rest during a period of fifteen minutes, the time required for elevating the hammers H and H'. As soon as this is accomplished, the lever begins to rise slowly by means of the double snail on the hour shaft, the time required for traversing the drum being about fifteen minutes. When the position of the lever is such that the carriage in the rear of the clock touches the float in the shorter leg of the siphon, an electric current is established through the magnet, F, which unlocks the hammer H, causing the pen G to make a record on the drum sheet. After the lever has reached the top of the drum, it remains at rest fifteen minutes while the hammers are being raised, when it is gradually depressed. So soon as the platinum wires attached to the carriage over the thermometers-touch the

surface of the mercury in the thermometer tubes, electric currents are established through the magnets F and J, simultaneously or successively unlocking the hammers, and, as the case may be, making records as before. A complete double motion of the lever requires one hour. During this time the barometer and wet and dry bulb thermometers have each been recorded once. The records of the barometer and thermometers differ in time about half an hour. The wet and dry bulb thermometers are recorded within about one minute of each other, depending on the difference between them.

One of the most marked and wonderful features of the invention of Prof. Hough is that it prints its own records. And this is done by a single screw, which rises or falls

with the mercury in the barometer. This screw carries a pencil, which traces upon a revolving cylinder or roll of paper a line showing the minutest movements of the column of mercury for every minute in twenty-four hours. This same screw also gives motion to a series of wheels which carry types, by which, at the end of every hour, the height of the column of mercury is printed on a slip of paper to the accuracy of the thousandth part of an inch!

One of the most beautiful and simple contrivances used is a Wild's Self-registering Barometer, of which we give a cut one quarter the actual size. It scarcely needs explanation, except to say that the tube A is suspended in a

cistern of mercury, represented on the left of Fig. 9. As the atmospheric pressure changes, the level of the mercury changes in the cistern, and the tube A rises or falls as the atmospheric pressure increases or diminishes. The weight of this tube as it floats in the mercury, and also that of the arm I, which supports it at G, is exactly balanced by the arm II, to which is attached a sliding weight, III, adjustable by a small thumb-screw. K is a steel crayonholder fixed to the balance III, and to which is fixed a crayon, c, whose point in seen in B to impinge upon a sheet of paper, 77. This sheet s moved by clock-work. When the atmospheric pressure is increased, the tube A is forced to rise a little out of the mercury in which it

B

floats, and as it rises at G, the arm / is elevated. The crayon holder, being fixed on the balance at the fulcrum, f, by two little screws, swings a little to the left, and the crayon which it carries with it makes a mark on the paper beneath it, which mark indicates the rise of the barometer, or the increase of atmospheric pressure. If the pressure decreases, the pencil, of course, moves in the opposite direction, and shows the barometric fall. The roll of paper on which the record is made by this automatic instrument is divided into rectangular parts, each one of which exhibits the atmospheric variations for twenty-four hours. At the end of every day this part of the roll is detached and put by to be bound up in book form in the records of the office in which the instrument is kept.

nothing is wanting to give reliability to the published results and the "probabilities" issued from his officers. A self-registering barometer, as well as other instruments

THERMOMETERS.

FIG. 10.-DRAPER'S PHOTOGRAPHIC REGISTER OF BAROMETER AND THERMOMETER AT NEW YORK, APRIL 28, 1871 The upper line of the Thermometer is the Dry Bulb, the lower line is the Wet Bulb

FIG. 11.-PHOTOGRAPH OF A STORM.-(Print from Photographic Register from Noon, December 11, 1870, half-inch per hour.) Two Thermometer and One Barometric Curve

The roll of paper is on a reel,, passing between two rollers, g and k, as seen in B (Fig. 9).

By these perfectly simple devices, instead of obtaining only three daily recorded observations, the observer at every station gets a continuous and perpetual record for every second in the day. That is to say, instead of getting, as by the common barometer (observed three times a day), observations for three seconds in twenty-four hours, he gets them for as many seconds as there are in twenty-four hours, or 86,400. Thus it follows that the value of the self-registering barometer, as compared with the ordinary one, is as 86,400 to 3!

The marvellous accuracy and exquisite nicety with which all the observations forwarded to General Myer by the observers are marked ought to assure the public that

of equal sensitiveness, will be used by all the observersergeants. It is scarcely possible for this invaluable instrument to suffer derangement or to get out of order. A third most beautiful and sensitive self-registering

instrument is that of Mr. Peelor, of Johnstown, Pennsylvania, used with great success and satisfaction by the Signal Service. This needs no battery, no electricity, to work it. A simple clock-work is all that is required, and its operations are as exquisitely accurate and trustworthy as the best navy chronometer.

A barograph and thermograph made by Mr. Beck, of London, similar to those used in the Kew Observatory, are on trial in the Signal Office, and good results are hoped from them. Their beautiful machinery might also be mentioned and described, but our space fails. Indeed, our limits have allowed mention to be made only of the most novel instruments employed by the signal offices. A specimen record of one of these is presented in Fig. 10, showing the synchronous readings, on a given day and at a given place, of the thermometers (wet and dry bulb), the hygrometer, and the barometer, all upon one sheet of

paper.

We have already spoken of the beautiful adaptation of Prof. Hough's Meteorograph to the work of printing its own registrations. The mechanics of meteorology have been advanced one step higher than this, and the registrations of the automaton are instantly and perfectly photographed. The sheet of paper, suitably prepared for photographic impressions, is made to slide, by means of clock-work, before a gas flame. The mercury in the tubes protects a portion of the paper from the action of the light of the lamp, while above the mercury the rays of the lamp fall unobstructed upon the paper, and, making their impression, reveal the exact height of the mercury in the tubes.

The "photograph of a storm," Fig. 11, shows the movements of the mercury in the two thermometers and barometer for twelve hours.

This process, by which the weather is photographed, is employed by General Myer, and these necessarily exact records will prove most attractive pictorial representations of the great storms in the atmospheric ocean for the study of meteorologists all over the world.

of the Archduke Rainer.

The Exhibition is intended to be opened on the 1st of May, 1873, under the especial patronage of the_Emperor and his brother, the Archduke Charles Louis. The Commission, which is composed after the models of the English and French Commissions, consists of the Archduke Rainer, president; the Lord Steward of the Imperial Household, Prince zu Hohenlohe-Schillingsfürst; the Imperial Chancellor, Minister of the Imperial House and for Foreign Affairs, Count von Beust; Prince zu Liechtenstein. Prince Schwarzenberg, Count Festetitz, and Count Potocki, vicepresidents; and the Lord High Chamberlain, Count Folliot de Crenneville, and other high courtiers, the Ministers and heads of departments, the Presidents of both Houses of the Reichsrath, the presidents of the chief artistic, commercial, and scientific societies, and a number of gentlemen who have distinguished themselves in the various branches of science, art, and industry.

The entire arrangements have been entrusted to the Austrian Consul-General at Paris, Privy Councillor Baron de Schwarz-Senborn, who has been nominated DirectorGeneral of the Exhibition. Local committees are about to be formed in the various provinces of Austria and Hungary, and a special Royal Commission is to be appointed at Pesth. The objects to be exhibited will be

classified into 26 different groups, as detailed in the suboined programme.

One great feature of the Exhibition will be an arrangement for the classification of the productions of all countries in groups corresponding with their geographical position, and great pains will be taken to render the Oriental department in every way worthy of the almost inexhaustible resources of the Indian Empire. The position of Vienna is admirably adapted for this, having, besides the waters of the Danube, a direct communication with all the important harbours of the Levant via Trieste. The arrangement of the Eastern department will be confided to the Austrian Consul at Constantinople, Dr. de Schwegel, who has already acquired a great reputation for his knowledge of Oriental habits and productions.

A new feature of the Exhibition will be an arrangement by which the treasured collections of the various museums of London, Paris, Berlin, Moscow, Lyons, Munich, Stuttgard, &c., will appear in simultaneous position, and it is further intended to represent a history of inventions, a history of prices, a history of industry, and a history of natural productions, so that the world's progress in arts, science, industry, and natural products, will thus be brought into contrast. The Emperor of Austria has granted the use of the "Prater" for the site of the exhibition, and Mr. Scott Russell is at present in Vienna consulting with Baron von Schwarz as to the design for the building. Chevalier de Schaeffer, Director of the Austrian Consulate General in London, who gained great experience at the London and Paris Exhibitions, has been entrusted with the preliminary arrangements respecting the contributions to be sent to the Exhibition from Great Britain.

The objects to be exhibited will be classified in the following twenty-six groups :-1, Mining and Metallurgy; 2, Agriculture and Forestry; 3, Chemical findustry; 4, Articles of food as industrial products; 5, Textile industry and clothing; 6, Leather and india-rubber industry; 7, Metal industry; 8, Wood industry; 9, Stone, Earthenware, and Glass industry; 10, Hardware industry; ¡I, Paper industry; 12, Graphical Arts and Industrial Drawing; 13, Machinery and means of transport; 14, Scientific instruments; 15, Nautical instruments; 16, Military accoutrements; 17, Maritime objects; 18, Architectural and Engineering objects; 19, Cottage houses, their interior arrangements and decorations; 20, Peasant houses, with their implements and arrangements; 21, National domestic industry; 22, Representation of the operation of Museums of Art and Industry; 23, Ecclesiastical Art; 24, Objects of Art and Industry of former times, exhibited by amateurs and collectors; 25, Plastic Art of the present time; 26, Objects of Education, Training, and Mental Cultivation.

Arrangements will be made for temporary exhibitions of such articles which by their nature do not admit of an exposition of long duration.

During the time the Exhibition is held, International Congresses are contemplated for the discussion of important questions to which either the Exhibition itself may give rise, or which may be specially suggested as themes suitable for international consideration.

The arrangement of the Exhibition will be geographical, that is to say, according to countries, but in such a manner that the different territories of production shall appear as nearly as possible in the same order as they are situated naturally in the direction from the west to the east.

SCIENTIFIC USE OF THE MONT CENIS TUNNEL

AT T the sitting of the French Academy of Sciences on the 18th inst., M. Elie de Beaumont read an elaborate paper on the scientific instruction which may be derived from a close examination of the collection which is to

be exhibited in the School of Mines in Paris of specimens of the strata obtained from the Mont Cenis Tunnel. This collection, which consisted originally of only 127 specimens, has received 69 new specimens, which brings the total number to 196 altogether.

The total vertical thickness of the strata explored was more than 7,000 metres. The general colour is grey, or, rather, black, and the colouring matter is mostly carbon. Very few fossils were met with, having been destroyed by the subsequent crystallisation.

The disturbances which have created Mont Cenis and made it emerge from the bottom of the sea have produced many cracks and faults. But all these faults have been filled up with quartz in a perfect manner in relatively modern times. The infiltration amounts practically to nothing. The only spring which was discovered is situated near Modane, and gives only seven gallons per minute. The water is cold. The contractors were obliged to send to Modane and Bardonnèche for the water required for drinking, and for grinding the stone.

Mont Blanc, although 4,800 metres above the level of the sea, is only 3,500 above its own base. The vertical section of the perforated strata is thus equal to two Mont Blancs; and it is something like one whole Himalaya. M. Sismonda, Professor of Geology at Turin, presented to the Royal Academy of Sciences, Turin, in the sitting of the 5th of December, 1866, a paper entitled Nuove osservazioni geologiche sulle rocce anthracitifere delle Alpi, at the end of which was printed a map drawn by M. Sismonda twenty-five years ago, and exhibiting the theoretical succession of strata. Everything was found in the place where it was supposed to be by M. Sismonda.

No artesian well has ever given an opportunity of comparison with the perforation of Mont Cenis, as the deepest bored by European engineers is only 1,000 metres, and by the Chinese only 3,000 metres.

The Academy listened during more than an hour to the lecturer. M. Faye presented to the learned Perpetual Secretary the hearty thanks of the Academy, and expressed a wish that a series of pendulum experiments should be conducted on the top of Mont Cenis as well as in the central part of the tunnel, to test the effect of the mass of the mountain on the time of the oscillations.

NOTES

We believe that the stations to be occupied by the Eclipse Expedition are Baikul, Gunote, and Manantoddy, near the Malabar coast; Poodoocottah, near Trichinopoly; and Jaffa, in Ceylon. These arrangements are necessitated by the information received as to the weather chances from the Viceroy of India and the Governor of Ceylon, who are taking the warmest interest in the intended operations. It is hoped that Prof. Stokes will take charge of the Expedition, and in this hope we venture to join very warmly. As our leading physicist, as Secretary of the Royal Society and potential President, as one who has so closely studied solar physics and the methods of attack contemplated-on each and all of these accounts it is obviously for the advantage of science that the Expedition should be under his command. The Committee has communicated by telegram with Prof. Peirce, expressing a hope that the Expedition may be strengthened by the addition of some American observers who are all veterans in eclipse matters. Prof. Respighi has also been invited to accompany the party. We must not omit to add that Lord Lindsay has supplied the Committee with many valuable instruments, and is aiding in other ways.

DR. CARPENTER arrived at Malta in the Shearwater last week, and has been engaged in conjunction with Captain Nares, commanding that vessel, in a series of researches on the Gibraltar current, intended to complete the inquiries made last year in the Porcupine. The existence of the outward undercurrent, which was indicated by the experiments of last autumn, has now been

This position depends on comparison with one of Bessel's stars extending over more than an hour, during which motion in the right direction for Encke was apparent. Though very faint, it is hardly more so than Mr. Hind expected to find it from previous experience. We may look for a fine telescopic object in November, and one just visible to the naked eye after the middle of the month and in the first days of December, before it gets too near the sun's place to be observable.

THE College of Physical Science at Newcastle-on-Tyne has issued the prospectus of its first session, to open October 7. The following is the programme of studies:-Prof. Aldis will conduct three classes in Mathematics; two for junior students, and one for any who may enter with sufficient knowledge to enable them at once to take up subjects which will in future be ordinarily read by students in their second year. There will also be an Exercise class for all the students. In Experimental Physics, Prof. Herschel will have two classes; the advanced class will contain experimental illustrations of Practical Mechanics, and of Heat considered especially with reference to its application in mining, manufactures, and to the steam-engine; but there appears to be no provision for practical laboratory work. In Chemistry, Prof. Freire-Marreco will conduct both the course of lectures and the practical course in the laboratory. Prof. Page will deliver a course of lectures on Geology, and will accompany the students in field excursions or visits to museums. As yet there is no immediate prospect of a chair of Biology, though we understand its creation is a settled thing as soon as funds allow. The medical degrees at Durham University can now be taken without residence, but an additional year must in that case be made at Newcastle. The College has taken off the hands of the College of Medicine the new lecture room, built expressly for Chemistry and Physics, and the laboratories.

THE Chargé d'Affaires of the Japanese Government in this country, who has looked with longing eyes on Messrs. Cooke's great equatorial, the gem of the present International Exhibition, should also inspect some meteorological instruments for transmission to Japan. The following extract from a little illustrated news-sheet now being hawked about Yedo, giving an account of the late typhoon in the inland sea, and a picture of the appearance of Kobe Bay after it, will show that the Japanese have as yet quite elementary notions in meteorological science :-"The Great Storm-Wave in Kishiu, Idzumi and Setsu.-The sudden changes and movements of heaven and earth are caused by the commingling of the female and male elements, and the conten

tion of wind and rain. Alas! not even can the influence of the

gods of Buddah prevail to govern them. It was on the night of the 18th day of the fifth month of the fourth (goat) year of Meiji, and about ten o'clock, that the wind and rain became exceedingly violent, and a great storm-wave arising, not only the steamers, but also about 700,000 large and small boats were thrown ashore at Kinohana and Kumanoura in Kishiu, at Sakai, and at Tempozan off Osaka. At the frightful destruction, old and young, males and females, wept and howled; and the sound thereof was most pitiable. The number of the dead was in proportion to the size of the places (visited by the storm). It was