instrumentality, we are informed, the knowledge of the rotation of crops was introduced into districts where rotation cropping had been previously unknown, and where the potato and oats were the only crops formerly cultivated. Before embarking in any scheme of agricultural education, the people of Victoria would do well to study the "ups " and "downs" of this Irish system, which has been in operation for upwards of thirty years, and which, if report be true, is about being freely pruned by the Treasury. This Irish system of agricultural education is directed by a body of twenty Commissioners, of whom one is a paid administrator, nineteen being unpaid. We take it for granted that they and the Government of the day concur in the action of the Treasury. There is a widespread feeling that there are, or have been, men at the Treasury who are opposed to public grants for agricultural education, and who say there is no reason why farmers should be taught their business any more than shoemakers or carpenters.

But all that the best friends of agricultural education

claim is, that the fundamental truths of agricultural sci

ence should be taught in our rural schools, and that there should be a few normal schools or colleges in which the best minds of the country could be thoroughly educated in the science of agriculture, so as to qualify them for making investigations, and for taking a leading part in agricultural progress. This is, according to our interpretation, all that the Secretary of the Agricultural Department of Victoria asks; and we trust the Government of Victoria will carry out his views. If they carefully study the several sides of the Irish system, they cannot fail to devise a system of agricultural education which would confer lasting benefits on the colony.

It has been already stated that Mr. Ivey contributes two papers, one on Chemistry and the other on the State Forests. It is not often that a man professes chemistry and forestry. Many a chemist is also a naturalist, and why should not a man study the habits of forest trees as well as those branches of knowledge included in natural history? Mr. Ivey's report on the forests is interesting, but his chemical report concerns us more. He gives us several chemical analyses of virgin soils, and endeavours to show that such analyses are of direct use to the farmer. We agree with Mr. Ivey when he says that the chemist, by discovering some compound in the soil unfavourable to crops, can afford the settler information which will save him from the loss of pitching his tent on a barren location. We must, however, assure Mr. Ivey that he pushes a little too far his argument in favour of the value of chemical analyses of soil. We have now before us a most remarkable sheet, drawn up by an advanced agriculturist, in which appear thirteen chemical analyses of soils and subsoils, and the rents of these soils, and we must say that we have never seen any return showing a great discordance between the indications of analyses and the judgment of men who know to a shade the actual value of land. If Mr. Ivey is ambitious to make his investigations in this department of chemistry of real use and benefit to the farmer, he must strike out a new line of thought. Until he does this he should, if he would retain the good opinion of men who are competent to form a correct estimate of his work, confine himself to those fields of labour in which there is

ample room for the application of the established principles of chemistry.

Mr. R. L. J. Ellery, F.R.S., Government Astronomer, contributes to the Report now under review an able and interesting report on the meteorology of Victoria. Many of the rising generation cast their thoughts on the colonies with a view to emigration; and to these Mr. Ellery's report must be instructive. In the following passage we get a general notion of the physical features of the country :

"By an examination of a contoured plan of the colony, we find that the most prominent feature is an extensive mountain range running approximately east and west, rising somewhat abruptly about lat. 37° 30′, and long. 141° 40', varying in altitude from 1,000 to 5,000 feet, and culminating in the N.E. in lat. 36° 30', long. 148° 20, at Mount Kosciusko, the highest part of Australian Alps, where it attains an altitude of over 7,000 feet. The higher parts of this range, are covered with snow for several months in the year. The mountain country is for the most part densely wooded with fine timber, even to the very summits; at some of the higher elevations, however, especially in the N.E., many of the peaks are quite bare, or only partially covered with dwarfed trees or shrubs. The country north and south of this great dividing range is moderately undulating or flat, consisting often of large plains, in some parts quite destitute of trees, but closely wooded in others. Along some parts of the coast-line, and Wilson's Promontory districts, the land rises to conhowever, especially in the Cape Otway, Western Port, siderable altitude (from 2,000 to 3,c00 feet) by ranges generally well covered by timber to their summits. On the whole, the country is not well watered; the rivers are few and insignificant and are often nearly dry in summer; there are several lakes, both salt and fresh, in different parts, but not of sufficient extent to have any marked influence on the climate. The coast-line itself is for the most part flat, with a moderate elevation; although, as just stated, at some places lofty ranges abut on the sea, and the coast becomes precipitous and rugged. An extensive sea-board, open to polar winds and oceanic currents, modified, no doubt, by the presence of the island of Tasmania, an extensive and wooded mountain range running across the whole breadth of the colony, the higher portions of which are often clothed in snow, and the generally arid sub-tropical Australian interior, dominating on its northern and western boundary, must each necessarily exercise considerable influence in producing conditions of climate varying with the locality."

The notion is generally entertained in these countries that the climate of Victoria is extremely dry. Mr. Ellery shows that the rainfall attains to the average of similar latitudes in other parts of the globe. He puts the average at 25.66 inches per annum. Spontaneous evaporation is, however, very great; and a large quantity of the rainfall is also lost in consequence of the vast area of the country which has been unbroken.

The mean temperature of the year is given as follows:-
Melbourne
Bush Waste
Stawell

Portland. Cape Otway Port Albert Saba Island. Ararat. Ballarat Sandhurst

57°5

57°2

60°9

57°.7

57°.I

56°4

53°.I

58°.6

Heathcote

57°4

580

56°2

53°6

Camperdown

54°6

5807

The minimum of heat occurs in June, July, and August. The lowest known at Melbourne is 27°, or 5° below the freezing-point; at Portland, 27°; at Sandhurst, 27°5, and at Ballarat, 22°.

The highest recorded temperature in the shade occurs at Sandhurst in January, and was 117°; at Melbourne III°. "There are other localities in which higher temperatures prevail in the same month, especially in the plains north of the dividing range, and along the banks of the Murray, in which the temperature has been as high as 123° to 125° for several days together. It is during the hot winds to which the climate is subject in summer that our highest temperatures occur, but they seldom last many hours, and are usually followed by a change in the direction of the wind, and by a comparatively low thermometer, when a fall of 20° to 25° often occurs in as many minutes." We intended to make some remarks on the general advantages of a Department of Agriculture, but shall reserve them for a review of a similar volume which has come to us from the United States of America.

OUR BOOK SHELF

The Pathological Significance of Nematode Hæmatozoa. By T. R. Lewis, M.B., Staff-Surgeon H.M.B.F., on Special Duty. (Calcutta: 1874).

THIS little work may be regarded as a companion volume to Dr. Lewis's essay "On a Hæmatozoon in Human Blood.” Both are reprints from the Annual Reports of the Sanitary Commissioner with the Government of India, for the years 1871 and 1873 respectively, and as such testify to the high class of scientific labour performed by the staff officers on special duty.

The main points brought out by Dr. Lewis are such as afford proof that chyluria (or a milky-looking condition of the urine) and the elephantoid state of the tissues are associated with the presence of a microscopic nematode entozoon in the human blood. Having fairly established that conclusion, he next proceeds to show that the disorders in question are immediately "due to the mechanical interruption to the flow of the nutritive fluid in the capillaries and lymphatics." No one who takes the trouble to look into the evidence so carefully collected by the author can fail to see that he has thrown a great deal of light upon the pathology of chyluria, elephantiasis, and other more or less closely allied morbid conditions; but Dr. Lewis has done more than this, for he has extended our knowledge of the habits and genetic relations of the microscopic hæmatozoa of the dog (so long a puzzle to helminthologists), and has shown that the so-called Filariæ sanguinis hominis are perfectly distinct from the canine filaria, which latter, moreover, he proves to be the progeny of the Filaria sanguinolenta. Further than this, the author has detected numerous specimens of an aberrant type of nematode worm in the walls of the stomach of pariah dogs. These parasites occupy small tumours, two or more being usually coiled together in the centre of each swelling. He speaks of them as Echinorhynchi, which, indeed, they somewhat resemble; but it is quite clear from the very admirable figures accompanying the description, that the worms are not members of the order Acanthocephala. They are, in fact, examples of the Cheiracanthus robustus hitherto found only in various species of Felis. The illustrations, throughout, are remarkably clear, and show the internal structure of the parasites to perfection. T. S. COBBOLD

LETTERS TO THE EDITOR [The Editor does not hold himself responsible for opinions expressed by his correspondents. Neither can he undertake to return, or to correspond with the writers of, rejected manuscripts. No notice is taken of anonymous communications.]

The Origin of the Jewish Week

MR. R. A. PROCTOR's paper on "Saturn and the Sabbath of the Jews," in the Contemporary Review of this month, reopens

one of the oldest and most interesting questions in the history of astronomy. Unfortunately, the writer is very imperfectly ac has, I think, imported not a little confusion into the discussion. quainted with the literature of his subject, and in consequence That the week of seven days is directly connected with the worship of the seven planets known to the ancients, is a theory which has always had many supporters. It is at once suggested proved if we could show that these names are as old as the by the familiar names of the seven days, and would be absolutely division of the lunar month into four weeks. Again, it is also a well-known, though less wide-spread doctrine, that the Jewish Sabbath passed into Mosaism from an earlier planetary religion. Of course, if it can be shown that the Sabbath was originally sacred to Saturn, we have a strong proof of the antiquity of the names of the week days, and a probability that these names are as old as the seven day week itself. In this way a question in the history of Semitic religions comes to have an important bearing on a question in the history of astronomy. Mr. Proctor reverses the argument. He assumes that we have the clearest possible evidence that all nations that adopted the seven-day week named the days after the planets, and did so in that peculiar order which is generally explained by assuming that a new planet presides over every successive hour of the week, and that each day takes the name of the planet of its first hour. It is then argued that Saturn, as the highest planet, was the supreme god of Assyria, and so also of the Egyptians who received their astrological lore from Chaldea. The Egyptians, we are told, certainly consecrated the seventh day of the week to Saturn, and since the Israelites left Egypt observing the Sabbath, while there is no evidence of a Sabbath in patriarchal times, "it is presumable that this day was a day of rest in Egypt." Now, whatever may be the ulti-. mate solution of the problem of the origin and diffusion of the seven-day week, this theory rests partly on uncertain assump tions, partly on undoubted blunders. It is notorious that several Semitic nations, not to speak of the Peruvians, had a seven-day week without planetary names; so that Mr. Proctor's fundamental assumption begs the whole question. Then, again, it is the opinion of so great an authority as Lepsius that the Egyptians had no seven-day week, but divided the month into three decades. The passage of Dion Cassius from which the contrary opinion is drawn is certainly not decisive for ancient Egyptian usage, and Mr. Proctor seems to quote his author at second hand; for he asserts, in flat contradiction to Dion, that when the latter wrote, neither Greeks nor Romans used the week. For the supposition that Saturn was the supreme god of the Egyptians, not a shadow of proof is offered, while what is said of the Assyrian Saturn is directly in the teeth of the most recent researches. If Mr. Proctor had read Schrader's essay on the Babylonian origin of the week, he would have known that Adar or Saturn is quite distinct from the supreme god Asur, Thus, apart from the late and doubtful testimony of Dion, Mr. Proctor has no other evidence for his Egyptian theory of the week than that which he derives from the presumed non-existence of the Sabbath among the Hebrews before they entered Egypt. But the seven-day week appears in the narrative of the flood, which is certainly not an Egyptian legend. I say nothing of numerous minor inaccuracies in Mr. Proctor's paper, but repeat that the point. on which new light requires to be thrown is whether it can be made out that the names of the seven days are as old as the week itself. This again seems to depend partly on the question whether the division of the day into twenty-four hours is older than the week, and partly on what can be determined as to early Egyptian and Chaldean subdivisions of the month. The Egyptians had a day of twenty-four hours, but had they a week? The Chaldeans may have had the week, but they seem to have divided the day (including the night) into twelve hours. Perhaps, however, it ought to be borne in mind that Dion gives another way of accounting for the names of the day, depending not on the division of the day into hours, but on the analogy of musical harmony (ἡ ἁρμονία ἡ διὰ τεσσάρων). The Jewish Sabbath can contribute little to the argument unless one is prepared with Lagarde to maintain that Shabbat is a name of Saturn. W. R. SMITH

Kirkes' Physiology

I HAVE observed in your issue of Jan. 28 (vol. xi. p. 248) a letter in answer to some previous remarks of mine concerning the true function of the sinuses of Valsalva. Your correspondent, Mr. Prideaux, does not, it seems, quarrel with the actual method of my reasoning, but urges that the conditions necessary for the

existence of the premisses do not practically obtain. I may remark, however, that Mr. Prideaux does not show how or in what manner my arguments are inapplicable, but contents himself with pointing out what he imagines to be an error in my conception of the mechanism of the part in question. Now, I candidly confess that my knowledge of the state of things at the base of the aorta was not based upon practical observation, but at the same time I must, in justice to myself, say that in the mental review which I took of the possibilities of construction of the valves, I recognised the probable existence of the case which forms the subject of Mr. Prideaux's demonstration. But as he seems to think that if this error be granted the whole reasoning which follows is consequently invalid, I assert that it is by no means obviously certain, à priori, that an alteration in the conditions of its application must necessarily modify the conclusion. On the contrary, this very point which he deems it needless to prove because he has no doubt that it will be allowed, is the very point on which the whole question turns. I think also that in the further illustration of this I shall be able to show that Mr. Prideaux has missed the sole idea for which I was anxious to contend, viz., "that no mechanical advantage is gained by the expansion of the aorta towards its termination." Moreover, if I can point out the occasion of his difference from myself, I shall at the same time be rendering my own assurance the more complete.

In the first place, then, I think the difference is more verbal than real, and depends upon a certain ambiguity in the term "force of reflux." This I have interpreted to mean the pressure which would be represented by an area equal to the normal calibre of the vessel, being of opinion that it cannot naturally be applied to the multiplied pressure which would be given by taking the total area of expansion as its equivalent. The former pressure is transmitted without diminution to the unsupported area of the valves.

Again, the statement that "owing to the expansion of the aorta towards its termination, the force of reflux is most efficiently sustained by the muscular substance of the ventricle," is undoubtedly true in one sense; but in this case it is reduced to a mere truism, and amounts simply to this, that "the muscular substance of the ventricle being partially exposed to the contact of the column of blood, the latter rests upon it," and this, indeed, holds good whether the valves be mediate between the blood and the structure of the ventricle or not. However, I cannot help crediting the enunciation of Mr. Savory's theory with more than this, and maintain that it naturally induces the idea that the arrangement is in some way advantageous to the valves, i.e., that the pressure is lessened on the unsupported portion.

That this conclusion was contrary to mechanical laws was what I endeavoured to show in my first letter, and that my arguments are equally applicable in the present instance is evident from the fact that the existence of that portion of the valves which rests upon the ventricle is mechanically unimportant and need not be considered, since the remainder of their surface bears just the same pressure as if they were attached directly to the margin of the ventricular ring.

It is possible, however, to make one other supposition on behalf of Mr. Savory's theory, that the error lies in its statement, and not in the theory itself. If this be the case it would at any rate be much better expressed thus: "That though the aorta expands towards its termination, the increase of pressure which the valves would thus have to bear is compensated by the support which they receive from the muscular substance of the ventricle."

With regard to the last paragraph of your correspondent's letter, in which he denies the possibility of contraction of the aortic orifice during the diastole, I can only say that instead of imagining this to be the case, I expressed a strong doubt as to its occurrence. For the original statement the text-book and not myself is responsible, as may be seen from the following quotation: "The reflux of blood is most efficiently sustained by the ventricular wall, which at the moment of its occurrence is probably in a state of contraction." That this, however, should take place is, as Mr. Prideaux justly observes, an impossibility, and only proves the existence of another error either of theory or enunciation. W. PERCY ASHE

51, Palace Gardens Terrace

Flight of Birds

THE Duke of Argyll appears to maintain that a bird can remain at rest in a uniform horizontal current by simply

placing and maintaining itself in a certain fixed attitude. He seems likewise to think that the muscular effort required to maintain this attitude is somehow an explanation of the pheno

menon.

But would a dead bird, of precisely the same weight, size, shape, &c., rigidly fixed in the same attitude, also remain poised under like conditions? Of course I do not refer to the practical difficulty of maintaining an exact balance in the case of a dead bird, but in order to test the theory I suppose a mathematically uniform current and a mathematically perfect poise.

The live bird being perfectly motionless, the two would be precisely in the same mechanical condition, although the rigid attitude of the live bird would be maintained by dint of muscular exertion, and that of the dead bird by rigor mortis. Under these circumstances, would the dead bird fall to the ground or remain poised? If the former, what mechanical forces would apply to it which do not apply to the live bird? If the latter, then it would clearly follow that both birds could without change of attitude move with a uniform velocity, in a horizontal line, through still air; for it is clear that the mechanical problem is precisely the same, whether the air be in motion and the bird at rest, or the bird in motion and the air at rest. In each case the relative motion is the same.

Suppose, for example, a bird were poised at rest in a westerly breeze, moving over the earth's surface at the rate of twelve miles an hour, and suppose also the surface of the earth on account of latitude to be moving at an equal rate in the opposite direction. To anyone stationed on the surface of the earth this would be a case of the bird remaining still in a moving current. Yet, in fact, the bird would really be moving through still air at the same rate as the surface of the earth. This, I think, will be sufficient to illustrate the fact that the motionless poising of a bird in a uniform current is identical with its uniform motion through still air without change of attitude.

I need hardly point out that the muscular effort necessary to maintain the required attitude, producing no actual motion, can do no mechanical work. It cannot overcome atmospheric friction, nor the effect of the attraction of the earth.

Perhaps, indeed, the following simple way of viewing the subject may render it still more obvious:

1. If the bird were deprived of its motor weight, i.e. if it were exactly of the weight of the atmosphere, then, whatever might be its motionless attitude, it would clearly float away like a balloon with the atmospheric current in which it was immersed.

2. If the air were at rest, then also under the same circumstances it must necessarily fall towards the ground, either vertically or obliquely, owing to its weight.

3. Therefore, by the most elementary law of the composition of motions, it follows that, taking into account the weight of the bird and the motion of the atmosphere, the actual resultant motion will be a motion combined of a motion vertically downwards and one or more horizontal motions.

4. The resistance of the air on the relatively still wings of the bird enables it to convert its downward motion partially into a forward motion also; but it is quite obvious that a motion combined of horizontal motions and a downward motion must result in a downward motion, and cannot produce equilibrium.

The Duke of Argyll's testimony to the fact that birds hover apparently without motion in horizontal air currents is valuable, and no doubt increases the difficulty of accounting for the phenomenon on the hypothesis of upward currents. Graaf Reinet College

F. GUTHRIE

To Microscopists and Entomologists CAN any of your readers who are microscopists and entomologists help me to a successful method of killing and mounting Hoplophora decumana-belonging to the order Acarina?

The difficulties it presents are, that on being touched it contracts its head and legs and withdraws them into the horny envelope which surrounds its body, and that portion of the envelope extending over the head then closes tightly upon the aperture, completely shutting in the head and legs, so that in this condition the creature appears like a very minute seed covered with a few spinous projections. I can find no certain method of causing it to die unclosed, or so to mount it as to exhibit its form; and as the creature is not easily met with, I shall feel much indebted by any suggestions. I may add that I have consulted experienced mounters without success. Hill Top, Midhurst, Feb. 22 R. C. FISHER

* See NATURE, vol. x. p. 262.

"Chameleon Barometer"

IN my first communication (vol. xi. p. 307) upon this subject, I stated that the actual temperature had apparently no effect upon the colour of the paper. Since then I have had reason to change my opinion. During the late severe weather I have had better opportunities of studying the behaviour during frost, and I have observed that though in summer the paper will remain red for a difference of 3° between the thermometers, in very cold weather it is only red when that difference falls to o°, or perhaps 5o. This seems to agree with the fact that cold air cannot dissolve so much aqueous vapour as warm air. A. PERCY SMITH

Rugby, March 6

OUR ASTRONOMICAL COLUMN TOTAL SOLAR ECLIPSE OF 878, OCTOBER 29.-In a communication to the Times in August 1872, this eclipse, in the days of King Alfred, was pointed out by the Rev. S. J. Johnson, of Upton Helions, Devon, as having been probably total in London. In the Saxon Chronicle it is merely stated that "the sun was eclipsed one hour of the day," without reference to any phenomena of totality; the Chronicon_Scotorum records "a dark noon;" in the Annales Fuldenses we read: "Sol quoque in 4 Kal. Novembris post horam nonam ita obscuratus est per dimidiam horam, ut stellæ in cœlo apparent et omnenoctem sibi imminere putarent." This night-like appears ance of nature clearly indicates that the eclipse was total at Fulda (Hesse-Cassel), and if our calculations assign elements for the eclipse, which show totality. at this spot, it may fairly be assumed that they will give very nearly the true phase for London. Correcting the arguments of Damoiseau's Lunar Tables of 1824, so as to bring them into agreement with Hansen for moon and Le Verrier for sun, and taking the minor equations from the Tables, we find the following elements for 878, Oct. 29 :— Conjunction in R.A., oh. 51m. 245. M. T. at Greenwich.

Assuming the position of Fulda to be in longitude oh. 38m. 41s. E., and latitude 50° 33'7, we find by direct calculation from the above elements a total eclipse, totality commencing at 2h. 9m. 32s. local mean time, and

continuing im. 415. with the sun at an altitude of 19°. The partial phase began at oh. 56m. and ended at 3h. 24m. The Fulda annalist has " horam nonam post for the time of the eclipse, but the times we have found cannot be very much in error. The sun rose at Fulda on this day at 7h. 12m. apparent time, or at 6h. 57m. mean time, so that the ninth hour from sunrise would be 4 P.M. To reconcile this difference, Dr. Hartwig, of Leipsic (who calculated the eclipse in 1853 from the best data then available, without finding it quite total at Fulda), conjectured that the author of the Chronicle might have reckoned his time from the commencement of twilight at the beginning of the month. However this may be, our elements, which may be expected to be pretty near the truth, have indicated a very measurable duration of tctality at Fulda. Calculating now for London (St. Paul's), we again find a total eclipse commencing at 1h. 16m. 20s. mean time, and ending at 1h. 18m. 1os., or with a duration of im. 50s. If any reader should have the curiosity to examine the track of totality further, the following formulæ will assist

him. Putting for the geocentric latitude of place, and L for its longitude from Greenwich, reckoned positive eastward, t for Greenwich mean time

Cos. w=136'55co - [2'13760] sin. +[1°70924] cos. 7, cos. (L + 155° 31'7) t=1h. 17m. 155. [176081] sin. w- [3'32433] sin. - [3 91281j cos. 7, cos. (+ 109° 10''4) Upper sign for beginning of totality, lower one for ending; the quantities within the brackets are logarithms.

The Rev. S. J. Johnson found no other total eclipse in London during the long interval from 878 to 1715, and we are able to confirm his inference that there is not likely to be another one visible in the metropolis for five hundred years from the present time. Less than seven years after the eclipse of 878, or on June 16, 885, a very great eclipse passed over Scotland and Ireland. By a similar accurate computation to that detailed above, it is found to have been total not far from Nairn, and the duration of totality was little less than five minutes, a most unusual length for so high a latitude. In Chronicon Scotorum we read, “ The stars were seen in heavens."

Encke's ComeT.-The ephemeris of this comet for the present appearance, communicated by Dr. von Asten, of Pulkova, to the St. Petersburg Academy, not having been yet transferred to the Astronomische Nachrichten, where such matters are commonly looked for, we continue our reduction of the places to 8 P.M. Greenwich time for the period when the comet is likely to be most easily found in these latitudes:

March 20

I 25 58

74 32.8

74 6.7

I'350

The distance from the earth is expressed, as usual, in parts of the earth's mean distance from the sun.

VARIABLE STARS.--Next week we shall give the times of maxima and minima of the better known variable stars for two or three months in advance, calculated from the elements in Prof. Schönfeld's last catalogue. It does not appear that an ephemeris for 1875 has been circulated as in several previous years.

THE FRENCH TRANSIT EXPEDITION TO

NEW CALEDONIA

WE have received the following interesting communi

cation from a correspondent :

The French Transit of Venus Expedition to New Caledonia was the result of an after-thought on the part of the French Academy, which only took a definite form in the shape of active preparations for the great event in May last, months, if not years, after the other stations had been fixed on and the construction of the necessary instruments commenced. The New Caledonian observers were consequently at a great disadvantage, being obliged to complete all their arrangements within the short space of ten weeks, and to start for this Ultima Thule of civilisation in the middle of July. Everything, however, was got in readiness at home with so much care and despatch that nothing of the slightest importance, either in the astronomical or photographic department of the expedition, has been found wanting. The observatory has been fitted up and the observations made with as much completeness as if the centre of France, and not a convict settlement at the very opposite extremity of the

world, had been the scene of operations, and the results, though not all that could be desired, are nevertheless well worthy of the time and money expended in obtaining them.

M. Andrè, of the Paris Observatory, a well-known French astronomer, was appointed director of the expedition, whilst to M. Angot, Professor of Physics in the Normal School, Paris, the photographic portion of the work was entrusted. The instruments to be used consisted of five telescopes of various powers; a very complete photographic apparatus which will be described hereafter; a meridian instrument; an apparatus for producing an artificial transit, with electric chronograph carrying four pens attached; and lastly, two instruments for accurately determining the magnetic inclination and declination of Nouméa, which up to the present time have never been exactly known. The largest of the telescopes (7.5 in.), as well as three others (5 in.), was provided with an objective silvered by M. Foucault's process, the fifth having an unsilvered lens of 3 in. diameter, and of extremely good definition. All the instruments were equatorially mounted, three of them being connected with the chronograph, whilst the other two obtained their time by means of clock and chronometer. The telescope used for the photographic part of the work had an objective of 5 in. diameter and 13 ft. focal length, and was firmly fixed in a horizontal position on stone pillars, the image of the sun being directed along the axis by a large silvered mirror placed outside and moved at will from the interior by means of long wooden rods on either side of and parallel to the telescope. During the transit an assistant stood near this mirror, and at every command "Découvrez," removed the cover (placed on the mirror to prevent it becoming heated, and thereby causing distortion of the sun's image), and replaced it immediately after the plate had been exposed. With this apparatus, the daguerreotype process of sensitising a silvered plate of copper by means of iodine and bromine, developing in a mercury bath and fixing with hyposulphite of soda, was alone employed, and with the greatest success.

Though the day was somewhat cloudy, considerably over 100 very well-defined pictures of Venus during the Transit were obtained, together with 130 others, rendered less distinct by the intervention of clouds. When it is known that for several days previous to the 9th, the weather had been so bad that all hopes even of a glimpse of the transit of the planet were abandoned, and that dense clouds hung over the whole sky, and heavy showers of rain fell up to within four hours of the first contact, M. Angot may well be congratulated on the success of his labours. These daguerreotype pictures are not quite 1 in. in diameter, and were obtained by exposures of the plates varying from too of a second in duration. M. Janssen's method was not employed, but a very simple plan was adopted of placing the sensitised plate in a frame fixed at the focus of the chemical rays, and causing the exposure by sliding in front of it a metallic screen with a slit in it, whose width of course varied with the time necessary for exposure. A clock connected electrically with the sidereal one in the main observatory was placed in a convenient position above the telescope, and the instant of each exposure accurately noted. The assistants in this work, four in number, were all convicts, who performed their share with the neatness and readiness for which Frenchmen, whatever their position in life may be, are so remarkable; and, indeed, nothing has struck me more during the progress of the work here than the aptitude which seems innate in the French race for work of this kind; and it is no disparagement to English soldiers to say that it would have taken them days to learn to read chronometers with the accuracy which their French brethren-in-arms acquired in a few hours and apparently without the slightest difficulty. The main features in all the telescopic observations are the

33 minutes' difference between the estimated and observed times of first contact, the absence of the drop, and, in the case of the instruments furnished with silvered objectives, the clear tangential contact of the planet and the sun's limb, which enabled four out of the five observers to obtain the instant of second contact with very great accuracy. With these objectives, which appear to be especially well adapted for observations of this nature, the planet was seen to pass clear and distinct on to the sun's disc, without any appearance of distortion or cloudiness whatever; but with the unsilvered objective an appearance was observed as if a drop, such as those described by English astronomers, was about to form. Without forming, however, it changed almost imperceptibly into a tremulous haziness, which rendered it impossible to say when the actual contact took place, and compelled the observer to note two instants, one when this haziness first appeared, and the other when it had so far disappeared in the increasing brightness in the rear of the planet that he was confident that Venus was fairly on the solar disc. These two instants are separated by an interval of thirtyfour seconds, and their mean corresponds within two or three seconds with the instant of tangential contact observed with the other instruments. Whether the slight cloudiness of the sky, or a constant error peculiar to all unsilvered objectives, or the fact that the latter telescope was focussed on a spot much nearer to the sun's limb than the other instruments, is to be put down as the cause of this difference or not, seems at present a matter of doubt only to be cleared up when other observations with unsilvered lenses are recorded.

The third and most important contact in New Caledonia was not observed, owing to a cloud which, much to our chagrin, strayed over the sun's face some 6′ before the estimated time of egress, and completely shut out our view for about 20', after which the fourth contact was observed, but with a considerable degree of uncertainty, on account of the undulatory appearance of the sun's limb.

I may mention, in conclusion, that the times of duration of the whole transit, ie. the interval between the first and fourth contacts, obtained by three of the observers, differed by only 8", but these were considerably at variance with the estimated duration of the transit as given in the Nautical Almanac. Besides MM. Andrè and Angot, three French officers, Capts. Derbés, Bertin, Ribout, and Mr. Abbay, took part in the observations. A. On board the Rangatira, Jan. 5, 1875

SCIENTIFIC REPORT OF THE AUSTRO-HUNGARIAN NORTH POLAR EXPEDITION OF 1872-74 *

THE real object of the expedition was not particularly that of large unknown sea north of Siberia; the explorers thought they reaching high latitudes, but rather the investigation of the might eventually reach Behring's Straits, without cherishing very sanguine hopes on this point. When during 1871 Lieut. Weyprecht made a preliminary expedition into those regions, he found the whole large sea between East Spitzbergen and Nowaja Semlja so completely unknown, that in spite of his stopping six weeks at Tromsö, and making inquiries of all Finnmark skippers and whalers, he could not learn anything definite as to the conditions of climate and ice in those parts; few vessels had succeeded in reaching the 76th degree of north latitude. During the two Austrian expeditions this unknown sea has been investigated from 40° to 70° East long. (from Greenwich), and beyond the 79th degree of latitude on the west side and the Soth on the east side; an extensive, hitherto unknown tract of land has been discovered, and Lieut. Julius Payer has made sledge journeys into this land, reaching very nearly 83° N. lat.

In 1871 the explorers had found the sea completely free from * Die 2. Oesterr.-Ungarische Nord Polar Expedition unter Weyprecht und Payer, 1872-74. (Petermann's Geogr. Mittheilungen, 1875; heft ii.)