Dec. 12, 1878]

NATURE

tury (1759), in regarding cells as the result of the action of an organising power upon a matrix, and not as themselves influenc ing organisation, were adverse to the progress of histology. It is from Schleiden (1838), who described the cell as the true unit of vegetable structure, and Schwann, who extended this view to all organisms whether plants or animals, and gave its modern basis to biology by reasserting the unity of organisation throughout animated nature, that we must date the modern achievements of histological science. Seldom, perhaps, in the history of science has any one man been allowed to see so magnificent a development of his ideas in the space of his own lifetime as has slowly grown up before the eyes of the venerable Schwann, and it was, therefore, with peculiar pleasure that a letter of congratulation was intrusted by the officers to one of the Fellows of this Society on its behalf on the recent occasion of the celebration of the fortieth anniversary of Schwann's entry into the professoriate.

If we call up in our mind's eye some vegetable organism and briefly reflect on its construction, we see that we may fix on three great steps in the analysis of its structure, the organic, the microscopic, and the molecular, and, although not in the same order, each of the three last centuries is identified with one of these. In the seventeenth century Grew achieved the microscopic analysis of plant tissues into their constituent cells; in the 18th, Caspar Wolff effected the organic analysis (independently but long subsequently expounded by the poet Goethe) of plant structures into stem and leaf. It remained for Nägeli in the present century to first lift the veil from the mysterious processes of plant growth, and by his memorable theory of the molecular constitution of the starch-grain and cell-wall, and their growth by intussusception (1858), to bring a large class of vital phenomena within the limits of physical interpretation. Strasburger has lately (1876) followed Sachs in extending Nägeli's views to the constitution of protoplasm itself, and there is now reason to believe that the ultimate structure of plants consists universally of solid molecules (not, however, identical with chemical molecules) surrounded with areas of water which may be extended or diminished. While the molecules of all the inert parts of plants (starch-grains, cell-wall, &c.) are on optical grounds believed to have a definite crystalline character, no such conclusion can be arrived at with respect to the molecules of protoplasm. In these molecules the characteristic properties of the protoplasm reside, and are more marked in the aggregate mass in proportion to its denseness, and this is due to the close approximation of the molecules and the tenuity of their watery envelopes. The more voluminous the envelopes the more the properties of protoplasm merge in those of all other fluids.

It is, however, to the study of the nuclei of cells that attention has been recently paid with the most interesting results. These well-known structures, first observed by Ferdinand Bauer at the beginning of the century (1802), were only accurately described, thirty years later, by Robert Brown (1833). Up to the present time their function has been extremely obscure. The beautiful investigations of Strasburger (1875) have led him to the conclusion that the nucleus is the seat of a central force which has a kind of polarising influence upon the protoplasm molecules, causing them to arrange themselves in lines radiating outwards. Cell-division he regards as primarily caused by the nucleus becoming bipolar, and the so-called caryolitic figures first described by Auerbach exhibit the same arrangement of the protoplasm molecules in connecting curves as in the case of iron-filings about the two poles of a bar-magnet. The two new centres mutually retire, and each influencing its own tract of protoplasm, the cell division is thereby ultimately effected. This is but a brief account of processes which are greatly complicated in actual detail, and of which it must be remarked that, while the interest and beauty of the researches are beyond question, caution must be exercised in receiving the mechanical speculations by which Strasburger attempts to explain them. He has himself shown that cell-division presents the same phenomena in the animal kingdom, a result which has been confirmed by numerous observers, amongst whom I may content myself with mentioning one of our own number, Mr. F. Balfour. Strasburger further points out that this affords an argument for the community of descent in animal and vegetable cells; he regards free celldivision as derivable from ordinary cell-division by the suppres sion of certain stages.

Turning now to the discoveries made during the last five years in physiological botany, we find that no one has advanced this

subject so greatly as Mr. Darwin. In 1875 was published his
work on insectivorous plants, in which he ascertained the fact
that a number of species having elaborate structures adapted for
the capture of insects, utilised the nitrogenous matter which these
contain as food. The most important principle established in
the course of these researches was that such plants as Drosera,
Dionea, Pinguicula, &c., secrete a digestive fluid, which has led,
through Gorup Bezanez's investigations on the ferment in ger-
in the transmission of food-material, which marks a great advance
minating seeds, to a recognition of the active agency of ferments
in our knowledge of the general physiology of nutrition.

The extreme sensitiveness of the glands of Drosera to mechanical and chemical stimulus (especially to phosphate of ammonia), the directive power of its tentacles, depending upon the accurate transmission of motor impulses, and the "reflex" excitation of secretion in the glands, were all discoveries of the most suggestive nature in connection with the subject of the irritability and movements of plants. The phenomenon of the aggregation of the protoplasmic cell-contents in the tentacles of Drosera is a discovery of a highly remarkable_nature, though not yet thoroughly understood. Lastly, Mr. Frank Darwin, following his father's footsteps, as it were crowned the edifice by showing to what an extent insectivorous plants do profit by nitrogenous matter supplied to their leaves.

In close relation to these researches are those, also by Mr. Darwin, on the structure and functions of the bladder of Utricularia, which he has shown to have the power of absorbing decaying animal matter; and those of Mr. Frank Darwin on contractile filaments of extraordinary tenuity attached to the glands on the inner surface of the cups formed by the connate bases of the leaves of the teasel, and which filaments exhibit motions suggesting a protoplasmic origin. It is to be hoped that their discoverer will pursue his investigations upon these curious bodies, whose origin and real nature in relation to the plant and its functions is involved in obscurity.

The subject of the cross-fertilisation of plants, which, though a long-known phenomenon, first become a fruitful scientific study in Mr. Darwin's now classical work, "On the Various Contrivances by which Orchids are Fertilised," has within the last few years made rapid advance under its author's hand. The extreme importance of avoiding self-fertilisation might indeed be inferred from the prevalence in flowers of elaborate contrivances for preattended cross-fertilisation, and this has now been proved by an venting it; but it remained to be shown that direct benefit elaborate series of experiments, the results of which are not only that both increased fertility or greater vigour of constitution attend cross-fertilisation, but that the opposite effects attend selffertilisation. In the course of these experiments it became evident that the good effects of the cross do not depend on the mere fact of the parents being different individuals, for when these were grown together and under the same conditions, no As advantage was gained by the progeny; but when grown under different conditions a manifest advantage was gained. instances, if plants of Ipomea and Mimulus, which had been self-fertilised for seven previous generations, were kept together and then intercrossed, their offspring did not profit in the least; whereas, when the parent plants were grown under different conditions, a remarkably vigorous offspring was obtained. "On the Different Forms of Mr. Darwin's last work, Flowers," though professedly a reprint of his paper on dimorphic plants, published by the Linnean Society, contains many additions and new matter of great importance in reference to the behaviour of polygamous plants, and on cleistogamic flowers. Among other points of great interest is the establishment of very close analogies between the phenomena attending the illegitimate union of trimorphic plants and the results of crosses between distinct species: the sterile offspring of the crosses of the same species exhibiting the closest resemblance to the sterile hybrids obtained by crossing distinct species; while a whole series of generalisations, founded on the results of the one series of experiments, are closely paralleled by those founded on the other. The bearing of this analogy on the origin of species is obviously important.

Besides these investigations, Mr. Darwin has produced within the last five years second editions of his volume on the "Fertilisation of Orchids," and on the "Habits and Movements of "Coral Reefs," Climbing Plants," as also of his early works on and "Geological Observations in South America ;" all of them abounding in new matter.

Of special interest to myself, as having been conducted in the

NATURE

Jodrell Laboratory at Kew, are Dr. Burdon Sanderson's investigations on the exceptional property possessed by the leaves and other organs of some plants which exhibit definite movements in response to mechanical, chemical, or electric stimuli. In 1873 this physiologist showed us in our meeting-room that the closing of the lamina of the leaf of Dionaa is preceded by a preliminary state of excitement, and is attended with a change in the electric conditions of the leaf; and this so closely resembled the change which attends the excitation of the excitable tissues of animals that he did not hesitate to identify the two phenomena.

This remarkable discovery immediately directed the attention of two German observers to the electromotive properties of plants, one, Dr. Kunkel, in the laboratory of Prof. Sachs; the other, Prof. Munk, in that of the University of Berlin.

Prof. Munk, whose researches are of much the greater scope and importance, took as his point of departure Dr. Burdon Sanderson's discovery. arrived was that in Dionaa each of the oblong cells of the paren· The leading conclusion to which he chyma is endowed with electromotive properties which correspond with those of the "muscle-cylinder" of animals; with this exception, that whereas in the muscle-cylinder the ends are negative to the central zone, in the vegetable cell they are positive; and he endeavours to prove that according to this theory all the complicated electromotive phenomena which had been observed could be shown to be attributable to the peculiar arrangement of the leaf-cells.

During the last two summers Dr. Burdon Sanderson has been engaged in endeavouring to discover the true relations which subsist between the electrical disturbance followed by the shutting of the leaf-valves of Dionæa and the latent change of protoplasm which precedes this operation. He has found that though the mechanism of the change of form of the excitable parenchyma which causes the contraction is entirely different from that of muscular contraction, yet that the correspondence between the exciting process in the animal tissues and what represents this in plant tissues appears to be more complete the more carefully the comparison is made; and that whether the stimulus be mechanical, thermal, or electrical, its 'effects correspond in each case. Again, the excitation is propagated from the point of excitation to distant points in the order of their remoteness, and the degree to which the structure is excited depends upon its temperature. Notwithstanding, however, the striking analogies between the electrical properties of the cells of Dionea and of muscle-cylinders, Dr. Burdon Sanderson is wholly unable to admit with Prof. Munk that these structures are in this respect comparable.

In morphological botany attention has been especially directed of late to the complete life-history of the lower order of cryptogams, since this is seen to be more and more an indispensable preliminary to any attempt at their correct classification.

The remarkable theory of Schwendener, now ten years old, astonished botanists by boldly sweeping away the claims to autonomous recognition of a whole group of highly characteristic organisms the lichens-and by affirming that these consist of ascomycetal fungi united in a commensal existence with alga. The controversial literature and renewed investigations which this theory has given rise to is now very considerable. But the advocates of the Schwendenerian view have gradually won their ground, and the success which has attended the experiments of Stahl in taking up the challenge of Schwendener's opponents, and manufacturing such lichens as Endocarpon and Thelidium, by the juxtaposition of the appropriate algae and fungi, may almost be regarded as deciding the question. Sachs, in the last edition of his "Lehrbuch," has carried out completely the principle of classification of alge, first suggested by Cohn, and has proposed one for the remaining thallophytes, which disregards their division into fungi and algæ. He looks upon the former as standing in the same relation to the latter as the so-called saprophytes (e.g. Neottia) do to ordinary green flowering-plants. This view has especial interest with regard to the minute organisms known as Bacteria, a knowledge of the life-history of which is of the greatest importance, having regard to the changes which they effect in all lifeless and, probably, in all living matter prone to decomposition. This affords a morphological argument (as far as it goes) against the doctrine of spontaneous generation, since it seems extremely probable that just as yeast may be a degraded form of some higher fungus, Bacteria may be degraded allies of the Oscillatoria, which have adopted a purely saprophytal mode of existence.

[Dec. 12, 1878

portant contributions to our knowledge of the lowest forms of Your Proceedings for the present year contain several im life. The Rev. W. H. Dallinger, continuing those researches which his skill in using the highest microscopic powers and his fruitful, has adduced evidence which seems to leave no doubt ingenuity in devising experimental methods have rendered so that the spores or germs of the monad which he has described differ in a remarkable manner from the young or adult monads monads, in fact, were always killed by five minutes' exposure to in their power of resisting heated fluids. The young and adult a temperature of 142° F. (61° C.), while the spores germinated point of water (222° F.). after being subjected to a temperature of 10° above the boiling

Two years ago, Cohn and Koch observed the development of
spores within the rods of Bacillus subtilis and B. anthracis.
tions, in these two species by Mr. Ewart, and have been extended
These observations have been confirmed, with important addi
to the Bacillus of the infectious pneumo-enteritis of the pig, by
thus a very important step has been made towards the completion
Dr. Klein; and to Spirillum by Messrs. Geddes and Ewart; and
of our knowledge of the life-history of these minute but im-
pneumo-enteritis, or typhoid fever of the pig, is, like splenic
portant organisms. Dr. Klein has shown that the infectious
fever, due to a Bacillus. Having succeeded in cultivating this
organisms, Dr. Klein inoculated healthy pigs with the fluid
Bacillus in such a manner as to raise crops free from all other
containing the Bacilli, and found that the disease in due time
distinctly proved that two diseases of the higher animals, namely,
arose and followed its ordinary course. It is now, therefore,
"splenic fever" and "infectious pneumo-enteritis," are gene-
rated by a contagium vivum.

into the influence of light upon Bacteria and other Fungi, which
Finally, Messrs. Downes and Blunt have commenced an inquiry
promises to yield results of great interest, the general tendency
of these investigations leaning towards the conclusion that
development of such organisms.
exposure to strong solar light checks and even arrests the

The practical utility of investigations relating to Bacillus
associating by community of origin various diseases of apparently
organisms as affording to the pathologist a valuable means of
different character, is exemplified in the "Loodiana fever,'
which has been so fatal to horses in the East.
of horses that had died of this disease in India has been recently
The dried blood
sent to the Brown Institution, and there afforded seed from
which a crop of Bacillus anthracis has been grown, which justi-
fied its distant pathological origin by reproducing the disease in
other animals. Other equally interesting experiments have been
made at the same Institution, showing that the "grains” which
peculiarly favourable for the development and growth of the
are so largely used as food for cattle, afford a soil which is
inspected, the anthrax fever can be produced at will, under con-
spore filaments of Bacillus; and that by such "grains" when
bearing of this fact on a recent instance in which anthrax
ditions so simple, that they must often arise accidentally. The
suddenly broke out in a previously uninfected district, destroying
grains obtained from a particular brewery, need scarcely be
a large number of animals, all of which had been fed with
indicated.

extending its dominions and exploring unknown regions of the In systematic botany, which, in a nation like ours, that is ever phytologists, I can but allude to two works of great magnitude globe, must always absorb a large share of the energies of its and importance.

completed only a year ago; a work which has well been called
Of these the first is the "Flora Australiensis" of Bentham,
unique in botanical literature, whether for the vast area whose
vegetation it embraces (the largest hitherto successfully dealt
with), or for the masterly manner in which the details of the
structure and affinities of upwards of 8,coo species have been
garding the geographical distribution of plants, the southern
elaborated; its value in reference to all future researches re-
hemisphere, and the evolution therein of generic and specific
types, cannot be over-estimated.

by our late foreign Fellow, von Martius, and now ably carried on
The other great work is the "Flora Braziliensis," commenced
by Eichler, of Berlin, assisted by coadjutors (amongst whom are
most of our leading systematists) under the liberal auspices of
His Majesty the Emperor of Brazil.
gigantic undertaking will have embraced, in a systematic form,
When completed, this
the vegetation of the richest botanical region of the globe.

NATURE

ticularly the attempt simply to depose the Church, and to replace its dogma by a religion of descent without further trouble-these attempts, I say, must fail, and their failure would at the same time bring the greatest dangers upon the position of science generally. After this every one will easily understand the joyful outbursts of the whole clerical press after Virchow's Munich address. It is known that there is ten times more joy in heaven over one repentant sinner than oven ten just men. Rudolf Virchow, the 'renowned materialist,' the 'radical If progressist,' the principal representative of the science, is suddenly so completely converted, if openly and ' atheism of loudly he proclaims the certain 'basis of instruction,' then, indeed, the combatant dogmas of the Church' as the only Church may sing 'Hosanna in excelsis! point to be regretted, and that is that Virchow has not stated There is only one which of the many different Church religions is the only true one, and which of the numberless and contradicting dogmas are to become the certain basis of education. each Church thinks itself the only one leading to eternal bliss, We all know that and its dogma the only true one. antism or Catholicism, Reformed or Lutheran confession, Now whether it is ProtestAnglican or Presbyterian dogma, Roman or Greek doctrine, Mosaic or Islamitic tenets, Buddhaism or Bramahism, or one of the fetish creeds of the Indians or coloured tribes which is to become the lasting and certain basis of instruction,' this, no doubt, Virchow will not hesitate to state at the next meeting of the German Association of Naturalists and Physicians.'

"At all events, the instruction of the future," according to Virchow, "will be very much simplified. Because the dogma of the Trinity as the basis of mathematics, the dogma of the resurrection of the flesh as the basis of medicine, the dogma of the infallibility as the basis of psychology, the dogma of the Immaculate Conception as the basis of the science of generation, the dogma of the stoppage of the sun as the basis of astronomy, the dogma of the creation of the earth, animals, and plants, as the basis of geology and phylogeny, these or some other dogmas from other creeds, will make all further doctrines rather superfluous. Virchow, this 'critical nature,' of course knows as well as I do, that these dogmas are not true, and yet, according to his view, they are not to be replaced as 'bases of instruction by the theories and hypotheses of modern natural science, of which Virchow says himself that they may be true, probably are true to a great extent, but have not been proved for certain' as yet." Finally, Haeckel points out that it seems to be bitter irony if Virchow, at the opening address, recalls the memory of Oken, whom he celebrates as the martyr of free science, and at the end of the same address demands that this "liberty of science" shall apply only to research, but not to instruction, and that no problems, no theories, no hypotheses are to be taught.

In Chapter VI. the application of the theory of descent to socialism is discussed. The author entirely endorses Prof. Oscar's Schmidt's view on the subject, and shows that the theory of descent and the socialistic theory are "like fire and water to one another." The theory of descent is, on the contrary, aristocratic in the highest sense of the word. Of course, from any theory, be it ever so true and sound, the most absurd deductions may be drawn if it is misapplied, and the author warns particularly against the misapplication of scientific theories to political or social questions. Theory and practice rarely correspond in human life. Haeckel points to the history of Christendom to illustrate his argument. "It is certain that the Christian religion, as well as the Buddhistic doctrine, if freed from all dogmatic fables, contain an excellent humane kernel; now it is just this humane and truly social-democratic part of the Christian creed, which proclaims the equality of all men before God, and preaches the 'Love thy neighbour as thyself,' in fact 'love' in its noblest sense, compassion with the poor and unfortunate, &c., -we say these truly humane sides of the Christian faith are so natural, so pure and noble, that we comprise them with pleasure amongst the moral laws of our monistic natural religion.

But what, we must ask, have the chosen representatives, the 'God-taught' (Gottgelehrte) priests, made of this 'religion of love'? It is written with letters of blood upon the pages of the history of mankind for the last 1,800 years! All that different Church religions have done for the forcible propagation of their creeds and for annihilation of 'heretics,' all that Jews have done against heathens, Roman Emperors against Christians, Mohammedans against Christians and Jews, all that is surpassed by the hecatombs of human victims which Christianity has slaugh

[Dec. 12, 1878

tered for the propagation of its doctrine. Christians against Christians. And indeed against wrongly-believing Christians. We need only think of the Rightly-believing Christians middle ages, of the Inquisition, of the unheard-of and inhuman cruelties which the 'most Christian kings' of Spain and their worthy thousands then died the most cruel death of fire, simply because colleagues in France, Italy, &c., have committed. Hundreds of they did not bend their reason beneath the yoke of the most flagrant superstition, and because their dutiful conviction forbade them to deny what they had recognised to be natural truths. action which was not then and up to the present day committed There exists no detestable, abominable, or inhuman in the name of and on account of true Christianity.' And what about the morals of priests, who designate themselves as servants of God's word, and whose duty first of all should be to regulate their own lives according to the teachings of Christianity? The long, uninterrupted, and horrible chain of crimes of all kinds which forms the history of the Roman pontiffs, gives ordinates, so did the 'rightly-believing' priests of other confes the best reply to this question. And as these 'representatives sions, not failing to establish as glaring as possible a contrast of God upon earth' have done, so did their helpmates and subbetween the practices of their own lives and the noble teachings doctrines, indeed to all doctrines which in the wide domain of of Christian love which they always talk about. What we have just said of Christianity applies to all other religious and moral retical kernel of these doctrines can always and everywhere form practical philosophy, in the education of the young, and the civilisation of the masses, are to show their power. The theothe greatest contrast with its practical application, according to the contradictory nature of man. But what does all this matter heeding what consequences may be drawn from his teachings by to the scientific investigator? His sole and only task is to find out truth, and to teach that what he has found to be true, unthe various parties in the State or Church.' ,,

In the last chapter Haeckel compares the "Ignorabimus speech of Dubois-Reymond (delivered at the Leipzig meeting in 1872) with Virchow's "Restringamur Munich, and refutes some of the views expressed by Dubois"address of Reymond, particularly the view that there are two insurmountable obstacles in the way of our completely understanding nature and the world, viz., the essence of matter and force and the human consciousness. Haeckel points out that even if the problems in question are not solved at present, no one has a right to declare them unsolvable. He then proceeds to explain the reasons why the opposition to the theory of descent has mainly originated amongst the biologists, and adduces examples from the history of Berlin science to show that a similar opposition to what have now become established truths, has repeatedly sprung from the same quarter. "It seems, indeed, to be the fate of the most interesting of all sciences, of the history of evolution, that its most important steps of progress and its greatest discoveries meet with the most powerful and lasting resistance. theory of descent, founded in 1809, had to wait during full Just as Wolf's fundamental epigenesis theory, which was founded fifty years before Darwin, in 1859, transformed it into the most in 1759, but was acknowledged only in 1812, so Lamarck's important acquisition of modern science. And how was this most comprehensive of all biological theories fought against George Cuvier silenced the most eloquent advocate of this theory, during this time, in spite of all progress of the empirical Geoffroy Saint Hilaire, in the midst of the Paris Academy, and sciences? Let us only remember how, in 1830, the celebrated how almost at the same time, in 1829, its founder, the great Lamarck, ended his laborious life, blind and in misery and poverty, while his antagonist, Cuvier, enjoyed the highest honour Saint Hilaire then contained the most important truths, while and the greatest splendour. And yet to-day we know that the despised and derided doctrines of Lamarck and of Geoffroy Cuvier's much-admired and generally-adopted creation doctrine Lamarck, could permanently impede the progress of free rehas been now abandoned generally as an absurd and empty Now if neither Haller against Wolff, nor Cuvier against search, then still less will Virchow succeed in crushing Darwin's admirable theory, even if he be assisted in an unenviable manner truth, we do not underrate the effect of his well-founded by the noisy Capuchin sermons of his friend Bastian. Much as authority upon wider circles. No doubt the hostile attitude we regret Virchow's hostile position in this great combat for

error.

gymnasia, but the number of pupils is not given. For females there are 223 gymnasia and pro-gymnasia, having 34,878 pupils ; and this does not include the many institutions which are subject to the control of the Fourth Division of the Imperial Chan cellery. There are 68 normal schools and training colleges for teachers, having 4,968 students. There are 10 other such institutions supported by non-public funds. The number of elementary schools in operation this year is 25,491, with 1,074,559 pupils.

SOCIETIES AND ACADEMIES
LONDON

which the greatest part of the Berlin press has assumed with regard to the doctrine of evolution must be attributed to this authority. But much as we must regret the reactionary current in this and other intelligent Berlin circles, yet we must point out that by this evil we are guarded from a far greater one. This greater, indeed the greatest, evil which could befall German science would be a Berlin monopoly of knowledge,' the centralisation of science. What highly disastrous fruit this centralisation has borne in France, for instance; how the Paris monopoly of knowledge' causes a constant degradation of French science, and has led it downwards from the greatest heights for the last half-century, is well known. Probably the wide-spread differentiation and the many-sided individuality of Royal Society, December 5.-"On the Illumination of the German national spirit, the often-decried German particu-Lines of Molecular Pressure, and the Trajectory of Molecules," larism, will save us from a centralisation of science of this kind, by William Crookes, F.R.S., V.P.C.S. which particularly in our capital, Berlin, would be doubly dangerous. Little as our 'small states' could be politically of any duration or could lead to a useful state-form, they have certainly been most beneficial and fertile for German science. Because this owes its principal advantages over others to the numerous little centres of education, which the capitals of the German small states formed, and to the many little universities which were always in healthy competition with one another. Let us hope that this beneficial decentralisation of science in our politically united Fatherland will continue permanently. Next to the centrifugal striving of our German national spirit, nothing will further this object so much as an energetic resistance to the free progress of science, just as now again it begins to show itself in the capital of the empire. Because at the same rate as this will remain behind in the mighty current of free and unimpeded mental progress, other numerous centres of education in Germany which follow this current enthusiastically, or at least willingly, will outrun it."

Induction Spark through Rarefied Gases. Dark Space round the Negative Pole

The author has examined the dark space which appears round the negative pole of an ordinary vacuum tube when the spark from an induction coil is passed through it. He describes many experiments with different kinds of poles, a varying intensity of spark, and different gases, and arrives at the following propo| sitions :Illumination of Lines of Molecular Pressure

a. Setting up an intense molecular vibration in a disk of metal by electrical means excites a molecular disturbance which affects the surface of the disk and the surrounding gas. With a dense gas the disturbance extends a short distance only from the metal; but as rarefaction continues, the layer of molecular disturbance increases in thickness. In air at a pressure of '078 mm. this molecular disturbance extends for at least 8 mm, from the surface of the disk, forming an oblate spheroid around it.

b. The diameter of this dark space varies with the exhaustion; with the kind of gas in which it is produced; with the temperature of the negative pole; and, in a slight degree, with the

"If Emil Dubois Reymond wanted to make his 'Ignorabi mus' the watchword of science, and Rudolf Virchow his still further-reaching 'Restringamur,' then from Jena and from a hundred other educational centres they are met with the call-intensity of the spark. For equal degrees of exhaustion it is greatest in hydrogen and least in carbonic acid, as compared with air.

"Impavidi progrediamur!"

UNIVERSITY AND EDUCATIONAL
INTELLIGENCE

STUDENTS of Natural Science who would much rather know French and German than Greek will be glad to learn that a very strong memorial against the retention of Greek as a subject for all honour candidates has been presented to Cambridge University. It is signed by ten heads of public schools, including Drs. Hornby (Eton), Butler (Harrow), and Abbott (City of London), Messrs. Matthew Arnold, Carlyle, W. E. Forster, the Bishops of Exeter and Manchester, Dean Cowie, Dean Stanley, and Dr. Vaughan, Prof. Jebb, and Mr. Roby, to say nothing of such bulwarks of science as Mr. Darwin, Prof. Huxley, Sir Joseph Hooker, Mr. Spottiswoode, and Prof. Tyndall.

THE Board of Musical Studies at Cambridge have applied for the appointment of a University Reader in Acoustics.

THE Sum in the hands of the Sedgwick Memorial Committee for the erection of a new building for the geological collection is 12,000/., not 1,200/. as we stated last week.

King's College (London) Magazine, No. 5, vol. ii. of which has been sent us, contains some pleasant reading, but no one would infer from its contents that the College was an important centre of scientific instruction and research.

DR. J. COSSAR EWART has been appointed by the Crown to the Chair of Natural History in the University of Aberdeen.

MR. F. GUTHRIE, formerly of Graaf-Reinet College, has been appointed to the Chair of Mathematics at the South African College, Capetown.

THE Journal de St. Pétersbourg gives the following particulars concerning the public provision for education in Russia :-The sum assigned in the Budget of this year for education is 15,971,289 roubles (about 2,395,000l.). There are eight Universities (not reckoning that of Helsingfors for Finland), with 5,629 students. Of these 85 are divinity students, 583 belong to the philological faculty, 1,629 to the faculty of law, 30 to that of Eastern languages, 622 to the mathematical faculty, 550 to that of natural science, and 2,130 to the medical faculty. There are 53 ecclesiastical seminaries, with 12,227 pupils; 195 gymnasia and pro-gymnasia, with 50,701 pupils; 56 middleclass schools, with 10,888 scholars. There are 19 military

c. The shape and size of this dark space do not vary with the distance separating the poles; nor, only very slightly, with alteration of battery power; nor with intensity of spark. When the power is great the brilliancy of the unoccupied parts of the tube overpowers the dark space, rendering it difficult of observation; but, on careful scrutiny, it may still be seen unchanged in size, nor does it alter even when, with a very faint spark, it is scarcely visible. On still further reduction of the power, it fades entirely away, but without change of form.

The author describes numerous experiments, devised to ascertain if this visible layer of molecular disturbance is identical with the invisible layer of molecular pressure or stress, the investigation of which has occupied him for some years.

The Electrical Radiometer

One of these experiments is as follows:-An ordinary radiometer is made, with aluminium disks for vanes, each disk coated with a film of mica. The fly is supported by a hard steel cup instead of a glass cup, and the needle point on which it works is connected by means of a wire with a platinum terminal sealed into the glass. At the top of the radiometer bulb a second

terminal is sealed in. The radiometer can therefore be connected with an induction coil, the movable fly being made the negative pole.

Passing over the phenomena observed at low exhaustions, the author finds that, when connected with the coil, a halo of a velvety violet light forms on the metallic side of the vanes, the mica side remaining dark throughout these experiments. As the pressure diminishes a dark space is seen to separate the violet halo from the metal. At a pressure of half a millimetre this dark space extends to the glass, and positive rotation commences. On continuing the exhaustion the dark space further widens out and appears to flatten itself against the glass, and the rotation becomes very rapid.

When aluminium cups are used for the vanes, instead of disks backed with mica, similar appearances are seen. The velvety violet halo forms over each side of the cup. On increasing the exhaustion the dark space widens out, retaining almost exactly the shape of the cup. The bright margin of the dark space becomes concentrated at the concave side of the cup to a luminous focus, and widens out at the convex side. On further exhaustion the dark space on the convex side touches the glass,