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admitted that this conclusion needs confirmation from The Gum-Bichromate Process. By J. Cruwys future discoveries before it can be definitely accepted. | Richards. Pp. 119. (London : Iliffe and Sons, The specimens on which the new genera Cory Ltd., n.d.) Price 25. 6d. net. phænopsis and Bayeria (Fritsch) are founded are | This process of photographic printing is about fifty certainly remarkable.

years old, but it is only during the last ten years or Dr. Fritsch's section of the work shows that all so that it has been adopted for practical purposes. the usual groups of Cretaceous Reptilia are repre When first introduced it was deliberately rejected, sented in the Bohemian rocks. There are undoubted because it was not equal to the then known processes fragments of Plesiosaurs, and there is one interest- in reproducing the detail of the negative; latterly it ing brain-cast which the author describes as probably has been taken up and very much appreciated by referable to Polyptychodon. Dr. Fritsch, however, some of those who desire to be able to alter or overlooks the fact that the skull of Polyptychodon is “ control” their photographic printing, and so obtain actually known in England, and is undoubtedly results that, while they can lay no claim to mechanical Plesiosaurian or Pliosaurian, not Mosasaurian. accuracy, more nearly please the æsthetic taste of Chelonian remains occur, evidently representing the worker. At the present time there are more turtles related to the small Chelone Benstedi from the methods of photographic printing than there were English Chalk. Some fragments appear to be a generation ago that are excellently adapted for the Mosasaurian, but those described under the new name purposes of photography pure and simple; therefore of Iserosaurus litoralis are extremely problematical. the gum-bichromate process is still more than it was Other fragments, ascribed without much reason to then a process for the specialist in the direction named. Dinosauria, scarcely suffice to justify the new names The author of this volume is well known as a bestowed on them. Some good new figures of the successful worker of the method. He gives his own interesting wing-bones of the small Pterodactyl, formulæ, and states clearly the practical details that Ornithocheirus hlavaci, are given, and the volume he prefers to follow, but he also describes the methods concludes with a systematic list of species.

of others. He is a warm advocate of “multiple A. S. W. printing"; that is, after coating the paper, exposing,

developing with warm water aided with a brush or Die Bedeutung des Experimentes für den Unterricht | by other mechanical means, coating, exposing, and

in der Chemie. By Dr. Max Wehner. Pp. 62. developing a second or even a third or more times, (Leipzig and Berlin: B. G. Teubner, 1905.) Price so gradually building up the picture with the maxi1.40 marks.

mum opportunity of control.” It will be obvious This brochure forms part of a “ Sammlung natur

that every possibility of improvement in the hands of wissenschaftlich-pädogogischer Abhandlungen,” and

the skilful is a probability of error in the hands of is very hard reading for an ordinary English chemist. the artistically ignorant, and that the process does not It is divided into two parts, the first of which deals

claim attention from a photographic point of view at with the importance of experiment for attaining

all, but as enabling an artist to express his ideas with the object of chemical instruction, and the second

less trouble and perhaps with more accurate drawing with the importance of experiment in relation to

than if he worked wholly by hand. The volume inmethod in chemical instruction. It is hard reading

cludes several reproductions of the author's works, in the sense that one has to wade through detailed

some of them showing the print in its various stages arguments which culminate in conclusions such as “ description does not suffice for the instruction of the pupil in chemical processes," and “the development of the law's concerning chemical processes from

LETTERS TO THE EDITOR. experimental observations is more effective for

[The Editor does not hold himself responsible for opinions chemical teaching than their deduction from quoted expressed by his correspondents. Neither can he undertake examples." The work is, in fact, an example of pure to return, or to correspond with the writers of, rejected pedagogical exercitation, and it may be recommended manuscripts intended for this or any other part of NATURE. with confidence only to those who have a liking for No notice is taken of anonymous communications.) that kind of literature.

Recent Changes in Vesuvius.

I beg to enclose a somewhat free translation of a letter Monographie des Cynipides d'Europe et dAlgérie.

I have recently received from Prof. G. Mercalli, of Naples, By l'Abbé J. J. Kieffer. Tome second. 2me. fasci

concerning certain changes which have taken place in cule. Pp. 289-748; plates ix-xxi. (Paris : A. Vesuvius this year. During a visit to the mountain on Hermann.) Price 18.

August 14-16, I was able to approach quite near to the This is the conclusion of vol. vii. bis of André's greats

sources of the lava streams described by him, and also to series of monographs, “Spécies des Hymenoptères,"

examine the remarkable tunnels formed at certain places and completes the Cynipides, or gall flies.

by the cooled surface of lava streams which had subThe pre

sequently diminished in volume, or had even “run dry." vious portions have already been noticed in NATURE

During the week preceding my visit, many incandescent (vol. lxvii. pp. 124-5, December 11, 1902, and vol

bombs of pasty rock had been ejected from the crater at Ixviii. p. 221, July 9, 1903), and the part now pub the summit, mostly in the direction of the side facing lished completes the Cynipides, 5e tribu, Figitinæ; Pompeii, and these successively rolling down the ash-slope and also includes the Evaniides (divided into two presented a beautiful spectacle at times. The lava streams tribes, Evaniinæ and Gasteruptioninæ), the Ste proper often presented that curious double appearance, due phanides, Trigonalides, Agriotypides, general supple

to the fact that the colder and darker scoriæ, floating ments, a Catalogue méthodique et synonymique,”

down the stream, keep to the more swiftly-moving current extending from pp. 653 to 741 (double columns), and

in mid-stream, and avoid the sides. general indices.

Yesternight (August 20) but one of the lava streams

referred to by Prof. Mercalli was visible from Naples, the The plan of the work is uniform throughout, and

other having apparently ceased. as the previous portions have already been discussed The explosions of Stromboli are occurring at intervals at considerable length, an extended notice is here of about 3} minutes.

R. T. GÜNTHER. unnecessary.

W. F. K. R.M.S. Oroya, off Stromboli, August 21.

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Lava Stream of May 27, 1905. In the months of April and May of this year Vesuvius began to show an increased activity, and in the crater, which was about 80 metres in depth, a small cone began to form ; it increased rapidly, and by the middle of May had risen to a height of about 15 metres above the level of the enclosing crater.

From May 25 to May 27 violent explosions occurred, which were heard in all the villages on the mountain-side,

lava piled itselt up in the space between the cone and the hill formed by the lava-flow of 1895; a stream branched off, first toward Mount Somma, but afterwards in a southsouth-west direction, and a small stream more fluid than the main body ran to within a short distance of the electric railway which plies between the observatory and the lower funicular station. Near the fumarole "B" a small heap of scoriæ (a driblet-cone), about 4-5 metres in height, has sprung up; but apart from the explosions attendant on its formation, and which only lasted a few days, there has been no disturbance in the regular flow of the great streams.

The line of white steam seen in Fig. 2 shows the position of the outlets and the course of the lava streams as seen from the observatory ridge; the black smoke issuing from the crater indicates the cloud of nonincandescent dust which was cast up after the partial falling in of the walls of the smaller cone on the summit.

We may perhaps attribute the frequency in these latter years of the lava streams from lateral outlets to the increased height of Vesuvius (now about 1330 metres), for the column of fluid lava, when inside the cone, is forced up to a higher level and exerts greater hydrostatic pressure on the sides of it, which are, moreover, much scamed Formerly. when the mountain was lower, as, for instance, between the years 1840 and 1850, the lava streams generally flowed from the top.

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and were accompanied by the ejection of much red-hot and liquid matter. These explosions ceased almost suddenly on the evening of May 27, and at about 6.45. a small lateral outlet, “ A," burst through the north-west flank of the great cone at a height of about 1245 metres, and at the point where a seam in the mountain-side showed where the traces of the last eruption of August 26, 1903, still lingered.

A few hours after the first, a second outlet was formed, then a third, “ B," both lower down, at an altitude of

The Millport Marine Station Since the efficiency of such an institution as a biological station is so largely dependent upon the completeness of its library, I do not think any apology nerd be offered for appealing to those readers of NATURE who are interested in marine biology for assistance in an endeavour to bring together for the use of those working at the Millport Marine Station as complete a collection as may be possible of works having any bearing on the fauna and Gora of the European seas. The station already possesses a considerable proportion of the more important monographs, as well as a number of useful pamphlets; but there are still lacking many reference works of importance, and I am sure that copies of some of these will exist among the duplicates in many a naturalist's library. I would also urge the claims of the Millport Station upon the generosity of authors for separate copies of any papers they may publish ; and in this connection it should be noted that the council of the association has recently agreed that all material intended for private research shall be supplied absolutely free of charge.

This occasion may also be utilised to point out some of the advantages which the Millport Marine Station offers to the research student. The fauna of the Clyde area is an extremely rich one, and the water in the vicinity of the station is of most remarkable purity, so that even quite delicate species can be readily kept alive in the tanks. A small steamer, the Mermaid, specially built for scientific research, is constantly at work during the summer months, and brings in daily an abundant supply of material. The tank-room, only part of which is open to the public, has recently been greatly extended, and now has facilities which are probably unsurpassed anywhere for the accommodation of invertebrates and the smaller vertebrates; the tanks are mostly of glazed fire-clay, and capitally adapted for observation and experiment. Besides a well-equipped private research room, there are seven screened compariments in the general laboratory affording ample accommodation for nine students, while a large class-room recently added has benches for forty-five students.

The station is lavishly equipped with apparatus of all kinds-for instance, the student will find here every facilir for advanced physiological work. In fine, I think it may fairly be claimed that nowhere in the British Isles will the student find facilities for research on marine biologs such as exist at Millport; and, indeed, I know of no marine station elsewhere which can, all things considered, offer greater advantages to the biologist. Lastly, it may be mentioned that although the fees are very low, there is never any difficulty in arranging for a free table.

S. PACE (Director). Millport Marine Station, N.B.

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about 1180 metres, and both westward of the first, and nearer the station of the funicular railway.

For some weeks lava issued from these outlets and flowed down the mountain-side in two parallel streams, which from Naples had the appearance of two lines of fire running down the slope of the great cone; towards June 25 the current from “A” ceased, but the stream from "B" continued, and flows more actively than before. On reaching the base of the great cone (800 metres), the

THE TOTAL SOLAR ECLIPSE, AUGUST 30. have been previously calculated, give us 16 seconds

and 5 seconds respectively before the commencement (1) The Solar Physics OBSERVATORY EXPEDITION.

of totality. The object of employing these times is

Palma, August 26. not so much to assist the observers in the camp IN another four days the eclipse will be an event generally, as to warn the workers with the prismatic

of the past, and we shall be packing up the cameras, who begin making their exposures three great amount of material which we have been setting seconds before the commencement of totality. Both

Mr. Butler and myself utilise these two signals to begin our series of snap-shots for photographing the lower chromosphere.

Undoubtedly the three minutes three seconds, the length of totality at this station, is a long time, and when the strong voices of the timekeepers are heard shouting out “ 163 seconds," " 153 seconds more,"

&c., one somehow feels that one FIG. 1,-Our camping ground as seen from the south-east end. n the long tent on the left is the

is not utilising to the fullest 76 st. prismatic reflector, and all the other instruments are beyond it. Notice the poles for the extent the time available. discs in the right-hand corner.

With the prismatic camera,

of which I am in charge, up with so much care since August 11. The greatest it is hoped to secure fourteen photographs. The three keenness has been displayed in every party told off large 6-inch prisms of 60°, and the object-glass of for its particular duty, and I think that everyone will the same diameter, form together a powerful weapon be glad when the eventful day arrives.

of research. The programme of work is to make We have settled down to routine work every day. Those in charge of instruments go to the camp at about 6.15, and work at the adjustments and small items so necessary for successful photographs. At nine o'clock the whole band of volunteers, now about 150 in number, arrives at the camp, and three drills are then gone through in fairly quick succession. The organisation of the division of labour at each instrument is now Fig. 2.-The camp as seen from the south-west end of tbe ground. The 3-inch McClean equatorial very satisfactory, and the various

in the foreground, 16 ft. coronagraph under tent on left, 76 ft. prismatic reflector under canvas on

the right. All these instruments are housed with sails and spars from H.M.S. l'enus. movements that have to be performed at stated times occur in clockwork | four snap-shots at about the commencement of totality fashion.

and five about the end. The remaining five plates As I have mentioned before, the whole work of the will be exposed for intervals varying from 5 to 90 camp is organised according to signals given by the seconds, and it is hoped that the two long exposures

on each side of mid-totality will add to our knowledge of the wave-lengths of the coronal rings. This prismatic camera is designed to give results suitable for determining accurate wave-length of the chromospheric and corona arcs; the image of the sun is therefore small, and the dispersion large.

The prismatic reflector of 76 feet focal length, in charge of Mr. Butler, provides a solar image of about 8 inches diameter, and, since the light is made to pass through one prism twice, the dispersion is not excessive. The large chromospheric arcs should, however, provide us with much matter for thought.

This latter instrument is practically ready for the eclipse, and a few words may here be said as regards the erection of it. The camera end itself forms part of the dark room of the camp, and is to the south of it. Just outside, but a little to the west of the north and south line, is the siderostat, which

athrow's the solar rays on to the long-focus mirror FIG. 3.-The north end of the 76 st. prismatic reflector, showing the dark

situated to the south about 70 feet. This concave room with the wine-tub for water, the two handcarts lcaned us, and on the right, under the small awning, the 3-prism 6-inch prismatic reflector throw's the image towards the north, into camera.

the portion of the dark room in which is fitted a

screen. An arrangement is adopted for inserting, eclipse clock. There are, however, two further during some periods of totality, a prism in front of signals given from the angles subtended by the cusp the mirror. The light from the siderostat has thus at the centre of the dark room. These angles, which to pass twice through the prism, giving a very useful spectrum. The large size of the image involves the most heartily both Staff-Surgeon Clift and Surgeon use of very great photographic plates, and in this Jones, of H.M.S. Venus, for their very kind and case plates 2 feet square and 2 feet by i foot will be efficient assistance on that occasion. used.

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The camp at the present time practically fills the In order to keep out the light from the cloth tube whole of the enclosed ground placed very generously connecting the mirror with the camera, sails have at our service. Through the kindness of the local been erected on large spars, making the whole tube authorities, extra tents have been provided, and much a very imposing structure.

material loaned in the way of wood for the shadowTwo new additions to eclipse drill have been intro- band party, handcarts for the use of the men bringduced to render the organisation more perfect and ing water and provisions from the ship, &c. flexible in exceptional circumstances, and both of To avoid the inconvenience of any dust arising these have been proved to be necessary. During one from the road to the north of the camp, the same

authorities will keep this well watered on the day of the eclipse, and for some days previous to it, and they have also arranged that the manufacturers' chimneys, which are very numerous here, shall not smoke during the time of the eclipse.

WILLIAM J. S. LOCKYER.

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(2) REPORTS OF OBSERVATIONS. Up to the time of writing very few details as to the actual scientific results obtained during the total eclipse of the sun on August 30 have arrived in this country; but it is very clear that the hopes expressed in these pages on August 24 have not been completely realised on account of the prevalence of cloud during totality at several stations.

Telegraphing from Castellon, Prof. Callendar states that, although the first and last contacts were observed in a clear sky, totality was entirely obscured

by clouds. Good records of radiation and temperaFig. 4.— The timekeepers at work with the eclipse clock, and their audience.

ture were, however, secured. Similarly, Mr. Ever

shed, who had set up a very fine prismatic camera of the rehearsals the other day

day the eclipse clock | near to Burgos, says in a telegram
the eclipse clock

to the Royal stopped owing to the hand coming in contact with Society, “ Thick clouds; no results." This forms the dial over which it moves. Such an occurrence

a striking contrast to the reports of the Press correhas never been known in our eclipse history before,

spondents, which state that all the observations at and the timekeepers remained dumb after counting Burgos itself were successfully carried out during a " 163 seconds more.” In future, a man with a stop- temporary break in the clouds. A reproduction of a watch will stand with the timekeepers and keep a photograph of the corona, taken with a camera of tally of the 10 seconds as they pass.

48 inches focal length by Mr. J. T. Pigg at Burgos, The second innovation was prompted by the possible appeared in the Daily News for September 2. absence on the day of the eclipse of any one member

At Palma, Majorca, the expedition from the Solar of a group working an instrument. Unfortunately, I Physics Observatory, South Kensington, under the

direction of Sir Norman Lockyer, and assisted by the officers and crew of H.M.S. Venus, were apparently only a little more successful, for as the crucial moment of totality arrived dense clouds came up and obliterated the sun. At about mid-totality, however, a break in the clouds occurred, and some photographs were secured which, it is hoped, may at least show the form and extent of the corona. Several good drawings of this feature, which was of the "maximum" type seen in 1871 and 1882, were made by the “ disc " sketching parties.

At Saragossa, cirrus clouds prevented observations being made.

Encouraging but brief reports have been received from the observers at the North African stations.

Mr. Newall, at Guelma, appears to have been singularly fortunate, for he reports “superb weather conditions, observations successfully made," and

states that he observed a brilliant corona of the Fig. 5.-The cælostat end of the 16 ft. coronagraph, which is under the “ maximum ” type having remarkably long streamers tent on the right.

—one of which extended towards Mercury for more

than three degrees—and unusually dark rays. had to spend the whole of Saturday, August 26, in . Splendid prominences were also observed by him. bed by the doctor's orders; but my instrument was Sir William Christie's report from Sfax is not very efficiently worked by the navigating officer, | quite so sanguine, for he states that the sky was Lieut. Horne, who will make the cusp observations partially cloudy; nevertheless, photographs were from my siderostat during the eclipse. In each party, secured with all instruments, and the eclipse was then, the work of each member was changed, and satisfactorily observed. A Reuter telegram from this drills were carried out under this scheme with success. station says that during the period of totality no I should like to take this opportunity of thanking clouds interfered with the observations.

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At Assuan, where Prof. Turner set up his corona contour of the moon projected on the corona immedigraph and polariscopic apparatus, the atmospheric ately after the first contact. . Thermometric observconditions were perfect, except for a slight haze, and ations showed a fall from 90° to 72°.6 in the sun, the Times correspondent reports that eight photo and from 820.4 to 72°.5 in the shade, temperature. graphs in polarised light were obtained and successful Mr. Bacon, first officer of the Arcadia, made corona pictures were taken. Mr. Reynolds with his successful observations of the approach and of the 120-feet reflector evidently experienced the great recession of the moon's shadow from a point of drawback common to all users of long-focus cameras, vantage at the mast-head. viz. bad atmospheric tremors, for the local fire brigade As regards the observations made by foreign astrohad to be requisitioned to flood the site in order to nomers, those located at Castellon, Burgos, Guelma, check the radiation from the heated ground.

Sfax, and Assuan shared, of course, in the conditions. Dr. J. Larmor sends us the following observ- enumerated above. M. Trépied, of the Algiers ations made by Mr. S. L. Walkden on the Orient Observatory, was apparently very successful at steamer Ortona, situated on the central line of the Guelma, and obtained numerous photographs of the eclipse in the Mediterranean near the Spanish coast. chromospheric spectrum and the corona. A fall of The observations contain a good naked-eye record of the temperature of 5° C. (from 33° to 28°) was recorded, eclipse, and agree with Dr. Larmor's impressions : and Mercury, Venus, and Regulus were observed. "Rainbow colours . visible on small cloud about 50 At Tripoli, Prof. Todd, of Amherst College Observfrom sun about minute to i minute before totality. atory, M. Liberd, of Paris, and Prof. Millosevich, of Pulsation of light from strip of sun was observed by Rome, were favoured with a clear sky. Prof. Todd Mr. Campbell and myself as if the moon advanced secured some 250 photographs of the corona with his by stages. (Probably another aspect of shadow-bands automatic coronagraph. Very good observations of phenomenon.) No approach of shadow observed by the shadow-bands are said to have been made at this myself, though keenly looked for; but found no one station. else who observed it except Mr. Campbell, who caught A disappointing feature of the eclipse was the it in the sky not far from sun's limb at time of failure to secure observations at both ends of the approach of totality. Totality.- Venus first noticed shadow's path. As mentioned before in these about one minute before totality, and Regulus as soon columns, arrangements had been made by the Lick as totality complete. Mercury searched for with Zeiss Observatory to photograph the corona in Labrador field-glass and naked eye, but not caught after about and in Egypt with exactly similar coronagraphs. 10 to 15 seconds' search. Corona.-Very fine and very | Mrs. Maunder, accompanying the Canadian party at detailed, so that general description difficult. General | Hamilton Inlet (Labrador), was also to use a coronaimpressions.-(1) Some streamers seemed to cross, and graph identical in scale with that used by Prof. were certainly not all radial. (2) Obvious extension Turner at Assuan. A Reuter telegram from St. seemed about two sun diameters. (3) Streamers dis- | John's, Newfoundland, announces, however, that the tributed all round sun, but chiefly at left-top (45° | Lick observers experienced a total failure owing to from top) limb. Long thin streamer at left-left clouds; a second message from a telegraph station bottom limb (671° to left of bottom). Prominences. on Hamilton Inlet stated that fine weather prevailed Distributed more or less all round, but chief one from 7 a.m. to 6 p.m. on the day of the eclipse, and observed at left-top corner. Height about of that the phenomena were perfectly visible, and it was sun's radius; but this should be corrected for irradi hoped that the Canadian party had been successful in ation, which made the prominence appear to trespass making good observations. A later telegram, dated into the moon's surface, exaggerating its size and September 3, states, however, that the expedition was producing general local glare. Colour of prominence entirely unsuccessful, owing to the cloudy weather, was much less marked than expected, being merely and no photographs were secured. of a violet or faintly rosy-pink hue. Shadow bands A communication from Mr. J. Y. Buchanan, observed on deck at end of totality (looking down F.R.S., to the Times of September 5, contains some from boat deck). They'rippled' along a little | interesting notes of visual observations made during faster than could be easily followed by eye. They the period of totality at Torreblanca, a small village were parallel to the strip of the sun after totality, and on the east coast of Spain. Having been present at travelled in direction of shadow. Dark strips about the 1882 eclipse, when he assisted Sir Norman 6 to 8 inches wide, distance apart about 18 inches. Lockyer at Sohag, on the Nile, and not having seen During totality depth of darkness seemed practically the whole of the phenomena, Mr. Buchanan only independent of depth of our immersion in shadow. took with him an ordinary camera and a field-glass, Clouds formed a good deal after of sun's diameter so that he might devote all his attention to visual had gone. Lightness of eclipse very marked, and in observations. His choice of Torreblanca, where, with itself disappointing. Time by watch always plainly the exception of the local railway employees, he seems visible. Sky illumination greatest round horizon, to have been the sole observer, was justified, inasmuch and a vellow glow (like sunset) in points opposite to | as the eclipse took place in a blue sky. As the last sun (about N. point). Coast lights were visible a vestige of sun disappeared behind the eastern limb few miles away, and one hill to N. appeared as if of the moon a magnificent bunch of prominences, of perforated with the sky showing through. This a light violet hue, appeared at the same part of the was observed by one other passenger. Venus still limb; but these subsequently disappeared, and a visible nearly 5 minutes after end of totality. Whole / careful search at mid-totality failed to reveal any black disc of moon was visible shortly before totality, prominences at all. I similar group, however, burst say 5 to 10 seconds before."

into view on the opposite limb just before the end of According to a correspondent writing to the Times, totality, thus indicating that the apparent diameter some interesting observations of a simple character of the moon was sufficient to cover the whole of the were made by the amateur astronomers on board the prominence layer of the sun's limb at mid-totality. P. and 0. mail steamer Arcadia, which for the time. The corona was clearly visible near to the western of the eclipse waited off the coast of Spain not far part of the moon's limb eight seconds before the from Castellon. Members of the British Astronomical advent of totality, and throughout totality it was Association were on board, and organised themselves very clearly defined. On an average it extended to to watch various features of the phenomena. Mr. rather more than one lunar diameter from the limh, and Mrs. Johnson report that they saw the whole' but a streamer on the lower western limb was judged

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