Изображения страниц
PDF
EPUB

Geological Climates

It was with great surprise I read Prof. Haughton's unqualified statement in last week's NATURE, that—"It is impossible to suggest any rearrangement of land and water which shall sensibly raise the temperature of the West of Europe,"-since I had, as I thought, in my recently-published volume-Island Life"-not only "suggested" such a rearrangement, but also adduced much evidence to show that it had actually occurred throughout the periods when both the West of Europe and the Arctic regions enjoyed a much higher temperature than they do now. now briefly re-state my "suggestion," and will also make a few remarks on the general causes of difference of temperature, which may serve to render the subject more intelligible.

I will

It is now well known that places in the temperate zones owe their temperature at different seasons only partially to the amount of direct sun-heat they receive, but very largely to the amounts of heat brought to them by currents of air. Thus we explain, not only the mild winter climate of our islands as due to the prevalence of westerly and south-westerly winds which have become warmed by passing over the Atlantic, but also the wonderful inequality of temperature at different seasons of the year. When we have warm spring-like days in mid-winter, it is because these warm currents of air are passing steadily over our islands; while continued hard frosts are as clearly due to masses of cold air from the north or north-east which drift down to us, often with no perceptible wind. Again, when in April and May we have days as cold as those of December and January, they can always be traced to northerly or easterly currents of air, and are probably often connected with the southern drift of the icebergs at that season. It is clear then, that if south-westerly winds were to continue throughout the winter, the severity of that season would be entirely abolished; and the same effect would be produced if by any means the winds from the north and east lost their severity.

Now the source of the constant warmth of our westerly winds is admitted to be the influx of warm water into the North Atlantic-chiefly by the Gulf Stream; and this warm northward flow of tropical water, being primarily due to the trade-winds, is not confined to the Atlantic, but is equally present in the other great oceans, and similar effects are produced in them, though nowhere to so great a degree as in our islands, owing to our insular position and the great extent to which Europe to the east of us is permeated by water as compared with North America or Asia. The North Pacific, with its great Japan current, is probably quite as warm as the North Atlantic; but Vancouver's Island, though further south than London, has not so mild a climate; and this can be clearly traced to the great mass of land to the east and north of it, the lofty snow-clad mountains, and the absence of those deep gulfs and inland seas which do so much to ameliorate the climate of Europe.

Prof. Haughton states, in his "Lectures on Physical Geography," that the Kuro Siwo, or great Pacific current, is two and a half times as large as the Gulf Stream, while the Mozambique current, which forms the outflow of the warm waters of the Indian Ocean, is one and a half times as much, so that these two currents have together four times the bulk and heating power of the Gulf Stream. If therefore these two currents at any time obtained an entrance into the Arctic Ocean, it is difficult to over-estimate their effect on its climate. The Gulf Stream, of which probably not half passes northwards of our islands, gives to Iceland the same winter temperature as Philadelphia, and keeps the North Cape (far within the Arctic circle) permanently free from ice, and this, notwithstanding the powerful counteracting influences of the lofty Scandinavian mountains on the one side, and the huge ice-clad plateau of Greenland on the other. Suppose that only an equal proportion of the Kuro Siwo entered the Arctic Ocean, is it not probable that no seaice at all would form there? While, if Greenland were less elevated and thus ceased to be an accumulator of ice, the combined effect might be to render the whole Polar area free of icebergs. This would at once do away with the chief source of winter cold to all north temperate lands, and ameliorate the climate of America as much, proportionately, as that of Europe.

But we have yet to consider a still more powerful agent in ameliorating the climate of Western Europe in Secondary and early Tertiary times. The heated waters of the Indian Ocean have now no northern outlet, and only penetrate the continent in the sub-tropical Red Sea and Persian Gulf. Now if we suppose the waters of the Bay of Bengal and the Arabian Sea to have had northward outlets through the heart of the Euro-Asiatic

continent, penetrating in two or more directions into the then much more extensive Arctic Ocean, we should have an agency at work which would render the presence of any permanent ice in the North Polar area as impossible as it is now in Scotland. The cooling agency of ice being once abolished, the comparatively small area of the Polar as compared with the Tropical seas (about one-tenth) would facilitate the raising of the temperature of the former to perhaps 15° or 20° F. above the freezing point, and this would not only give the Arctic lowlands a climate quite sufficient for the vegetation which we know they supported, but, by doing away with the only source of our winter cold, would give our islands a perfect immunity from frosts and render them capable of supporting the vegetation now characteristic of sub-tropical lands.

That the modifications of land and sea here indicated did exist throughout a considerable portion of past geological ages, and that the existing consolidation of the great northern continents, to which the possibility of our present Arctic climates is mainly due, is a comparatively recent and abnormal phenomenon, I have At endeavoured to prove in the work already referred to. present I have only undertaken to show, that a "suggested" rearrangement of land and water adequate to raise the temperature of Western Europe to a very sensible, or even to a very large extent, is "possible." ALFRED R. WALLACE

Photophonic Music

I HAVE not yet met with any reference to the capabilities of the photophone for giving musical harmonies. Might not some curious effects be got in some such way as this:-Suppose a disk perforated with holes in four concentric circles corresponding to the notes of a chord; a beam of light to be sent through each circle to a lens and disk of rubber with tube (as Prof. Bell has described), the four tubes debouching in a cup-shaped cavity to be applied to the ear; lastly, the disk to be rotated variably by means of a small windmill or otherwise. Another arrangement might be to make the beams cf light pass through the holes to selenium cells in four telephone circuits, the four telephones being placed in one frame, against which the listener's ear would be put, or coupled in pairs, one pair put to either ear. Again, might not harmonised tunes be obtained thus:-Suppose a broad open drum of wood or cardboard rotated uniformly on a screw forming a vertical axis. The drum is perforated in a spiral band of four lines of holes (for the light), corresponding to the notes of the harmonised air to be produced. This spiral band passes before four rubber disks or selenium cells (as in the former system), but arranged vertically and placed within the drum, at the lower part. The drum, it will be understood, works gradually down the axis, presenting a continuous four-line series of holes before the receiving apparatus. Again, a long continuous strip of cardboard, with four rows of holes, might be passed before the receiver in any convenient way.

The "Philosophy of Language"

M.

THOUGH it is my principle never to answer any criticism of my writings, I find myself obliged to deviate for once from this rule by the character of your highly esteemed review, and by the desire to find a discerning appreciation from your readers, whose judgment has for me the greater value, as it is the main aim of all my works to restore the relations between the science of mind and natural philosophy. Therefore you would oblige me very much by publishing the following short remarks :

The critic of my brochure ("Max Müller and the Philosophy of Language,") says, "... Nor is speech the deliberate product of a conscious will." Now it is the real aim of all my works on the philosophy of language to show how the human willbefore dark and unconscious-grows to consciousness by language and human activity intimately connected with it. Can there be the least doubt of this, even if I refer only to the motto of my "Origin of Language," "Language has created reason, before language man was without reason"?

Your critic has made me say just the contrary of what I really have said. Besides, it would have been only fair if the critic had pointed to the following little passage of my brochure :— "Max Müller has since expressed his full assent to this view," (viz., my theory of the origin of language). Mayence, November 11

LUDWIG NOIRÉ

[I gladly accept the author's assurance that he adheres to the view that "language has created reason." At the same time his

express words as well as the general bent of his argument seemed to point in the opposite direction. Thus at p. 81 he writes :"Language is a product of association. . . . Language is a product of an active, not of a passive, process; it is the child of will, not of sensation." The statement that language is "the child of will" seems to me practically identical with the assertion that "speech is the deliberate product of a conscious will," because the will here spoken of, being "an active process," is necessarily conscious.-A. H. KEANE.]

Notes on the Mode of Flight of the Albatross WHEN watching the albatross one is struck with the fact that the bird gets up to windward without appearing to use his wings to a degree sufficient to account for the same. The sailors are satisfied with the explanation that he beats to windward. The conditions are of course not analogous to those of a ship sailing to windward. If the wind be very light, or if there be a calm, occasional powerful and obvious flapping of the wings occurs. If there is no wind, the birds often settle on the water round the ship. In very heavy weather the birds disappear altogether, probably settling on the water. Except that for breeding they resort to the islands, I believe they frequent the open ocean, where the surface is seldom without more or less swell.

On watching the flight of the albatross, one observes that in order to rise from the water violent and obvious flapping of the wings is necessary, which is continued some time after the wings cease to strike the water. After a start has thus been effected, if there is a fresh breeze, the wings are kept almost motionless. Sometimes the bird goes some distance with the impetus derived from the flapping of the wings at the start, but sooner or later he turns so as to expose the plane surface of his wings full to the force of the wind, rising at the same time some height above the water, and drifts off to leeward, thus soon acquiring the velocity of the wind; then swooping down into the hollow between two swells, he turns his head to windward, and keeping close to the surface of the water, sails along more or less against the wind for a surprising distance; finally, rising over the crest of a wave comparatively high into the air, and turning with his wings as before, so as to catch the wind to the fullest extent, he again lets himself drift off to leeward.

Thus the manoeuvre he performs seems to consist in drifting with the wind in such a way as to attain its velocity very soon, and then turning round so as to make use of this velocity to carry him in the contrary direction.

Of course if he still remained exposed to the wind which had imparted to him its velocity he would not travel far against it before he came to a standstill, and he would certainly make no progress to windward; but by keeping close to the surface of the water, and as much as possible in the hollows between the waves, he is almost out of the wind; and in this comparatively calm region the impetus derived from the wind will carry him a long distance in exactly the opposite direction to that of the

wind itself.

This manoeuvre appears to be an important factor. No doubt the almost imperceptible movement of the wings may assist, though that this alone is insufficient to account for the progress to windward appears evident from the powerful efforts made with the wings in rising from the water and in calm

weather. I have never had an opportunity to observe the albatross flying over land or over level water. If the manoeuvre above described be an important factor, the bird; then would have to use their wings much as they do in very light winds on the ocean. If very strong winds were blowing, they would have to settle on the land or in the water in order to remain at the locality. ARTHUR W. BATEMAN

A General Theorem in Kinematics

[blocks in formation]

YOUR correspondent "P. C." (NATURE, vol. xxii. p. 607) asks information concerning a work, in English or French, on geometrical optics, thoroughly explaining the optical construction of telescopes and microscopes. I am not aware of any such publication these last forty years, but deem it possible that it may interest your correspondent to know of the existence of such a work in German by von Littrow, entitled "Dioptrik, oder Anleitung zur Verfertigung der Fernröhre." It was published, I believe, in Vienna about 1838. W. G. LOGEMAN

High Burghal School, Haarlem, Holland, November 17 [Littrow's "Dioptrik " was published at Vienna in 1830 in Svo.-ED.]

Ozone

IF a slip of the prepared paper, used for testing for atmospheric ozone, be carefully moistened on one side with alcohol, using a clean camel-hair brush, on burning off the spirit and immersing the slip of paper in water the paper changes to a deep purple colour, as deep as No. 8 in Negretti and Zambra's scale of colours for ozone.

Is this due to the development of ozone? as, according to Schönbein, heat destroys ozone. Leicester, December 5

J. P.

PLANTS OF MADAGASCAR URING the present year no less than four separate collections of plants have been received at Kew from Madagascar, including in the aggregate about a thousand species, represented by specimens complete enough to be botanically determinable. As the hills of the interior of the island attain an elevation of 10,000 feet, its range of climate is considerable. We now know not less than two thousand Madagascar flowering-plants, and probably have almost exhausted its ferns, to which the collectors have paid special attention, and which are about 250 in number, so that we may consider ourselves in a position to draw broad general conclusions as to the botany of the island.

Amongst the tropical types there are a considerable number of endemic genera. The lemurs find their parallel in the vegetable kingdom in the Chlanacea, a natural order whose nearest affinities are with Tiliacea, Dipterocarpea, and Ternstromiacea, which is strictly confined to Madagascar, and comprises four genera and about twice as many species, to which the Rev. R. Baron, in these new collections, has added a well-marked novelty in a second species of Leptolana. Altogether there are certainly not less than fifty genera confined to the

island, some of them very curious types, as Dicoryphia in Hamamelidea, Ouvirandra in Naiadacea, Asteropeia (placed in the "Genera Plantarum" in Samydacea, but which Mr. Baron's excellent new specimens will most likely have to be removed to Linacea), Macarisia in Rhizophorea, Deidamia and Physena in Passiflorea, Hydrotriche in Scrophulariacea, Canetia, Tannodia and Sphærostylis in Euphorbiacea, Pachnotrophe in Morea, Calantica in Samydacea, and several each in the orders Rubiacea, Melastomacea, and Composite. To these endemic types the new collections add at last three, Kitchingia, a fine new genus of Crassulaceae allied to Bryophyllum, with five or six species named after the collector of the first of the four parcels, Rhodocodon, a monotypic genus of

PROF. EVERETT (ante, p. 99) has overlooked in the introductory paragraphs of Prof. Schell's paper, to which he refeis for the original statement of the theorem re-discovered by Prof. Minchin, the acknowledgment: "Der Mittelpunkt der Beschleunigungen und jene beiden Kreise wurden bereits 1853 von BRESSE gefunden." The reference is to the Journal de l'Ecole Polygamophyllous Liliacea allied to Hyacinthus, and Microtechnique, tom. xx., "Mémoire sur un Théorème nouveau concernant les Mouvements Plans, etc." By means of the two circles" Bresse determines the point c (7) "qui aura une accélération totale nulle" (p. 82), and then by very ingenious applica

nychia, in Anacardiaceæ, also monotypic, figured lately in Hooker's Icones. Besides these the tropical flora of the island contains a large proportion: first, of endemic species of genera known elsewhere; second, of species

common to Madagascar, Mauritius and Bourbon, but not elsewhere known, such as Pittosporum Senacia, Aphloia mauritiana, Gouania mauritiana, Nesaa triflora, Lobelia serpens, and Buddleia madagascariensis; thirdly, of species that spread across Tropical Africa, such as Haronga paniculata, Desmodium mauritianum and oxybracteum, Gynura cernua, Brehmia spinosa, and Mussoenda arcuata; fourthly, of species spread universally through the tropics of the Old World, but not reaching America, such as Crotalaria stricta, Oxalis sensitiva, Nymphæa stellata, Trichodesma zeylanica, Indigofera enneaphylla, Avicennia officinalis, and

cronata; and fifthly, of species spread universally through the tropical zone of both hemispheres, such as Eleusine indica, Tephrosia purpurea, Drymaria cordata, Elephantopus scaber, Terammus labialis, Zornia dephylla, Waltheria americana, Sida rhombifolia, and Nephrodium molle. In Mauritius and the Seychelles there are 145 species which occur also both in Asia and Africa, in addition to 225 which are spread all round the world in the tropical zone, and nearly all these 370 species are now known in Madagascar also. A small proportion of the Madagascar genera and species are Asiatic but not African, and these present collections add to the island flora Lagerstromia, Buchanania, and Strongylodon, three well-marked Indian types.

, 1880 Crotalaria spinosa reappears in Nubia, Abyssinia, Angola, and Zambesi-land; Asplenium Mannii, Hook., on the mountains of Zambesi-land, the Cameroons, and Fernando Po. As a whole, it would seem that the flora of the Madagascar mountains corresponds closely with that of the great ranges of the tropical zone of the main J. G. BAKER

African continent.

BENJAMIN COLLINS BRODIE, BART.,
F.R.S., D.C.L.

N
November 24 last, died Benjamin
ΟΝ
Collins Brodie the younger, a worthy son of a dis-
tinguished sire. Born to affluence, but early imbued with
the liberal and high-minded views of the great surgeon,
he determined to devote his life and energies to the
prosecution of science for its own sake, and well has be
done his work. Brodie was born in London in 1817, and
educated first at Harrow under Longley, and afterwards
at Balliol, taking his Master's degree in 1842. In those
days it was absolutely impossible to carry out original
chemical work at Oxford, and Brodie naturally betook
himself to Giessen, where Liebig's name drew students
from all parts of the world. There in the summer of
1845 Brodie, at Liebig's suggestion, carried out analyses
of certain waxes obtained by Gundlach by feeding bees
on different kinds of sugar. The results thus obtained
led him to continue his examination of bees'-wax on his
return to England, and from his private laboratory in the
Albert Road now came forth his well-known researches
on the Chemical Nature of Wax (Phil. Trans. 1848,
147-170; 1849, 91-108), for which in 1850 he received the
well-merited reward of the Royal Medal.
These re-
searches will always remain not only remarkable as
having given a successful solution of a difficult problem,
but as having proved, by careful preparation and exact
analysis, the existence in wax of solid bodies which play
the part of alcohols, and of which common spirit of wine
is a direct lineal descendant. This unexpected discovery
of solid alcohols containing respectively twenty-seven and
thirty atoms of carbon in the molecule completely con-
firmed the truth of the views concerning the existence of
an homologous series of alcohols first enunciated by Schiel
and Gerhardt, and thus placed in firm position one of the
chief pillars of the organic portion of our science.

But perhaps still more interesting, in the light that it throws on the past history of the island, is the relationship of the comparatively limited flora of the mountains of the interior to that of other parts of the world. A certain number of the plants, especially the ferns and fern-allies, are widely-spread temperate species, which now have their head-quarters in the temperate regions of the northern hemisphere; we have instances of this in Nephrodium Filix-mas, Aspidium aculeatum, Osmunda regalis, Lycopodium claratum, L. complanatum, Sanicula europea, Potamogeton oblongus, Sonchus asper, S. oleraceus, Polygonum minus. Most of the characteristic types of the Cape flora are represented on the Madagascar mountains, but nearly always by species which are distinct from those which are now found in the extratropical regions of the main continent for instance, the Aloes by a couple of species of Eualoe; the Heaths by several species of Philippia and Ericinella; the bulbous Iridacea by species of Gladiolus, Geissorhiza and Aristea; the saprophytic Scrophulariaceae by Harveya obtusifolia; Brodie's next work was not inferior either in importance the special Cape ferns by Mohria caffrorum, Cheilanthes or in workmanship to his first. In 1850 he published his hirta, Pellaa hastata, and P. calomelanos; the Proteacea memoir "On the Condition of certain Elements at the by the curious genus Dilobeia (which Du Petit Thouars Moment of Chemical Change" (Phil. Trans., 1850, 750found at the beginning of the century, and of which Dr. 804), in which he carefully investigates the remarkable Parker has now sent home the first specimens which have reducing action exerted by peroxide of hydrogen. Not been seen in England); and the Selaginea by Selago only does this body lose half its oxygen when brought in muralis of Bentham, which grows in the grounds of the contact with oxide of silver, but reduces this oxide to Queen's palace at Antananarivo. But perhaps the most metal. This anomalous action was satisfactorily exinteresting feature of all is the occurrence of several plained by Brodie, who pointed out that the second striking cases of specific identity between plants of the atom of oxygen in these peroxides is not only reMadagascar mountains and those of the tropical zone tained in an unstable state of combination, but that of the African continent. The only Madagascar violet when brought into contact with silver oxide a true (Viola emirnensis, Bojer, V. abyssinica, Steud.) only synthesis of oxygen occurs, two atoms of this element occurs elsewhere high up amongst the mountains of uniting to form one molecule of free oxygen. That this Abyssinia, at 7000 feet above sea-level in the Camaroons, reaction really takes place was shown by Brodie to be the and at 10,000 feet above sea-level at Fernando Po. The case by careful experiment. These results led him to only Madagascar Geranium (G. emirnense, H. B. G. consider the constitution of the alcohol radicals (Chem. compar, R. Br. = G. simense, latistipulatum and frigidum, Soc. Journ. iii. 405), and to assert in 1851 the important Hochst.) has a precisely similar area of distribution. Cau-fact, now universally admitted, that the molecule of the calis melanantha of Bentham is only known in Madagascar radical ethyl contains four atoms of carbon. To him and amongst the mountains of Abyssinia. The Mada- too we owe the prediction of the possibility of the gascar Drosera (D. madagascariensis, D.C. D. ramexistence of the mixed radicals, a prediction so soon entacea, Burch.) reappears at the Cape and the moun- afterwards experimentally verified by Wurtz. Next tains of Angola and the west tropical coast; Agauria we find him active as secretary of the Society of salicifolia, Hook. fil., which we noted lately as having which he afterwards became president, viz. the Chemical been gathered by Mr. Thomson on the high plateaux of Society of London; also in lecturing at the Royal InstiLake Nyassa, is found in the Cameroons and on the tution on the allotropic changes of certain elements, on mountains of Madagascar, Mauritius, and Bourbon; the formation of hydrogen and its homologues, in which

=

=

=

he clearly brings forward his views concerning the union of atoms to form the molecule.

In 1853 he published his interesting observations on the conversion of yellow phosphorus into the red modification by heating it to 200° in presence of mere traces of iodine (Chem. Soc. Journ. v. 289). Another very important and difficult investigation which occupied much of his attention about this time was the question of the purification (Ann. de Chimie, 45, 351) of graphite, and the determination of its "atomic weight" (Phil. Trans. 1859, 249). By heating graphite with strong nitric acid and chlorate of potash, Brodie showed that, unlike all the other modifications of carbon, graphite yields a remarkable crystalline acid, to which he gave the name of graphitic acid, having the formula CHO. The existence of this interesting body led Brodie to the conclusion that graphite may be considered as a peculiar radical, to which he gave the name of graphon. In the year 1855 Brodie was appointed Waynflete Professor of Chemistry in the University of Oxford, a position which enabled him to throw all his influence into forcing the recognition of chemical science as a proper object of academic training. Under his fostering care the science which had hitherto been so long neglected put out distinct signs of life: new laboratories and lecture-rooms were built, to which students flocked in numbers, and Oxford saw the unwonted sight of her professor of chemistry busily engaged in original investigation, as well as in the tutorial duties of his chair. The discovery of those singular and dangerous bodies, the peroxides of the organic radicals (Proc. Roy. Soc. ix. 361, Phil. Trans. 1863, 407), was made in the laboratory of the New Museum. The same laboratory soon afterwards saw the minute and careful investigation on ozone (Phil. Trans. 1872, 432), which proved beyond doubt or cavil that the supposition that the molecule of ozone is represented by the formula O, is both necessary and sufficient to explain all the observed phenomena.

Next we find him experimenting on the synthetic production of the hydrocarbon methane, as well as of formic acid, by the direct union of hydrogen and carbon monoxide under the influence of the electric spark. Then he examines the effect of an induced electric current upon pure and dry carbonic acid, and proves that this gas is partially decomposed with formation of carbon monoxide and oxygen, the latter gas being converted into ozone. And he then proceeds to ask whether the ozone thus produced is identical with that obtained from ordinary oxygen, and by a series of careful quantitative experiments demonstrates the identity of the ozone from these two sources.

This was Brodie's last experimental investigation. Ere long he resigned the Chair of Chemistry at Oxford, regretted by the whole University. He retired to his charming seat on the summit of Box Hill. Neither his own scientific activity nor his deep interest in the scientific work of others ceased on his withdrawal from professional life. Before his retirement he had put forward (Phil. Trans. 1866, 781-860) in his "Calculus of Chemical Operations," views altogether novel respecting the nature of chemical change. In place of the usual mode of considering this as due to a change in the relative positions of the atoms of which matter is composed, Brodie founds his theory of the constitution of chemical elements and compounds on the simple volumerelations discovered by Gay-Lussac to exist between these substances in the gaseous state. To hydrogen Brodie gives a simple symbol, because the unit of hydrogen can, as he expresses it, be conceived as made at once by one operation, whilst to oxygen he gives a double symbol, because it cannot, according to him, be made by less than two operations. The element chlorine is supposed to be made up of three operations, and a treble symbol is given to this body. Concerning the probable or possible decomposition of the elements Brodie naturally speculates. His analysis had led him to suspect that "chemical sub

stances are really composed of a primitive system of elemental bodies analogous in their general nature to our present elements, some of which we possess, but of which we possess only a few" ("Ideal Chemistry," p. 54). But no experimental evidence of this fact was offered by him, and none of a satisfactory character was otherwise forthcoming, until Victor Meyer announced his belief that chlorine was capable of undergoing decomposition at high temperatures.

Here was a proof of the truth of Brodie's complex symbol ! Sad to say, further experiment has not corroborated this conclusion. No substance differing essentially from chlorine has yet been got from this body. Even the change of density at a white-heat appears in the case of chlorine to be, to say the least, doubtful. So we are left for the present, and the author of the "Calculus of Operations" is left for ever,without the experimental confirmation of his conclusions which he so much desired. Whatever may be the verdict of the future as to the value of Brodie's Calculus, there is no doubt that science is indebted to him for an altogether new view of chemical combination obtained by a systematic analytical process.

This occasion is not a fitting one to enlarge upon the high personal character of the late Sir Benjamin Brodie. Suffice it to say that in all relations in life, in the domestic circle as in society, in the chair at Burlington House as in that at Oxford, he displayed all those qualities of heart and head which alone give dignity and sweetness to life, the possession of which ensures for his memory a lasting place in the minds of all those who were fortunate enough to count him amongst their friends. H. E. R.

THE PHYLLOXERA IN FRANCE THI HE new vine-disease, due to the Phylloxera vastatrix Planchon, has already caused much damage to the French vineyards and wine-production. From the taxes | arising from that national industry France derives a considerable part of her revenue; and this subject has consequently occasioned innumerable publications and investigations. Of the latter some have been empirical and without result; others, which were conducted scienti fically, have alone been of any use. It was moreover absolutely necessary to have an unswerving confidence in exact observations, in order to persevere in making experiments which are often disturbed and rendered apparently self-contradictory by the secondary and evervarying conditions of cultivation. These experiments have at last been crowned with success, and now there are decidedly good grounds for hope. For the last two years the public have shown a steadily increasing confidence in scientific methods.

One of the most distinguished chemists, a man of whom France is proud, and with whom readers of NATURE are well acquainted, especially as they were lately presented with his portrait and biography, M. Dumas, applied himself to the study of the Phylloxera, and pursued his task from day to day with keen determination, notwithstanding the attacks of some and the discouraging advice of others. It is his well-intentioned and unceasing diligence that we must thank for never having lost heart; it is to him that those results are due which are presently to be indicated. When the pébrinedisease was raging on silkworms in the South of France, it was by his personal suggestion and repeated encouragement that M. Pasteur agreed to devote himself to that difficult study; and it is the same gentle influence and guidance that have directed the present writer, together with several others, especially MM. Balbiani, Duclaux, and Mouillefert.

Henceforward the principal problems raised by the study of vine diseases are solved. They were solved one after another in regular order, as fresh light appeared and the ends to be aimed at became more definite. It cannot

[merged small][merged small][graphic][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][ocr errors][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][ocr errors][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed]

FIG 1.-Map showing the spread of Phylloxera in France from 1955 to 1372. (See NATURE, vol. x. p. 504.) against the indifference of a French Minister of Agriculture who tried to beat down a grant of 10,000 francs necessary for continuing the scientific investigation. On the same occasion he drew attention to the praiseworthy initiation

taken by the railway companies and by various private gentlemen. M. Tirard, the present Minister of Agricul

1 Académie des Sciences, February 23, 1874.

« ПредыдущаяПродолжить »