office of the Post Office telegraphs. In connection with this system, I would express the hope that the proposal to establish an hourly signal at the Start Point will be borne in mind.

"Last autumn a telegraphic determination of the longitude of Leiden was made with great care by M. M. Bakhuyzen. The interchange of signals between Greenwich and Leiden occupied nearly four months. I may here remark that the American extension of longitude carried out under Commander Green, U.S.N., to which reference was made in the last report, will be most useful for the transit of Venus in 1882. Cannot a British officer be found to complete the operations for Australia and New Zealand? I lament that this has not been done. Mr. Gill has undertaken the necessary work for the Cape."

The following important general remarks conclude the

report :

"The present meeting may afford a fitting opportunity for the expression of my views on the general objects of the Observatory, and on the duties which they impose on all who are actively concerned in its conduct. As suming as beyond dispute that these ought to be carried out in a spirit liberal in itself and honourable to the nation, I proceed to state my opinion on the line of action which they suggest.

"The object prescribed to the Observatory is the promotion of "Astronomy and Navigation." And, since the abolition of the Board of Longitude, the second of these objects (which historically gave rise to the introduction of the first) presses upon the directors of the Observatory much more strongly than before. Considering then the claims of astronomy as b aring on navigation and our responsibilities in reference to them, we find that those responsibilities are by no means narrow. Whatever the rest of the scientific world may do or may not do, we are responsible for determinations of the fundamental elements of sidereal, solar, and especially lunar astronomy, with the highest accuracy that modern skill can secure. The same apparatus of instruments and of mathematical treatment which fix the places of fundamental stars will apply to those of other stars; the same which apply to the sun will apply to planets and comets (not unconnected with solar theory, by virtue of perturbation) and even to satellites. And we could hardly consider ourselves as discharging our duty to the more educated portion of the nation, or as maintaining our proper position in the world, if we did not include in our operations these latter offshoots of the first-mentioned objects.

"But new astronomical subjects have arisen of which no one dreamed when our constitution was first fixed. The first of these was the measures of double stars. But this, though important as ever, has almost disappeared from our view when occupied with solar and spectroscopic physics. I yield to no one in the interest which I take in these subjects, and in the admiration with which I regard the positive conclusions and the problematic suggestions which are founded on them. But I still point out that these are not parts of our original system, and their connection with the Greenwich Observatory is at any time liable to question.

"I now advert to the general subject of navigation. And first I remark that magnetism, in its ordinary and nautical form, is indisputably a proper subject for the Observatory. But within the present century there have arisen :-the accurate examination of magnetic irregularities, the partial reduction of daily irregularities to practical laws (still wanting theoretical explanation), and the establishment of the simultaneous co-existence of occasional disturbances covering the whole surface of the earth. Connected with these is the observation of magnetic currents through the terrestrial soil, registered at Greenwich for many years past, and now attracting attention on the Continent. Perhaps no branch of physics bears the same prospective

importance as these. Yet I conceive that their continued study in this Observatory requires special authorisation. "The original views in making astronomy contributory to navigation were limited to observations of the moon. But in the latter part of the last century the possibility of making chronometers subservient to the determination of longitude (a subject to which the late Board of Longitude gave good attention, and to which the Government has always offered liberal rewards) was proved, and in the present century the improvement has been very great. This has been effected by our Hydrographical Office (mainly through the action of the Observatory), partly by specific rewards, partly by careful attention to the accuracy of every chronometer purchased. And the practical value of the chronometric system has been very greatly increased by taking advantage of the galvanic distribution of time currents, and by the galvanic exhibition of ball-drops and other signals. There can be no doubt that all the agencies involved in this system are well employed, and that they are a legitimate part of the Observatory duty as originally contemplated.

"Still I remark that the Observatory operations bearing on chronometric navigation are not carried out to the extent which I could desire. It is known to all persons familiar with chronometers that rates of the chronometers, obtained while the ships are actually in voyage, would possess remarkable value. We possess the power of giving facility for obtaining these to a large part of our mercantile navy, by exhibiting a time-signal at every hour, at Deal (where the necessary apparatus already exists) and on the Start Point. I have several times brought this proposal, as regards the Start, before the Government, but unsuccessfully. But I should have done wrong if I had omitted, in this general survey of the duties of the Observatory, to state my continued conviction that this is a proper and very desirable addition to the other points of assistance which we can give to navigation.

"Next-closely connected however with the subject of navigation is the knowledge of the longitudes of distant ports, as referred to the Greenwich Observatory. And I approach this subject with grief. We have entirely abandoned the longitudes of the Atlantic, which have been cleared away, before our eyes, by the scientific enterprise of another nation. The Pacific, bearing those vast and important colonies, almost entirely British, is equally neglected; though so much is ready that the mission of a single officer would quickly establish all. The same aspiring nation which has mastered the Atlantic is now bent (as I understand) on adding to its scientific dominion the Pacific. I think this is not honourable to our nation.

"There remains another subject, which occupies no small part of the force of the Observatory, and which I am unable to connect with either of the two great divisions to which I have alluded--the subject of meteorology. It is exceedingly popular in the country, perhaps because it requires little of expense or of science. It is also pursued at many foreign observatories, where vast numbers of observations are produced without attempt at classification or reduction. We at least are not amenable to this accusation, and may appeal to our reduction of more than twenty years' collected observations as giving matter of permanent interest to the more scientific meteorologist, and even to the geologist. Still I call attention to the fact that this is a subject which, though introduced mainly by myself, I regard as foreign to the original Astronomy and Navigation' of the Observatory.

"There is still a matter for consideration, not in our observations, but in the mechanism by which they are made available to the world-I mean our printing. I have repeatedly expressed my opinion that the extent of our printing is far too great: not in the full exhibition of reductions, but in the minute details of individual observations. There are printed every year more than 7000 transits or circle readings, each consisting of 6 or 7 indi

vidual readings, of which only the mean is useful. I do not believe that, since the year 1835 at least, any person in the world except ourselves has actually taken a mean. As each reading contains 3 or 4 figures, there are printed in each year something like 150,000 useless figures. Reliance must be placed somewhere on the skill and fidelity of the observer, and (considering the severity with which every figure of transit-wire and of circle microscope, and of their means, is examined here) this reliance may be placed at least as well on the means as on the originals. I have reason to think that the bulky volume of nearly 900 pages, might be reduced to about three-fifths of its present size by omitting those originals.

"I would submit for the consideration of the Board whether it might not be advantageous that they should hold a special meeting to consider the subjects which I have indicated. The length of time at an ordinary visitation, and the circumstances under which the Board meets, are not sufficiently favourable for the discussion of broad questions of Observatory policy."

HOLTZ'S ELECTRICAL SHADOWS

IN W. Holz of Berlin has lately brought to light the

N an extremely elegant series of researches Prof.

existence of a new class of electrical phenomena, to which their distinguished discoverer has assigned the name of Electric Shadow-figures. Though nearly six months have elapsed since they were described in the Proceedings of the Göttingen Gesellschaft der Wissenschaften, no detailed account of them has appeared in any English journal. Yet the shadow-figures are remarkably easy to produce, and the whole research is of extreme simplicity, as very little apparatus is required beyond the simplest odds and ends to be found in every physical laboratory, the only large instrument necessary being one of Holtz's electrical machines.

The fundamental arrangement is that shown in Fig. 1. From the discharging-rods of a Holtz machine the brass balls are removed. To the left rod there is attached in place of the ball a circular disk of some 10 to 20 centimetres diameter, having its front face either flat or slightly concave. To the right rod a point is fixed, and it is drawn back till from 6 to 15 centimetres distant from the disk. A piece of silk or satin of the same size as the front surface of the disk is laid upon it while the machine is in action, it adheres of itself to the surface, and the preparation is now complete. Before the silk is placed over the disk a small "brush" discharge of blueish light is all that can be distinguished at the point of the righthand discharging-rod : but this now changes to a very faintly glowing star. At the same moment the central region of the silk-covered disk exhibits a peculiar glimmering light over a well-defined circle. The utmost care is needed to shut out all extraneous light from the room, otherwise the delicate appearances which follow cannot be seen. It is upon this circular patch of feeble light that the shadow-figures are thrown. Its pale gleam becomes more vivid when the machine is more energetically worked it enlarges in area but diminishes in brightness as the point is drawn back from it, and contracts with an accompanying increase in brightness as the point is brought nearer. It is possible to obtain a similar glimmering surface also upon a large metal ball covered with silk and attached to the rod in place of the concave disk, or instead a screen made of two or three folds of silk stretched over an ebonite ring may be placed between the two discharging-rods, the ends of both being furnished with points. In each case it is important that the silk be without crease or wrinkle, otherwise an evenly illuminated disk of light will not be obtained.

If now a body of definite outline of form be interposed between the point and the disk, an electrical shadow of it will be cast upon the luminous circle. These shadows

are truly electrical, not optical, for all bodies do not cast them, and, more curious still, different bodies though of the same shape may cast differently shaped shadows. Conductors of electricity cast well-defined shadows, and so do semi-conductors, such as wood and cardboard. True insulators of small dimensions cast no shadows. The insulation or non-insulation of the conducting bodies makes no difference in their shadow-giving power. A cross cut out of cardboard casts (as in Fig. 1) a well-defined shadow at the centre of the field, but the exterior portions are somewhat hazy. An ebonite cross casts no shadow. A cross made up of two strips, one of cardboard, the

other of ebonite, fastened with shellac, casts only a single bar of shadow. Rings of tinfoil, cardboard, or wire also cast shadows. Such small objects are conveniently held by attaching them to the end of glass rods. The size of the shadows increases if the objects are displaced from their central position to right or left. A strip of card or thin metal casts the same shadow whether it be held broadside or edgeways in the field. A wire grating having 5 millimetres width between the bars obscures the field like an opaque body. Breathing on a strip of ebonite or glass renders its surface a feeble conductor, and it casts a transient shadow. A glass rod heated at one point casts a shadow at the heated point, the shadow dying out as the

FIG. 2.

screen.

uminous figure projected through aperture in cardboard rod cools. No shadow is cast by a conductor whose surface is completely covered by insulating material, such as a shellac-covered wire or a glass tube containing water, but dry externally. The smoke ascending from a cigar casts moving shadows upon the silken screen. If a small ball be fixed upon the left discharging-rod in place of the point the shadow on the silk is poor, but a second shadow is observed upon the surface of the ball, and this is excessively small, reminding one of the diminished erect virtual optical image in a small polished ball. This one experiment succeeds best if the ball be made the positive con

ductor. For the other experiments it makes little difference whether the electrification of the point be positive or negative, except that when the point is positively electrified the illuminated surface is a little larger than when negatively electrified. A larger disk of light can also be obtained by working the machine at a greater velocity, but at the same time the shadows are rather smaller.

Prof. Holtz has also obtained the inverse phenomenon of luminous-figures by two different means. If two pointed needles are fixed horizontally side by side upon the discharging rod opposite to the disk, there appears a vertical streak of light across the glimmering field. If the needles be replaced by a horizontal strip of metal with its edge directed toward the disk, a vertical bright streak is also produced. A short metallic tube affixed to the discharging rod produces on the disk a dark central spot surrounded by a nebulous bright ring. The second kind of luminous-figures is produced in the manner shown in Fig. 2, where a circular disk of metal or cardboard having a central aperture of recognisable form is interposed between the point and the screen. The result is a luminous image of the aperture which, though well-defined at the middle, is marred at the outer regions, the shadowed portions appearing to encroach more upon the illuminated parts as we pass to the peripheral region. The following experiment is curious :-If a square aperture be chosen, the luminous figure projected on to the silken surface shows well-defined corners; but if a small round disk of card be interposed between the discharging point and the square aperture the luminous square on the silken screen at once exhibits rounded corners.

Another interesting point connected with the shadowfigures is that they can be fixed in a temporary manner, like Lichtenberg's figures, by sifting upon the silken surface lycopodium-powder or other fine dust. This collects chiefly upon the contours of the figures, though under certain conditions the luminous and shadowed parts exhibit a contrasted density in the deposit of dust upon them. These dust-figures have an obvious relation with those obtained by Wiedemann from the discharge of Leyden jars through a pointed conductor against the surface of various bodies. It would be interesting to ascertain whether by this process also shadow-figures can be produced.

In explanation of these appearances Prof. Holtz propounds the view that they are due to a rectilinear discharge of electrified particles from the point of the discharging-rod, the discharge taking the general form of a cone, but in which the paths of the outermost particles diverge more widely as they approach the silken disk. The function of the silk he believes to be to retard the discharge, and thereby to increase the electric density on the point. The conducting bodies which are interposed in order to produce shadows act therefore by deflecting the flying particles from their path, either by absorbing or reflecting them. In many cases this action would appear to be a repulsion, since the shadows are always larger than the objects, and suffer more distortion by enlargement nearer the borders of the disk. To explain the production of the double shadows, the rather doubtful hypothesis is advanced that there is a rectilinear discharge of particles

in both directions at once.

Quite independently of these observations, the same kind of phenomena have been investigated in America by Messrs. Fine and Magie of the Green School of Science, Princetown, N.J. These experimenters were aware of the existence of shadows on the positive discharging knob, but believed that they were the first to discover the existence of a negative shadow. They found however that non-conductors cast the best shadows, and added the interesting observation that the lines of electrical action were deflected by the presence of a conducting body at the side of the field, and the form of the shadow Correspondingly altered. Negative shadows were also

observed, they remark, some years ago by Prof. C. A. Young.

These shadow-figures become doubly interesting when compared with the "molecular-shadows" obtained by Crookes from electric discharges in high vacua. Further experiments are probably needed before their precise nature is fully known. S. P. T.

BEN NEVIS OBSERVATORY. PROPOSAL was made a year or two ago to erect

A an observatory on the top of Ben Nevis for meteorological observations, but nothing was done owing to the want of the necessary funds. A committee has been formed, however, within the last few months for the purpose of raising a testimonial to Mr. David Hutchison, who did so much in opening up the West Highlands to tourists with his steamboats, and we observe that it is proposed that the testimonial take the shape of an observatory on the top of Ben Nevis. The committee is a large and influential one, and the proposed scheme has every appearance of being successfully carried out. In the meantime the Scottish Meteorological Society has commenced daily observations on Ben Nevis, which will be continued during the summer months-the Society having accepted a handsome offer by Mr. C. L. Wragge, who has had experience of such work, to climb to the top of Ben Nevis every morning in time to make observations there at 9 a.m. A complete set of the best instruments has been procured. The barometer (a Fortin), is an excellent instrument, and is constructed to read as low as 23.000 inches, in the procuring of which Mr. Scott of the Meteorological Office kindly gave his assistance. On Tuesday, May 31, Mr. Wragge, with Mr. Livingstone, of the Public Schools, and nine workmen ascended the mountain, and the instruments were fixed and secured in proper positions, and all, including the barometer, were found to be in good working order. The regular observations began on the following day, June 1, Mr. Wragge being at his post on the top of the Ben, 4406 feet above the sea, at 9 a.m. He remains an hour at the top, and makes three observations, viz. at 9, 9.30, and 10 a.m. Even during the stormy weather of Saturday last, the observations were made and the observer back to Fort William at 1.30 p.m., on which occasion the temperature at the top was as low as 28°*0.

Simultaneously with the Ben Nevis observations, a complete series of observations are also made near sealevel by Mrs. Wragge. These observations, together with the observations made at the neighbouring stations of Roy Bridge, Corran, Landale, Airds, Lismore, and Dalnaspidal (1450 feet above the sea), will give the data required in dealing with some of the more important problems in meteorology.

NOTES

tion of women, perhaps none has done better work during the AMONGST the few existing institutions for the higher educalast thirty years in a quiet, unobtrusive fashion than Bedford College, York Place. The recent action of London University in opening its degrees to women has given a fresh impetus to women's education; and Bedford College has set itself the task of providing the training for which London University offers only the test-a task in which it has already achieved such success as to give a sure promise of a brilliant future. The funds, however, at its disposal, derived mainly from the bequest of the late Mrs. Reid, prove inadequate to the strain thus put on its resources, and an appeal for support is now being circulated which deserves the attention of the friends of education. In that appeal details of the work and aim of the College will be found. Space will only allow us to add that subscriptions will

Tartars do, nor with the Nogaï, who are now, however, not numerous. After having measured the skulls of about 200 persons, he finds that the cephalic index is: 0908 for children from 4 to 7 years old, o'882 from 8 to 9 years, o'876 from 10 to 12 years, o'871 from 13 to 14 years, o 852 from 15 to 19 years, and o 845 from 20 to 23, being the average from 82 measurements. When discussing the figures received for 27 very pure representatives of Tartars, he shows that the maximum figures were, in four cases, from o 886 to o'903, and the minimum in two cases, o'789 and o'800; for the 21 others the index varies comparatively little, namely, from 0.822 to 0 876. M. Merejkoffsky has observed among the Tartar women the use of tattooing in small spots between the eyebrows and on the forehead. As to the staining the nails red, which is spread everywhere among the women, and sometimes also among men, M. Merejkoffsky, after having discussed the same custom among other peoples, arrives at the conclusion that it is a survival from the time when the whole skin was stained with red, originally with the blood of enemies, to inspire dread.

THE geysers of Whakarewarewa, New Zealand, are stated to have lately been in a state of agitation, throwing hot water to a great height. The natives anticipated still further eruptions. The geysers have been dormant for six months.

THE Annual Report for 1879-80 contained in the Proceedings of the Norwich Geological Society complains of the little interest taken in the work of the Society by the members; the bulk of the work seems to be done by the members of the Geological Survey stationed in the neighbourhood. The presidential address, by Mr. J. H. Blake, "On the Age and Relation of the so-called 'Forest-bed of the Norfolk and Suffolk Coast,'" is of considerable interest. It has been separately reprinted. Among the "The Subdivisions of the Chalk," by other papers is one on Mr. A. J. Jukes-Browne.

THE Twenty-Third Report of the East Kent Natural History Society contains some of the more important papers read during the year. We regret to see that the interest of some of the members in the welfare and work of the Society is not so great as it might be, and that, as in not a few similar societies, the bulk of the work falls on the shoulders of a few of the more energetic members.

WE are glad to find a decided improvement in No. 1, vol. x. of the Canadian Naturalist. The papers are mostly geological, a large proportion are original, or at least of purely Canadian origin, and all of scientific value. Principal Dawson contributes some important Palæontological Notes, and there is a long paper by Mr. R. Chalmers on the Glacial Phenomena of the Bay Chaleur Region, with a map. Dr. G. M. Dawson writes of the Geology of the Peace River Region. Appended are Meteorological Notes for 1880, and a curious statement as to the Niagara Falls having been dry for a day, March 31, 1848.

Natura Novitates, the fortnightly list of novelties in scientific literature, started some time ago by Friedländer of Berlin, continues, we are glad to see, to flourish. It is calculated to be of real service to workers in science.

MR. JOSCELINE BAGOT and Mr. Drummond, of the Grenadier Guards, accompanied by Mr. T. Wright, the winner of the International Balloon Contest, went up in a balloon from the Crystal Palace on the 1st inst. at I p.m. When the ropes were loosed they ascended to the height of 5000 feet, and travelled slowly in a south-westerly direction for the distance of about eight miles. The balloon then suddenly sank, but ballast being thrown out, it rose again to 8000 feet, and traversed in the direction of Epsom. The aeronauts then descended in a field about a quarter of a mile from the Grand Stand, which they reached n time to witness the race for the Derby.

SIR R. TEMPLE'S lecture on the lake region of Sikkim is given in the current issue of the Geographical Society's Proceedings, illustrated by a capital map and some very good engravings from the author's sketches on the spot. The other papers are a translation from the Russian by Mr. Delmar Morgan of Dr. Regel's account of his expedition from Kuldja to Turfan in 1879-80, and Mr. F. C. Selous' notes on recent explorations in Ma-huna-land, the latter of which adds something to our knowledge of the hydrography of the Zambesi basin, and is accompanied by a map in the text showing the routes of Mr. Selous and others. The geographical notes relate chiefly to the work of various expeditions on the Congo and other parts of West Africa. There are also notes of some interest on the true name of the Chukches and on Richmond Gulf, Hudson's Bay. Mr. James Stevenson contributes a memorandum of the longitude of Lake Nyassa, which is followed by a full abstract of the proceedings of the Paris and Berlin Geographical Societies.

THE paper by General Pitt-Rivers announced last week will be read at the Anthropological Institute on the 14th, not 7th

inst.

THE additions to the Zoological Society's Gardens during the past week include a Macaque Monkey (Macacus cynomolgus 8 ) from India, presented by Mr. W. Nugent; a Vulpine Phalanger (Phalangista vu'pina 8) from Australia, presented by Master H. Berridge; ten Green Lizards (Lacerta viridis), European, presented by Mr. H. N. Moseley, F.Z.S.; two Ostriches (Struthio camelus 89) from Africa, two White-backed Piping Crows (Gymnorhina leuconota), a Laughing Kingfisher (Dacelo gigantea) from South Australia, deposited; a Prince Albert's Curassow (Crax alberti ?) from Columbia, two Golden Agoutis (Dasyprocta aguti) from Guiana, two Common Boas (Boa constrictor) from South America, on approval; a Japanese Deer (Cervus sika 8), a Cuming's Octodon (Octodon cumingi), born in the Gardens; five Impeyan Pheasants (Lophophorus impeyanus), four Peacock Pheasants (Polyplectron chinquis), a Ruddy Sheldrake (Tadorna rutila), bred in the Gardens.

UNIVERSITY AND EDUCATIONAL
INTELLIGENCE

OXFORD-In a Convocation holden on June 7 a decree was passed, without opposition, to amend the statute relating to the Degree in Medicine. According to the new decree, those who enter their names for the First Examination for the Degree of Bachelor of Medicine, and who satisfy the Regius Professor of Medicine that they have obtained Honours in the School of Natural Science, or that they have passed the Preliminary Honour Examination in the same School, shall not be required to be examined either in Chemistry or in Mechanics and Physics at the First Examination for the Degree of Bachelor of Medicine.

In the same Convocation the statute to enable non-members of the University to pass an examination in lieu of Responsions was also passed without opposition. The first examination in lieu of Responsions will be held towards the end of the ensuing long vacation.

Mr. George B. Ferguson, M.D., Hertford College, has been nominated Examiner in the Natural Science School in place of Prof. Lankester, and Mr. John Watts, M.A., Balliol College, in place of Dr. Odling.

Prof. Sayce announces a public lecture in the Taylorian Institution, June 8, on the ancient Hebrew inscription recently discovered in Jerusalem.

An examination will be held in Exeter College early in October for the purpose of filling up a Natural Science Scholarship, tenable for four years during residence. The age of the Candidates is not limited, but they will be expected to give evidence of sufficient Classical knowledge to be able to pass Responsions. The examination will be in Biology, Chemistry, and Physics. Candidates will be expected to show proficiency in at least two of these subjects, and the Scholar will be