FIG. 4-Law of the attraction and repulsion of a current by a current. withdrawn from the coil; and Wheatstone, who in 1843 proposed to register observations of astronomical instru

were not

ments with a view to determine longitude, and who shortly afterwards published, in the Philosophical Transactions, his investigations into the laws that regulate the transmission of electric currents through metallic conductors then developed into any practical form; it was only about that time that public attention became directed to the probable future of the electric telegraph. The exhibition instruments open to the public at one shilling each, between Paddington and Slough, were the means of bringing to justice the perpetrator of a foul crime. These early double-needle instruments, long since obsolete

FIG. 5.-Induction by a magnet.

In those days electrical knowledge was in its infancy : the very wire between Paddington and Slough was insulated partly by silk and suspended through goose-quills attached to the posts along the Great Western Railway. In those days of electrical innocence the practical value of the return-circuit by means of the earth was undeveloped. As early as 1840 Wheatstone first conceived the idea and published his plans for transmitting messages under the sea by means of a submarine cable. That scientific men at that time considered that such a discovery would lead to most important results is testified to by the Abbé Moigno, who writes that it was announced by Wheatstone in 1840 that he had found the means of transmitting signals between England and France, notwithstanding the obstacles of the sea; and he emphatically adds: "I have touched with my hands the conducting wire which, buried in the depths of the ocean, will unite instantaneously the shores of England with the shores of France." In 1844, at Swansea Bay, off the Mumbles Lighthouse, the first practical experiment took place, and signals were transmitted from an open boat to the shore from a considerable distance. In the boat sat the inventor, Wheatstone, his eyes eagerly watching his galvanometer for the coveted signals signals that would tell him his hopes were realised, and

FIG. 7.-System of two magnetic

needles, with their poles reversed, forming an astatic combination, neutralising the effects of terrestrial magnetism.

CLAPLANT

FIG. 6-The Cook and Wheatstone double-needle Telegraph : 1845. as regards construction, have been preserved as indicating he first era in telegraphic communication.

FIG. 8.-Astatic Galvanometer.

that he had triumphed over the elements. The last twentyeight years have given birth to many wonderful and practical results. Between 1844 and 1848 railways were in their infancy; their limit of distance as compared with their present extent was very circumscribed. Equally so was electrical knowledge, as compared with the requirements of extended distance. In 1848 Holmes gave to telegraphy the practical result of his researches as regards the rapid transmission of signals over extended circuits. In those early days the five-inch astatic needles and coils of the Cook and Wheatstone system were absolutely useless for longer distances than one hundred miles, and as railways extended, so telegraphic difficulties were

found to multiply. The introduction of gutta-percha in 1850 and a more perfect knowledge in the preparation of indiarubber as insulating mediums for electrical purposes have been the means of establishing upon a commercial basis electric communication between the chief empires of the earth, have united the eastern and western hemispheres by metallic highways of thought, threading the trackless ocean with its mysterious depths. It is thus that the primitive experiment of Wheatstone in 1844 has developed into the stupendous telegraphic undertakings that encircle the globe, uniting with a common interest all nations, creeds, and languages.

The principal laws that regulate the transmission of electric currents through metallic conductors are simple, and may be briefly described with sufficient distinctness to enable the general reader to grasp the intricacy and magnitude of the science of electric transmissions.

Leaving on one side the old accepted terms of conductors and non-conductors, for the present purpose all substances in nature must be regarded as able more or less to conduct a current of electricity.

As the various substances, gums, glass, wood, earths, liquids, or metals are examined, it will be found that some afford much greater facility for the transmission of electricity than others; consequently, if they are arranged according to the resistance offered to the current, a list somewhat similar to the annexed will be presented, commencing with those of least resistance: copper, iron, plumbago, sea-water, rain-water, snow, steam, moist earth, oils, ice, phosphorus, porcelain, baked wood, dry paper, hair, silk, mica, glass, wax, sulphur, shellac, gutta-percha, india-rubber. It therefore naturally follows that where it is required to construct a system of submarine circuits for the conveyance of electric currents from one place to another, some metal, such as copper, is selected. Water being also pretty high in the scale, it is essential that to prevent leakage or loss of current in its passage through the wire, a gum such as gutta-percha or indiarubber, offering a high resistance, should be selected in which to enclose the conducting wire and give proper insulation to the circuit. It is therefore evident that the perfection or freedom from loss or leakage in an electric circuit is simply relative as regards the material employed, and insulation means the obstruction or resistance placed in the way to prevent the escape of electricity from the conducting wire. Various important phenomena come into play in connection with the passage of an electric current through an insulated circuit, which it is necessary to explain in an elementary manner. Induction, or the production of an electric current moving in an opposite direction to that of the current passing through the insulated conductor, takes place in the adjacent medium to that of the insulated wire; that is to say, supposing an insulated metallic circuit-a submarine cable-is fulfilling its duties in the tran mission of an electric current throughout the metallic conductor, the effect of that current will be to set up a second current in the water moving in an opposite direction. This opposite or induced current is well illustrated by the Leyden jar familiar to everyone. The inside metallic foil represents the copper wire, the glass separating the foils the insulation of the cable, the external metallic coating the water surrounding the cable. On electrifying the Leyden jar the internal and external metallic coats become charged with electricity in opposite states. The effect of this induced current on submarine cables is to retard or pull back the flow of the primary current, sensibly diminishing the speed of transmission as compared with that of a land line of telegraph. On a land line with a single wire the effect of induction does not take place, because the metallic conductor, generally iron, requires no insulating medium to enclose it, the air itself taking the place of the insulator; the wire requires to be insulated only

at the points of support, the tendency of these being to produce a leakage or weakening of the current from water and other substances held in suspension in the air, impairing the integrity of the contacts at the points of sus pension. Induction, however, takes place with land wires under certain conditions, namely, when two or more are suspended closely together; a current through one wire will then produce an induced current in an opposite direction in an adjacent wire. Induction increases with the extent of surfaces of the copper conductor and the insulator with which it is covered diminishing the speed of transmission.

Insulation may be obtained by a very thin covering of the insulating medium. Increase in the thickness of the material only mechanically renders the covering more secure. The effects of induction are decreased in proportion as the insulating substance is increased in thickness, the conducting wire remaining the same; with an infinite insulation like the atmosphere, induction would cease.

With insulated wires, absorption (inductive capacity) takes place. No substance in nature has yet been found that will not absorb some other element, force, or matter in a greater or less FIG. 9.—Charging the Leyden jar. degree. Heat, light and electricity, liquids, gases, and metals under varied condi tions are all alike susceptible, and will either be influenced or retain in different proportions the various elements, forces, or matters brought into juxtaposition with them. At present it is only necessary to investigate the phenomenon of electrical absorption or inductive capacity. Thus, when a current of electricity passes through an insulated metallic circuit, certain known effects take place. Resistance, which impedes the direct progress of the current; induction, or the setting up of a counter-current moving in an opposite direction, and exerting, as it were, a pulling back of the original current; absorption, or the sucking up into the substance of the insulating material of a sensible integrant of the original current. Various insulating gums, as gutta-percha and indiarubber, have different properties as regards the insulation or resistance to the lateral escape of the electric current they enclose, namely, the inductive effect in proportion to the insulation, and the absorption of the current as it flows through the conducting wire enclosed by them. Asa sponge sucks up water, so to a certain extent does the insulator of the submarine wire absorb the electric current, the result being that, instead of the current passed into the wire at one end flowing through and emptying itself out at the other end of the wire, the current will now out and leave a residue behind, an appreciable time being required for discharge to clear the line. This absorption of the current leaves the line clogged for the receipt of the next current, and greatly interferes with the rapid transmission of currents through insulated metallic circuits. It is therefore only in short cables that the transmission of the current may be considered instantaneous. In cables exceeding 150 miles in length, electric currents have a sensible duration. (To be continued.) ·

DUCED IN IRON AND STEEL BY THE ACTION OF HYDROGEN AND ACIDS

FOR

OR a long time it has been well known to wiredrawers and other manufacturers, who free the iron or steel they are engaged in working from rust by cleaning it with sulphuric acid, that after this process the metal becomes much more brittle than before. Further, if a piece of iron wire that has been cleaned in sulphuric acid be bent rapidly to and fro till it is broken, and the fracture be then moistened with the tongue, bubbles of gas arise from it, causing it to froth. If this same wire be now gently heated for a few hours, or left in a dry warm room for some days, it will be found to have regained its original toughness, and not to froth when broken and the fracture moistened.

Some experiments made by the writer on this subject during the last three years, have shown that not only sulphuric, but hydrochloric, acetic, and other acids which give off hydrogen by their action on iron, produce the same effect, making it probable that hydrogen is the cause of the change. This view is confirmed by collecting the gas given off at the surface of the iron and burning it, when the characteristic flame of hydrogen is seen.

Putting the facts together, it seems probable that a portion of the hydrogen generated by the action of the acid on the surface of the iron is occluded and subsequently given off, either rapidly, as when the iron is heated by the effort of breaking it causing the water on the surface of fracture to bubble, or, more slowly, in the cold.

Perhaps the simplest way of charging a piece of iron with hydrogen is by laying it on a sheet of zinc in a basin of dilute sulphuric acid. An electric current is here set up, and the hydrogen generated by the action of the acid on the zinc is given off at the surface of the iron. In this way two minutes or even less will often suffice to charge a piece of iron with hydrogen and alter its properties as completely as one hour's immersion in dilute acid without the zinc.

The change in the properties of iron which has occluded hydrogen is not confined to a diminution of toughness, though this may be reduced to one-fourth, but is accompanied by a remarkable decrease in tensile strain, amounting in cast steel to upwards of twenty per cent. after twelve hours' immersion in sulphuric acid. With iron wire the decrease in tensile strain was found to be less than with steel; the reduction amounted however in some cases to six per cent. Some interesting differences are noticeable in the relative effect of occluded hydrogen on mild steel and highly carbonised steel, the diminution of tensile strain after occlusion of hydrogen being greater in the

latter case than in the former.

As with the metal paladium, so with iron, the electrical resistance is increased somewhat by occlusion of hydrogen; in fact, it seems probable that every property of iron or steel undergoes a change after the occlusion of hydrogen, and the extent of this change becomes a matter of great interest to the engineer now that iron and steel are so largely used.

Cases of the deterioration in toughness of iron of excellent quality exposed to the action of gas containing acid, as in the upcast shaft of a coal-pit, have come before the writer's notice, in which the change appeared to have resulted more from hydrogen occluded by the iron than its corrosion by the acid vapours. It is also probable that rapidly rusting iron occludes hydrogen, and is thereby weakened in strength and toughness.

WILLIAM H. JOHNSON

THE SOUTHPORT AQUARIUM THE grounds of the Southport Pavilion, Winter Gardens, and Aquarium Company occupy an area of about nine acres, extending from a portion of the sea-wall and

centre of the grounds, by the chief portico on the Lord Entering the pile of buildings, which occupy about the Promenade Hall is reached, which is constructed of pitch Street side, and ascending a wide flight of steps, the pine, and is over the principal corridor of the aquarium, to which access is obtained by descending a flight of steps, or an incline, placed on either side of the staircase leading up to the hall, which, like the corridor beneath it, is 160 feet in length by 42. To the right of the hall, and separated from it by glass doors, is the Band Pavilion, which is said to be capable of holding 2,000 people; round it is a gallery used as a promenade, and in which pictures are exhibited, and beneath it is the refreshment department, which is on the basement level. Like the aquarium,* the Pavilion is oval in shape, the longest axis being 136 feet, the shortest 76. To the left of the great hall, glass doors give admittance to a glass conservatory, 174 feet in length by 74, stocked with tropical and subtropical plants and birds; beneath it are the remaining corridors of the aquarium.

The first corridor of the aquarium contains twenty-three tanks, the front of each consisting of three sheets of plate glass, as at Brighton; and the light, as there, is all transmitted either through the water in the tanks or through roof consists of double groined arches, supported on plates of opaque glass placed in the floor above. The moulded columns, made of concrete, which has been largely used in various parts of the building with good

results.

Tanks 1 to 23 contain: Sea Anemones, Nos. 7 and 23; Octopi, 11 and 21; Crabs, Spiny and Common Lobsters, 10, 16, 19, and 22; four specimens of King Crabs, 20; Conger and Common Eels; Salmon Trout; Ballan Wrasse, 6; Rough Hound and other dog-fish; Cod and Rock Cod; Grey, Streaked, and other Gurnards; Whiting, Soles, Plaice, Bret, &c.; Father Lasher (Cottus scorpeus), 4; two specimens of the Angel or Monk Fish, 15.

By the side of the tanks, plates of fishes from Yarrel's work are hung, which, not always having any connection with the living fish exhibited, rather distract attention, and would be better collected together with various stuffed fish placed at the top of the tanks, and placed in a small museum. Amongst the plates are some original coloured drawings of Mr. Jonathan Couch, of seven species of sharks, signed "J. C., 1825"; also eight drawings of flying-fish, by the same.

Corridor No. 2 has a flat ceiling supported on iron columns, is lighted by windows looking on to the garden on the Lord Street side, and contains table tanks, rectangular and octagonal, the former being filled with fresh water, the latter with salt, containing, amongst other things, several species of Serpula, Sabella, Terebella, Amphritite, Aphrodita aculeata, and other annelides; Sea Anemones of various species; Thyone papillosa, and other Holothuriada; Ascidia and other tunicated molluscs; various species of Starfish, Cidaris; Norwegian Lobsters; Blennys, fifteen and three spined Sticklebacks, and large numbers of living zoophytes. Several of these tanks, both in the beauty of their varied contents and the care with which they have been selected and arranged, afford a good example of what can be done by art to reproduce a portion of the richness of effect of the actual sea-bottom.

On the right or seaward end of this corridor there is a Seal Tank, five seals living in it and in the Seal Pond in the garden between the entrance lodges and the portico of the Promenade Hall. On the opposite end of the corri

The ground slopes from the sea towards Lord Street, so that the aquarium is underground on the seaward side. In my "Notes on the Geology of Liverpool," NATURE, vol. ii p. 390, I have described the sand dunes, &c., of this coast.

dor is a very large tank (24), containing a large number of freshwater fish given by Mr. T. R. Sachs, of the Thames Angling Preservation Society. In tank 25 are Sea Perch; and in tank 27, which occupies the entire side of corridor No. 3, being no less than 63 feet in length by 14 feet in width, with seven feet of water, are a large number of full-sized dog-fish, a perfect shoal of large cod, and a Monk Fish more than five feet in length.

The aquarium in this direction is capable of almost indefinite extension, should the present success of the Company be maintained.

The sea-water for the aquarium is obtained from the Baths Company, who draw their supply from a point in the channel near the end of the pier, which is more than 1,400 yards in length. The water is received in a large storage tank under the conservatory, from which it travels through the various tanks, returning to a lower storage reservoir, from which it can be pumped back into the upper one, not less than 150,000 gallons of water being in constant circulation. As at Berlin and Brighton, compressed air is forced into the tanks, through indiarubber pipes; and Mr. Lloyd's plan of putting oysters into the tanks, introduced at Brighton, is adopted. The tanks, as well as the rest of the building, including the conservatory, are lighted at night by gas.

In the existence of large aquariums at Southport and Brighton, the ideas so long advocated by Messrs. Carl Vogt, Milne-Edwards, and Dr. Anton Dohrn, for the establishment of zoological stations, have to a certain extent been realised in England; but before they can be made available for original observation and research, laboratories must be built, and depot stations established at a few points on the coasts of Ireland and Scotland. Moreover, other large expenditures of an eminently uncommercial character must be incurred, which will never be entertained by commercial companies; but these, on the other hand, would probably not object to afford facilities for study if the necessary funds were found by those colleges, universities, and learned societies that prosecute the study of biological science. CHARLES E. DE RANCE

NOTES

THE Eclipse Expedition arrived safely at Point de Galle on March 15. The Indian observing party proceeds to Nicobar Island by the Enterprise, which left Calcutta on the 11th inst.

As we have already intimated, the Faraday Lecture of the Chemical Society will be given to-night in the Theatre of the Royal Institution by Dr. Hofmann, of Berlin, on "Liebig's Contributions to Experimental Chemistry."

THE service of meteorological telegrams to the ports of France was resumed on the 1st inst. The arrangements now in operation are as follows:-A large placard is sent down to be posted up in some public place, containing two specimen daily charts of the weather, and some simple rules for interpreting them. There are three blank spaces at the foot of the placard, which are intended for the chart of the preceding day from the Bulletin International, which arrives by post, and for two forecasts, morning and evening, which are to be transmitted by telegraph daily. It does not appear that there is to be any provision for exhibiting signals for the purpose of giving warning of storms. At present the only such signals which are apparently in use on the French coasts are those hoisted by the authorities of the Marine Ministry, from Dunkirk to Nantes, on the receipt of warning telegrams from London, and those hoisted south of Nantes, on the coast of the Bay of Biscay, on the receipt of orders from the Préfet Maritime of Rochefort.

THE French Telegraphic Administration has appointed two delegates to examine, in common with the Board of the Observatory, what steps should be taken to collect by wire meteor

ological information, in order to send warnings to agricultural districts. The organisation of agricultural warnings will be one of the principal subjects of discussion at the forthcoming Paris Meteorological Congress.

M. MOUCHEZ, the chief of the St. Paul French Transit party, gave before the Academy of Sciences of Paris, at its sitting of the 15th inst., the first part of his report. M. Velin, the naturalist of the expedition, brought with him to Paris three living and a number of preserved specimens of all the species of the existing fauna, which is almost entirely marine. No landing could be effected on Amsterdam Island. Saint Paul and Amsterdam cannot be regarded as the remains of a shattered

continent, but from their appearance and geological connection must have been elevated from the bottom of the ocean by individual volcanic eruptions.

WE learn from the Saar und Mosel Zeitung that we are liable to the importation not only of potato-beetles and Phylloxera, bat even shells. About fifteen years ago some small shells were discovered in the Moselle near Treves, which were very different in form from the other native species. A few weeks back the discovery was made that the same locality now abounds in this new animal, as large numbers were found in a perfectly developed state. This seems to prove that the little ones, that were doubtless imported by some raft, have grown and propagated. It is stated that the real home of this species is the Sea of Azoff and the Black Sea, and it is remarkable that they inhabit both salt and fresh water.

THE Kölnische Zeitung reports that besides Phylloxera and the Colorado Beetle a third noxious insect has come over to Europe from America; it is the so-called Blood Louse, which causes much damage to apple-trees. As a practical remedy against this unwelcome guest, it is recommended to paint the young trees with naphtha and lime-water. With arger trees of course this is impossible; but it is said that if during winter a thin lime paste is placed in a circle round the tree where it comes out of the ground, the ova of the Blood Louse are then completely destroyed.

THE discovery is announced at the Pola Marine Observatory of Planet 143, by Director J. Palisa, with a telescope of 73 ft. focal length. It appeared of the 12th magnitude, and the ephemerides given are: 1875, Feb. 23, 8h. 42m. 12s. Pola mean time; R.A., 9h. 57m. 57s. (daily motion - 60s.); and Decl + 13° 46′ (daily motion + 1'). Of the 143 asteroids, 97 have been discovered in Europe, 41 in America, and 5 in Asia.

THE celebrated physicist Amberg lately delivered three leetures at the "Volksbildungsverein" at Cologne, principally on the phenomena of Electricity, Optics, and Acoustics.

THERE will be an election at Magdalen College, Oxford, in June next, to at least one Demyship and to one Exhibition in Natural Science. The stipend of the Demyship is 95% per annua and of the Exhibition 75., inclusive of all allowances, and they are tenable for five years. Particulars may be obtained by applying to the senior tutor.

THE Council of the Senate of Cambridge University prope to offer a grace early next term for the appointment of a syndcate to consider the propriety of establishing a professorship of Mechanism and Engineering.

AMONG the papers appointed by the Council of the Ins tution of Naval Architects to be read at the meetings on the 18th, 19th, and 20th inst., are the following:-On the Talkgraph ship Faraday, by W. C. Merrifield, F.R.S.; On a mode of obtaining the outlines of sea-waves in deep water, by W. W Rundell; On the graphic integration of the equation of a ship's rolling, including the effect of resistance, by W. Froade, F.R.S., vice-president; On a method of obtaining ve

power from wave motion, by B. Tower; Notes on polar diagrams of stability, &c., by John McFarlane Gray; On compound engines, by R. Sennett; On the Bessemer steamship, by E. J. Reed, C.B., M.P., vice-president.

M. WALLON, the new French Minister of Public Instruction, is an old University man; he was for years Professor of History in the Normal School. His appointment has given great satisfaction to the French savants, and the reception which he had on his installation on the 13th inst. was something more than a formal congratulation.

AN interesting study has lately been made by Prof. Holden, of the Washington Observatory, on the observations of Sir William Herschel upon the satellites of Uranus. It is well known that the latter astronomer sixty years ago announced that Uranus was accompanied by six satellites; but of the existence of four of these there has always been considerable doubt, since no one was ever able to confirm the observations of Herschel. In 1847 Lassell discovered two interior satellites, which were, however, different from those which Herschel suspected; and since that day the four problematical satellites of Herschel have been generally discarded by astronomers. Prof. Holden now brings testimony to the high excellence of Herschel's observations, as, by computing backward, he has shown that probably this distinguished astronomer actually observed the two interior satellites of Lassell (named by him Ariel and Umbriel); but that he was unfortunately prevented from identifying them as satellites because his telescope could not show them on two successive nights. The extreme difficulty of observing these objects makes us wonder at the marvellous skill and patience manifested by the elder Herschel in this laborious research, which was carried on by him from 1787 to 1810.

THE Imperial Astronomical Observatory of Brazil is a dependence of the Central College of Rio Janeiro, and is destined not only to teach practical astronomy to the students, but to make and publish astronomical and meteorological observations. The chronometers of the navy and army are there regulated, and the time is given daily by signal to the city. The building is situated on an eminence within the city, and the Government is now taking measures to improve its scientific character. The director is at present in Europe with a view of procuring such instruments and apparatus as may be adapted to the studies required of the institution. An entire reorganisation of the Observatory is under way, with the purpose of training more thoroughly the persons charged with geologic and geodetic works. There is also an observatory at the capital of the province of Pernambuco.

We have received the Catalogue of the Library of the Manchester Geological Society, compiled by Mr. John Plant, F.G.S. We are glad to see that the members of this Society possess so good a collection of works connected with the various departments of geology, and we hope a large proportion of them take advantage of the privilege. Mr. Plant has arranged the books in eleven divisions, which will no doubt facilitate the work of reference, though it seems to us that divisions for works in German, works in French, &c., are unnecessary.

MR. HENRY CHICHESTER HART, B.A., one of the naturalists appointed to the Arctic Expedition of 1875, has published an enumeration of all the flowering plants and ferns

known to occur in the Arran Islands, Galway Bay. The flora of

the whole of the west of Ireland is extremely interesting on account of the south-west European types it includes, indicating the possible former existence of a connection between the British Islands and the Continent. The Arran Isles flora includes no endemic species, and, on account of their peculiar geological formation, the numbes of species is scarcely so large as might otherwise have

been expected. The formation belongs to the Upper Carboniferous Limestone, and consists of deeply-fissured platforms or terraces, paved with large flags. Mr. Hart's list contains 372 species, including Dabeocia polifolia and some other West European forms. Ajuga pyramidalis and Helianthemum canum are at home here, and Gentiana verna is reported to be one of the commonest weeds. One of the principal features of the flora is the luxuriance of the ferns in the deep fissures of the rocks. The true maiden-hair (Adiantum capillus-veneris) is said to be common on all three islands, and often found with fronds two feet long. In the same situations the fronds of Asplenium marinum attain a length of three feet, and those of Ceterach officinarum a foot or more. Mr. Hart himself adds about twenty-five undoubtedly indigenous species to those previously known.

WITH regard to the conservancy and working of the East Indian rubber-trees (Ficus elastica), the yield of which forms one of the most important products of the Assam forests, we learn that there have been three proposals made to Government: the first is that Government should annually sell the right to collect the rubber; the second, that the rubber should all be purchased by Government; and the third, that Government officers should manage the forests. In opposition to this, however, it is said that much of the rubber is brought in from forests by wild and half-subjugated tribes, and still more by tribes that are under no subjection at all; so that conservancy is impossible, and a Government monopoly very difficult. Only two courses seem possible either to allow speculators to make their own bargains with the hill men as they liked, or to enforce an effective Government control. Sir George Campbell considers the latter course to be the right one. The exports of caoutchouc, it appears, which amounted to 21,000 maunds in 1871-72, fell in 1872-73 to 11,000, this decrease being attributed to the closing of the Luckimpur forests with a view to preventing frontier compli cations.

THE quantity of sandal-wood sold in the provinces of Mysore and Curg during the year 1872-73 was 889 tons, valued at 27,8961.

THE growth of beet-root in Belgium for the manufacture of sugar appears to be falling off, owing to its prohibition by landowners and the unwillingness of the farmers to cultivate it in consequence of its exhaustive nature, a crop of beet impoverishing the soil considerably. It is said, however, that if the farmers could act independently, considerable quantities of beet would be grown, for not only would it then be advantageous to them in a pecuniary point of view, but it would furnish them with a new and valuable food for the use of their cattle and horses. In France, on the other hand, the cultivation of beet is being extended, the pulp, after the extraction of the sugar, proving very serviceable for fattening cattle.

"Flora'

"of

DR. R. A. PRYOR intends publishing a new Hertfordshire, and to enable him to make it as complete as possible, he has issued a circular containing lists of plants respecting which further information is needed. Critical species will be thoroughly studied out. Webb and Coleman's "Flora Hertfordiensis" (1849), supplements to which appeared in 1851 and 1859, is a very good work, and the only "Flora" of the county hitherto published; but so much has been done in critical botany of late that it is, in this respect, out of date.

On Friday the 12th inst. an icy cloud passing before the sun exhibited the laws of the formation of halos with an extraordinary precision. The cloud, driven by an upper wind, was travelling at a slow rate from south to north. A partial halo was first seen on the northern edge, developed itself, lasted as long as the cloud, occupied more than 16° north and 164° south