many speculators and others who every year come in increasing numbers into the state in search of mineral investments. The coal-field of Indiana, though only a part of the larger basin of Illinois, is estimated to equal more than half of the area of the whole of the coal-fields of Great Britain and Ireland. Some of the coal-seams are of excellent quality, specially that known locally as "block-coal," which is said to be unrivalled for iron-furnaces. Abundant iron ore likewise occurs. Hence not only coal-pits but iron-works are springing up in rapidly increasing numbers. Not a little of this wonderful rapidity of growth is attributed by Prof. Cox, and no doubt justly, to the extended and more accurate knowledge of the minerals which the Survey has been able to publish. In the course of two or three years tracts of "primeval forest " have vanished, and in their place the visitor would now see clanking engines and mining villages, crowded with a population as busy and begrimed as any to be met with in Staffordshire or Lanarkshire. And yet vast though this change is, it may be said to have only just begun. Before many years are over the coal-bearing part of the formerly quiet agricultural state of Indiana will become one of the most active centres of industry in the Union, with railways diverging in all directions to carry away its mineral produce.

Prof. Cox and his assistants have not only been successful in pointing out the mineral resources of the various counties. In looking through his reports one can see that he continues from year to year to slip in more of general scientific interest. This is notably the case with the volume lately published. In addition to a series of

elaborate analyses of coals, we find that in the coal-pit sections the names of characteristic fossils have found their way into the text, that notices are given, not merely of the economically useful minerals, but of the geological formations which have no special industrial value,-Silurian, Drift, River-terraces, &c. The volume contains also meteorological tables and notices of recent geological changes. But by far the most interesting 'contribution to science in its pages is a" Report on the Wyandotte Cave and its Fauna," contributed by Prof. E. D. Cope, with an account of the geology of the cave, by Prof. Cox himself. This remarkable cavern runs through the "sub-carboniferous" limestone in numerous branches which are said to have a total length of twenty-two miles, and greatly to excel the more famous Mammoth cave of Kentucky in the number and beauty of their stalactites. It contains a peculiar fauna, numbering at least sixteen species, which show a general resemblance to those of the latter cave, and include one species of blind fish (Amblyopsis spelaus) which lives in the subterranean waters of Kentucky.

In these Reports each county is described separately, so that the same geological facts require to be frequently repeated. This is, doubtless, the most useful arrangement for those for whom the volumes are primarily intended. But it would be a service to other readers if a good table of contents were given, and if the index were made much fuller, especially in matters of general geological interest. The volumes are eminently praiseworthy, and we hope to see them followed, before long, by a good map and a general geological Report of the whole State of Indiana. A. G.

INTELLECT OF PORPOISES

A SINGLE visit to the Brighton Aquarium would

suffice to convince a recent correspondent, Mr. Mattieu Williams, that the intellect of the porpoise, as foreshadowed by its convoluted brain, exceeds, beyond comparison, that of the cod-fish or any other representatives of the piscine race. Of the two specimens now inhabiting the largest tank in the building, over one hundred feet long, the first-comer so readily accommodated itself to its altered conditions, that on the second day it took its food, smelts and sprats, from its keeper's hand, and has continued to do so ever since. The later arrival was, at first, less sociably inclined; but both have latterly become equally tame, and frequently, while receiving fish from my hand with the gentleness of pet dogs, have permitted me to pat and stroke their slippery india-rubberlike backs.

During feeding-time it is amusing to watch the avidity with which these porpoises take their food; one, the more active of the two, usually securing the lion's share, and displaying marked sagacity by frequently snatching a second or third morsel before disposing of the first,

The keeper in charge of these interesting animals is now in the habit of summoning them to their meals by the call of a whistle; his approaching footsteps, even, cause great excitement in their movements, and recent experiments have proved them to be acutely sensitive to the vibrations of sound. By the physiologist a more pleasing spectacle can scarcely be witnessed than the graceful actions of these cetacea, as they swiftly pursue their course up and down their spacious tank, ascending to the surface of the water at intervals of fifteen or twenty seconds, to breathe, each inspiration being accompanied by a spasmodic sob-like sound, produced by the rush of air as a breath is rapidly liberated and inspired through the single central blow-hole.

Onward progress is effected in these animals, as in all other cetacea, exclusively by the action of the horizontal caudal fin; the development of muscle at the "wrist" of the tail on which this action depends being enormous and

plainly visible externally; the pectorals are devoted principally to the purpose of steering the creature to the right or left, aiding it also in rising to the surface of the water. The fact alone of the porpoise suckling and evincing much maternal solicitude for the welfare of its young indicates the superiority of its position in the zoological scale above that of the other representatives of the finny tribe; and to this, in addition to the remarks just made upon their sagacity when feeding, many other facts may be cited, pointing in the same direction. The curiosity attributed to these creatures, as illustrated by the experiences of Mr. Mattieu Williams, receives ample confirmation from their habits in confinement. A new arrival is at once subjected to the most importunate attention, and, advancing from familiarity to contempt, if disapproved of, soon becomes the object of attack and persecution. A few dog-fish, Acanthias and Mustelus, three or four feet long, placed in the same tank, soon fell victims to their tyranny, the porpoises seizing them by their tails, and swimming off with and shaking them in a manner scarcely conducive to their comfort or dignified appearance, reminding the spectator of a large dog worrying a rat. The fine sturgeon, six feet long, now sharing an adjoining tank with the cod, was first placed with these animals, but in a short time was so persecuted that for safety it had to be removed; while to this day the lacerated condition of its tail bears witness to the pertinacious attention of its former comrades. Some large skate (Raja clavata and maculata), while they maintained their usual habit of lying sluggishly on the floor of the tank, escaped molestation; but no sooner did these fish display any unwonted activity than the porpoises were upon them, and, making a convenient handle of their characteristic attenuated tails, worried them incessantly. On one occasion I witnessed the two Cetacea acting evidently in concert against one of these unwieldy fish, the latter swimming close to the top of the water, and seeking momentary respite from its relentless enemies, by lifting its unfortunate caudal appendage high above its surface. It need scarcely be remarked that the skate were removed before further mischief could be done, leaving the porpoises, with the exception of a few conger, which during the day-time mostly lie hidden in the crevices of the rock-work, turtles, and a huge monk-fish (Rhina squatina) sole occupants

of this colossal tank.

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