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Le fruit ramassé par un boy, “Il y porte la dent, fait la potassium chlorate. There was also introduced a little starch grimace. Le moindre ducaton serait bien mieux son solution and a small quantity of potassium iodide to serve as a affaire." Notre boy se décide dès lors à porter le fruit au indicator of the completion of a certain amount of work, which was jardinier de " North End Park.” Le végétal confié à la terre the conversion of a known small weight of sodium thiosulphair poussa et donna un arbre, Barringtonia speciosa, qui avait into tetrathionate. The completion of this change was marked atteint 4 pieds de hauteur vers le milieu de l'année 1888. by the appearance of a blue colour in the liquid. The operation
M. A. W. Buckland émettait l'hypothèse que fruit et pumites, was then repeated. comme aussi quelques poissons et serpents appartenant à des In these experiments the amount of substances undergoing espèces jusque-là inconnues dans le pays, et arrivés en même change, when compared with the total amount present, was sa temps, provenaient des parages de la Sonde, et, à la suite de la large that the masses of the substances remained practically grande éruption de Krakatoa en 1883, avaient été portés par les constant during each experiment. Hots jusque sur les rivages de la côte Sud-Africaine.
In such a mixture the condition of equilibriuin may be conIl n'y a plus à douter, je crois, de la provenance des pumites.sidered to be represented by the following equation : Je n'ai rien à dire au sujet des poissons et serpents. Mais pour ce qui est du fruit de Barringtonia speciosa, il me semble qu'on
nHCl + mKCIO; = mHCIO3 + mKCI + (1 - m)HCI, pourrait lui donner une autre origine ou point de départ, et where n is greater than m. diminuer ainsi de beaucoup la durée de sa traversée sur l'océan.
We may then regard the oxidizing material as being liberated by L'arbre Barringtonia speciosa croît
, en effet, à Madagascar, où the reaction of the (n -- ) molecules of hydrogen chloride with je l'ai vu à Tamatave, sur les bords de la mer. Il ne serait the m molecules of hydrogen chlorate so liberated. The prodonc point du tout improbable que le fruit porté par les flots à sence of the m molecules of potassium chloride will produce its Port-Élisabeth provint de la grande ile Africaine. En même specific effect (in this case acceleration) on the rate of reaction. temps que je signalais l'arrivée sur nos plages Malgaches des So that out of the n molecules of hydrogen chloride employed pumites de Krakatoa, en Septembre 1884 et en Février 1885 only n - m are actively engaged in liberating oxidizing material, (Cosmos, nouvelle série, No. 12, p. 320), j'envoyais en Europe the rest having been employed in saline decomposition. If such divers spécimens de ces pumites ramassés sur la plage de Tama. be the case, it ought to be possible to obtain a similar rate of tave. Parmi les spécimens adressés à la Société Nationale oxidation by taking m molecules of hydrogen chlorate instead of d'Acclimatation de France s'en trouvait un dans lequel s'était potassium chlorate, and then reducing the hydrogen chloride logé une partie de végétal, -une fleur, si je ne me trompe, d'une used from n to (n - m) molecules. "If we then add the espèce de Terminalia, qui croît aussi à Tamatave sur les bords molecules of potassium chloride we should then be able to build de la mer (Bulletin de la Société Nationale d'Acclimatation de up a system similar to what is obtained in the former case as France, Décembre 1884, p. 983).
regards saline equilibrium. The following results were obtained Un fruit de Barringtonia speciosa arbre qui, comme je l'ai by this method of procedure. fait remarquer, croît au bord de la mer sur la côte orientale de
The numbers signify millionth gram molecules per ca, and Mauagascar, a très bien pu, de même, prendre " passage " sur the rates, R, denote the number of millionth gram molecules of une pumite ou un banc de pumites atterrées sur la plage Malgache ; cio; decomposed per minute in each cc. puis, à la première haute marée, avoir cinglé sur ce " transport
A. nHCl + mKCIO, d'un nouveau genre vers la côte Sud-Africaine, poussé par le I. n = 18 x 65'11
gives R = Oʻ0104 Courant Indien, jusqu'à son arrivée à Port-Élisabeth, où il a m = 6 x 5145 B. (n = 2HCl + nHCIO, + mKCI enrichi le “North End Park" d'un nouvel arbre exotique.
gives R = 0 0105
A. „HCl + mKCIO,
gives R = 0'00554 Madagascar y gagnerait de pouvoir être considérée comme une
m = 6 x 515 grande “ escale,” établie par le Dieu Créateur et Ordonnateur
B. (n = m)HCI + mHCIO, + mKCI des Mondes, pour le service des " Messageries maritimes " de la
gives R = 0'00555 Nature entre les Archipels de la Malaisie et la côte Sud
A. nHCl + mKCIO, Africaine.
III. n = 15 x 65'11
gives R = 0.00195 Veuillez agréer, Monsieur le Rédacteur, les respectueuses
2 X 515
B. (n = m)HCI + mHCIO, + mKCI salutations de votre humble serviteur,
gives R = 0'00191
W. H. PENDLEBURY.
On the Use of the Word Antiparallel.
After reading Mr. James's note, I looked out the reference A Marine Millipede.
quoted by him from Stone's Dictionary in the "Acta ErudiBritish naturalists, especially such as work on the south torum.” Stone's reference is quite correct, and, as the passage is coast, will hear with interest that Mr. J. Sinel has lately found an interesting one, it may be well to quote it in full. It occurs in Jersey the very curious marine Millipede, Geophilus sub- in an article by Leibnitz treating of the catenary. maritima, Grube (Verh. d. schles. Gesellsch., 1872). Dr. Latzel, * Tangentem ducere ad punctum lineæ datum C; in AR boriof Vienna, tells me that the specimens differ somewhat from the zontali per verticem A sumatur R ut fiat OR æqualis OB
datæ type, and probably constitute a well-marked variety. Some et ipsi OR ducta antiparallela CT, occurrens axi AO in T, erit examples were found close to the low-water mark of very low tangens quæsita. spring tides, where they could not be exposed more than two days in a fortnight.
The Geophilus occurs associated with two or three beetles, of which at least one appears to be new, and with a remarkable Cheliser which is probably identical with Obisium littorale,
C a new species described by Moniez from Boulogne, in this month's Revue Biologique, or with the doub:ful species 0. mari. timum cf Leach (Zool. Miscellany, iii. 1817).
Mr. Sinel's crowbar, a tool the naturalist mahes too little use of, is doing wonderful service.
D. W. T. December 2.
T A Case of Chemical Equilibrium. During some experiments made in connection with a research recently laid before the Royal Society, we came upon an in " Antiparallelas compendii causa hic voco ipsas OR et TC teresting case of chemical equilibrium.
si ad parallelas AR et BC faciant non quidem eosdem angulos The object of the research was to determine the rate of sed tamen, complemento sibi existentes ad rectum, ARO et evolution of oxidizing material liberated, under varied condi-BCT." tions, in a solution containing dilute hydrogen chloride and The following quotation is given in Murray's "New English
Dutionary." and is assigned to the year 1660 :-" To take the REPORT ON THE MAGNETICAL RESULTS OF oppusite course and to provide our remedy anti paralld to their Hisease." Here it seems intended to convey the idea of "parallel
THE VOYAGE OF H.M.S. "CHALLENGER.” and in the opposite sense." in Barlow Mathematical Dictionary” (1814), the modern It will be remembered by readers of the “Narrative of
the Voyage of H.M.S. Challenger," that Vol. II., meaning is given, and the old error as to the ratios of the published in 1882, contained a report of the magnetic zamenis of the sides of the triangle is pointed out.
observations made in that vessel in considerable detail. la Ress': "Cyclopædia" (1819) the modern meaning is given, It has, however, been reserved to the present year for a
remath is added that Leibnitz used the word in the sense full discussion of the Challenger observations and their aplained above; as no reference is given, we cannot tell whether the writer meant that he habitually used it or only in bearing on our existing knowledge of terrestrial magthe article on the catenary.
E, M, LANGLEY.
netism to be made, and the following is an abstract Bellori.
of the final Report about to be published in Vol. II.,
"Physics and Chemistry of the Voyage of H.M.S. A Surviving Tasmanian Aborigine.
Challenger." Ix your issue of November 14 (p. 43), you refer to the paper elements by curves of equal value has, since 1700, when
The method of representing the values of the magnetic on & Mrs. Fanny Cochrane Smith, who lays claim to be the last Halley published his map of the declination, found surviving aboriginal Tasmanian. Since your note appeared, I general favour; for in succeeding years we find Mounhave read a report of the paper published in the Hobart Mercury tain and Dodson, Churchman, Yeates, and Barlow, also of September to last, and think my view on the claim may be published maps of the same magnetic element. uf some interest to your readers.
In 1819, Hansteen added maps of inclination to the Mr. Barnard states that he knew Mrs. Smith forty years ago declination for certain epochs, and in 1826 produced a when she was seventeen years of age, and that during the period chart of isodynamic lines, revised in 1832. which elapsed since then until she called upon him shortly before Following Hansteen, there appeared, in 1840, Gauss he wrote his paper, he had not known of her whereabouts. In and Weber's atlas, the result of calculations from about favour of the claim I can only find that she has, with apparently eighty-four observations distributed over the world, preone exception, always been reserred to officially as a pure-bred senting a remarkable approach to the truth, even when alergine, and that Parliament appears to have voted her grants viewed in the light of our comparatively extended knowon two uccasions (in 1882 and in 1884) on account of her unique ledge of the earth's magnetism in the present day. It positum
The objections to the claim may be briefly summarized as may be observed that, if only a fresh magnetic survey of follows:
the regions south of 40° S. latitude were now made, a re(1) From the meagre account given, it appears her hair and calculation of the Gaussian constants might be underumpleaos are both that of half-castes, and we are not supplied taken promising important results. with any other description of her features or stature or pecu Between 1868 and 1876 Sir E. Sabine's “ Contribuliarities so as to be able to judge on the question.
tions to Magnetism” were read before the Royal Society, 12) Beyond the mere statement as to mutual recognition no forming a series of papers on the magnetic survey of evidence is given that the claimant is the same girl Mr. Barnard the globe for the epoch 1842-5. Although the maps acknew foriy years ago at Oyster Cove, nor, indeed, is there any companying these contributions serve as a point of thing to show that this woman is the child, or one of the children; departure for comparison with subsequent maps, an exwell-known views, which quasi fact forms the foundation for the amination of them shows that in Africa and the North and elaim.
South Pacific Oceans there were large blanks from want (3) The woman herself is reported to have no recollection of of observations witnessing, at the age of thirteen, a document sufficiently im. There remained, therefore, a large field for observation, portant to have impressed itself on her memory, and it is and it will now be shown how largely the Challenger somewhat strange that this very document is said to describe her Expedition contributed to the filling up of these blanks, as a tall-caste.
and added to our knowledge of the changes going on in It would, no doubt, be interesting were it to be eventually the magnetic elements in places visited by previous proved that this woman Fanny is a pure-bred aborigine, but for observers. the present Truganina must be considered the last survivor of
The whole of the magnetical results have been emher face
HY. LING ROTH.
bodied with others from every available source in four Lightcliffe, November 23.
charts of the magnetic elements, for the epoch 1880,
which may prove acceptable to magneticians desirous Brilliant Meteors.
of noting the changes in the magnetic elements since Toe brilliant meteor seen at Warwick School and in
1842-5. Cumberland I saw at Folkestone on November 4 a little before The Challenger was not an ideal ship in which to con8. I was travelling slowly from north-west to north, about duct magnetic observations at sea, for she was seldom at 30 abors, and parallel with, the horizon. After travelling some rest from pitching and rolling, and although the errors in fanker and burst. At first it was a beautiful green colour, but the observations caused by the horizontal component of after it had partly burst it was nearly white. I imagined its the ship's magnetism were moderate, and could be colour was through the haze there was in the sky. From what eliminated by “swinging" the ship, those proceeding I saw I at certain it would have been a splendid sight had from the vertical component were large, and necessitated the atmosphere been clear.
P. A. HARRIS. a frequent comparison with normal values on land. But Inchulva, Maidstone, November 27.
by discussing fully a series of observations made in
numerous places in both hemispheres where no trace of Last night, in clouded moonlight, whilst walking here from local magnetic disturbance could be found, the magnetic Newton by the road over Little Dunnow, my attention was condition of the ship was readily determined for any arrested by the glare of what must have been a very bright period of the voyage. As a consequence of this, normal meteor, seen through clouds which formed a general covering. values of the magnetic elements could be obtained in the The quarter in which the light appeared was east by north, at neighbourhood of places known or suspected of being an elevation of about 25, and it lasted a second and a half
. affected by local magnetic disturbance, and the amount There appeared to be three centres of illumination, but these of such disturbance measured with considerable accuracy. may have been only thinner portions of the clouds. The time, nearly as I could get it by comparing my watch by telegraph
This method of detecting local magnetic disturbance, at the village post office this morning, was 22h. 48m. 45s.
" Note published with the "Report of the Scientific Results of the Voyage Slaidburn, Clitheroe, December 2. R. H. TIDDEMAN. of H.M.S. Challenger," Physics and Chemistry, vol. II., Part VI.
was applied to the solitary islands of the ocean visited against similar disturbances elsewhere, reporting any new by the Challenger, and the following are some of the discoveries as he would a rock or shoal. principal results.
Large as was the Challenger's contribution to the At Madeira there was a difference of 74° in the ob- magnetic charts for 1880, it will be readily understood served inclination between observations made at i foot that it required considerable reinforcement from other and 31 above the ground; and at Santa Cruz, Tenerife, sources, as their construction was dependent on observathe inclination was 21° in excess of the normal observed tion alone. Every available observation between the years in the ship
1865-87 was utilized. Beyond the published sources of inforIt was at Bermuda, however, that the most remarkable mation on this subject may be mentioned the observations results were obtained. For some years previously, ob- made on the east coast of Africı by the officers of H.M.S. servers in different parts of the group had obtained very Nassau in 1874-76, and on the west coast of Australia in different values of the declination, and our men-of-war 1885-86 by H.M.S. Meda. Also the ser observations when swinging for deviations of the compass had found between Australia and Cape Horn of the declination in constant errors for every direction of the ship's head H.M.SS. Esk, Pearl, and Thalia, between 1867-87, not which were peculiar to Bermuda. It could only, therefore, forgetting those of the New Zealand Shipping Company's be by a properly equipped expedition like that of the vessels in 1885-86. Challenger, and systematic observation, that the imme To combine this twenty years' observation usefully, a diate cause of all this local magnetic disturbance could somewhat extended knowledge of the distribution and be traced.
amount of secular change became a necessity. Generally For this purpose the declination was observed at speaking, it is only at fixed observatories that this seventeen stations, the inclination at ten, and the intensity element of terrestrial magnetism is known with precision, at seven. Combining these observations with others made for, as already shown, observations a few feet apart often by previous observers, it was found that between the give very different results. In the more frequented parts Governor's house at Mount Langton and the lighthouse of the earth this secular change is approximately known, on Gibb's Hill, there is a disturbing magnetic focus especially in the United States, where valuable work has attracting the north-seeking end of the needle with a been accomplished. force considerably in excess of that due to the position One great object of the voyage of the Challenger was of Bermuda on the earth considered as a magnet. The to visit certain unfrequented positions where previous obnormal values of the magnetic elements were obtained servers had been, rather than the beaten tracks. Thus by swinging the ship at sea 15' south of the green outside Ross's position of 1840 on St. Paul Rocks was visited, the dockyard. The difference between the observed and the secular change during thirty-three years obtained. declination at Clarence Cove and Barge Island was 5° 44'. Then Tristan d'Acunha, an important station situated in The greatest difference in the inclination was l° 47', and mid-ocean, rarely visited for magnetic purposes. At in the vertical force + 0*314 (Brit. units).
Kerguelen Island, anɔther of Ross's positions, observaLocal magnetic disturbances were also noted at St. tions of all three principal magnetic elements were made, Vincent, Cape de Verde Islands, Tristan d'Acunha, Ker- and the secular change found approximately. guelen Ísland, Sandwich Islands, Juan Fernandez, and In the Indian Ocean generally, north of 30° S., the Ascension, but not at St. Paul Rocks.
secular change of the declination rarely exceeds i anBy applying the same method of obtaining normal nually, but at Kerguelen Island the westerly declination values at sea, and observing on other adjacent solitary is increasing at least 5' annually. islands such as St. Helena, similar effects result, and the It was, however, from two positions on the homeward following general conclusions seem to be supported by voyage that the most novel and remarkable values of the fact with regard to local magnetic disturbance: -- secular change were obtained --Sandy Point, Magellan
(1) That in islands north of the magnetic equator, the Straits, and the Island of Asce sion, with its adjacent north-seeking end of the needle is generally attracted waters. vertically downwards, and horizontally towards the higher At Sandy Point, with the horizontal force nearly parts of the land ; (2) south of the magnetic equator the stationary, and the declination decreasing 3° annually, it opposite effects are observed, the north-seeking end of was hardly suspected until 1876, when the Challenger the needle being repelled : in both cases by an amount visited the place, that the inclination was apparently above that due to the position of the island on the earth changing ii' annually. Comparing the Challenger's considered as a magnet.
results by swinging near the Island of Ascension with Interesting as these conclusions may possibly be from Sabine of 1842-5, the following values of the secular a scientific point of view, they are of real importance in change are obtainer: declination increasing S'annupractical navigation. Navigators have asserted that their ally; south inclination increasing 14. compasses were disturbed when passing the land in From these results the notable fact is made evident, that certain parts of the world. We learn from the Challenger the north-seeking end of the needle is found to be moving observations that within 5 feet from the soil the greatest in opposite directions, downwards at Sandy Point, and magnetic disturbance did not exceed 30 in the declina- more strongly upwards at Ascension. Extending the tion and 24° in the inclination. Remembering the law of inquiry into the surrounding seas and countries, it was magnetic attraction and repulsion, it is impossible that found that these opposite movements of the needle were a compass in such case could be disturbed in a vessel not confined to the spots where they were discovered. passing the land at the ordinary distance. In point of The author of this Report, after having discussed his fact, it has been shown that it is to submerged magnetic collection of a large number of observations of the land comparatively near the ship's bottom that the dis magnetic elements for all parts of the world-in many turbance of the compass is due. The remarkable instance cases extending over several years-obtained approximate at Cossack in North-West Australia may be cited in sup- values of their secular change for the epoch 1840-8o. port of this conclusion. Thus in H.M.S. Meda, sailing on a These several values were weighted according to their line of transit of two objects on land for a quarter of an relative accuracy, and entered on naps against the places hour in 8 fathoms of water, it was found that the compass of observation. Lines of equal value were then drawn was steadily deflected 30°, no visible land being nearer for each element, and the following general results obthan 3 miles.
tained with regard to the movements of the north-seekGreat as the gain must be to the navigator to be thus ing end of the needle. warned of a formidable danger in certain places, it also i. Declination. The principal lines of little or no lays upon him the important duty of being on his guard change were found to take the course from St. John's,
Newfoundland, to the West Coast of Africa, near Cape South Pacific. The route lay from Wellington, N.Z, to de l'er'e emerging near Cape Palmas, and then to Cape Tongatabu, and Fiji, from the Admiralty Islands to Japan, Town, thence curving upwards near Mauritius, down and thence in mid-ocean from nearly 40° N., through the wards south of Cape Leeuwin, again upwards through Sandwich Islands and Tahiti to 40° s., nearly at right Adelaide and Cape York to the vicinity of Hong Kong. angles to the curves of equal magnetic inclination. A second line passed from Sitka through the western During the voyage much experience was gained as to portion of the continent of North America, striking South the usefulness of the Fox circle as an instrument for use on America near Callao, then following the trend of the coast board ship at sea, the general result being that valuable in a point near the western entrance to Magellan Strait. work may be done with it if frequently compared with
The foci of maximum value of change were found : the absolute instruments on land, and the instrument ittelween Scotland and Norway, change about 9' an mounted on a gimbal stand prepared to withstand the mualls, needle moving eastward ; (2) on the east coast vibrations caused by the engines of the vessel. of Brazil, needle moving westward about 8. Minor foci Although on the general question of the secular change were also found : one near Kerguelen Island, the other of the magnetic elements much has been already written in the South Pacific. Another focus apparently exists in this Report, there yet remain some important points in Alaska. The general tendency was for the values of which demand further discussion. the change to decrease gradually from the foci to lines of As to the causes of the secular change various no change.
hypotheses have been advanced. Thus in the early part 2. Inclination.-Similarly to that of the declination, of the last century, Halley considered the change was there are lmes of no change, two principal foci of maximum chiefly caused by a terella with two poles or foci of secular change, but only one minor focus. The lines of intensity rotating within and independently of the outer TL change are not so clearly defined as those for the shell of the earth, which also possessed two foci of decimalion, data being still wanting. The principal foci intensity, the axes of the two globes being inclined one of maximum change in the inclination were found : (1) to the other but having a common centre. near the Gulf of Guinea, between Ascension and St. Again, Hansteen at the beginning of the present Thome, which may be called the Guinea focus. Here century concluded that there are four poles of attraction, the north-seeking end of the needle was moving upwards and computed both the geographical positions and the about 15' annually. (2) in the latitude of Cape Horn, probable period of the revolution of this dual system of and about &o W. long. This may be called the Cape poles or points of attraction round the terrestrial pole. Hurt focus, and the annual change was 1', needle In later years Sabine considered the secular change to leing drawn downwards. It must be distinctly under- be caused by the progressive translation of the point stood that both the positions and values of the change of attraction at present in Northern Siberia, this point are only approximate, and only the general features in of attraction resulting from cosmical action. Walker the angular movement of the freely suspended needle also agreed with Sabine as to the cosmical origin of the are to be accepted, as clearly shown by this investigation. change.
3. Magnetic Intensity.- in the horizontal force, the Later still, Balfour Stewart gave reasons for attributing annual change (B.U.) was about - oʻ002 near Cape Horn, the secular variation to the result of solar influence of a whilst between l'alparaiso and Monte Video the focus of cumulative nature. greatest change was about - 0017. Again, on the west Keeping in view these hypotheses, and recalling the coast of Portugal a focus of + o‘009 (B.U.) occurred. chief results of observation during recent years, how do
Turning to the vertical component of the eartb's they accord ? intensity, some remarkable results were observed. At Observation generally points to the fixity of the magthe Cape Horn focus an annual change of 0'055 (B.U.) netic poles--or two limited areas where the needle is was found in the vertical force, the north-seeking end of vertical-in respect to the geographical poles. Again, the needle being drawn downwards, the change diminish in Siberia there is little or no apparent translation of the ing in value until the zero line extending from Callao greatest point of attraction in that region, and the North across the American continent to the west coast between American focus of intensity is probably at rest. Bahia and Rio de Janeiro, and then taking a south Thus the results of observation in recent years are not casterly course north of Tristan d'Acunha, was reached. favourable to hypotheses founded on the translation of Northward and eastward of this zero line there were the poles or foci of magnetic intensity. found increasing values in the annual change in the Let the terms blue and red magnetism be adopted, and upuurd vertical force acting on the north-seeking end of the movements of the red, or north-seeking, end of the the needle until the Guinea focus was reached, where its needle alone be considered. full value was increasing 0'025 annually: From the The question arises, What have recent observations Guinea focus to Northern Europe, Asia, and the Atlantic offered us instead? They tell us that near a line drawn seaboard the change gradually decreased in amount. from the North Cape of Norway across the Atlantic to There were signs of minor movements in the north-seek-Cape Horn lie some of the foci of greatest known secular ing end of the needle in China, Mexico, and the United change. It was also found that at the Cape Horn focus States.
of vertical force the needle was moving downwards, or One of the chief factors in the compilation of the pre- there was the equivalent to a blue pole of increasing vioualy mentioned maps of the three elements for the power of attraction, the freely suspended needle being epoch 1880 were the observations taken in the Challenger, attracted towards it over an extended region around. At and these were reduced to the common epoch by means the Guinea focus there was the equivalent to a red pole of the investigation of annual change to which reference of increasing power of repulsion, the freely suspended has just been made.
needle being repelled over an extended region of unIt may be truly said that the Challenger's track was defined limits. The action of these two poles apparently studded with magnetic observations. After successfully combine to produce a focus of considerable angular traversing the Atlantic Oceans in varying directions, the movement in the horizontal needle near Brazil. three magnetic elements were obtained by swinging, in In China there is a minor blue pole of increasing power probably the most southerly position since the days of attracting the needle over a large area. Ross in the Erebus and Terror, in lat. 63° 30' S., and With apparently small secular changes in Siberia, and lopg, goʻ 47' E. But the most valuable part of the con- the horizontal needle moving somewhat rapidly to the tnbutions to terrestrial magnetism obtained in the Chal-eastward at the focus of change in the declination in the lenger were the observations made in the North and German Ocean, and similarly to the westward in Alaska,
analogy points to the probability of there being a decrease star shower. That the individuals are really minute in the vertical force in the high latitudes of North proved by the fact that, while the total mass of a large America, or the equivalent to a red pole of increasing swarm, like that producing the November meteors, is so power repelling the needle for a large area around it. small that there is no perceptible influence on the motion
The variations in the vertical force at and about these of the planets, the number of separate individuals .. poles or foci of attraction and repulsion at different epochs almost infinite. It is established that the Leon are not yet sufficiently determined, but if the hypothesis of swarm must be hundreds of millions of miles in length translation be given up, it is not unreasonable to suppose and some hundreds of thousands of miles in thickness that the secular changes in the declination and inclination and in the densest part of the Bielid swarm, passa are chiefly dependent upon changes in the relative power through in 1885, the average distance of the individuals of these polcs.
from each other was about twenty miles. No satisfactory explanation has yet been given of the Further, it is now acknowledged that comets are there remarkable changes in the earth's magnetic force as selves meteoritic swarms, and Mr. Lockyer has lately measured on its surface, and suggestions are only possible brought forward spectroscopic evidence that the fixed in the present instance.
stars and the nebulæ are similar to comets in their con The voyage of the Challenger has shown that local stitution. magnetic disturbance is found in the solitary islands of The question therefore immediately presents itself, 18 the sea, although surrounded by apparently normal con the size of a meteoritic shower, on reaching the earth ditions, similar to that on the great continents. It has also surface, ever comparable with that of a meteoritic swar, been suggested that the magnetic portions of these islands as manifested by a shower of shooting-stars? causing the disturbance may possibly “have been raised During the present century nearly 300 meteoritic fall4 to the earth's surface from the magnetized portion of the on the earth's surface have been observed, and on only á earth forming the source of magnetism," and tending to single date, namely August 25, 1865, has there been prove Airy's conclusion that the source of magnetism observed a fall on two distant parts of the earth on the lies deep."
same day. On that date stones fell at Aumale in Algeria In view, therefore. of past geological changes and those and at Sherghotty in India ; but as the times of fall differec now in progress, it may fairly be conceived, not only that by about eight hours, and the stones arrived from different large changes have likewise occurred in the distribution directions, it is more than probable that the coincidence of the magnetic portions of the earth appearing here and of date was accidental. Hence we must infer that i there on the surface and producing local magnetic dis- swarm of meteorites, as far as actual observation of turbance, but that there are others of a more progressive tangible objects goes, far from being hundreds of millions character below the earth's surface which are only made of miles long, with individuals a few miles apart, is a manifest by the secular change observed in the magnetic comparatively small group, separated from its neighelements. This conception with regard to secular change bours, if it has any, by a distance comparable with the is not intended to exclude the view that solar influences earth's diameter. may have a small share in producing the observed The extent of surface over which meteoric stones have phenomena.
been picked up after some of the best known and most In conclusion, it may be remarked that they who widely spread falls is given in the following list :would fully see the substantial gains to terrestrial magnetism which have been obtained by the voyage of the
Limerick, 3 miles long. Challenger must refer to the original of this abstract
Mocs, 3 miles by o 6 mile. Report, with its plates and charts of the magnetic elements.
Butsura, 3 miles by 2 miles. Subsequent research may add to, qualify, or reverse
Pultusk, 5 miles by i mile. the conclusions drawn from the observations, but the
L'Aigle, 6 miles by 2'5 miles, observations will probably retain a long-abiding value
Barbotan, 6 miles long. to magneticians.
E. W. CREAK.
West Liberty, 7 miles by 4 miles.
Weston, 10 miles long.
Hessle, 10 miles by 3 miles. OF METEORITES IN THE DESERT OF
New Concord, 10 miles by 3 miles. ATACAMA.
Castalia, 10 miles by 3 miles.
Khairpur, 16 miles by 3 miles. is now universally acknowledged both that meteorites
As far as I have yet been able to ascertain, the greatest ever they are, have an extra-terrestrial origin. It is observed separation has been sixteen miles. In the case further asserted that a meteoritic fireball and a shooting- of Macao, Cold Bokkeveldt, and Pillistfer, wider spreads star are only varieties of one phenomenon. Indeed, after have been chronicled, but later information has shown it is once granted that a meteoritic fireball is produced the inaccuracy of the earlier statements. by the passage through the terrestrial atmosphere of a As regards the meteoric irons, there have only been dense body entering it with planetary velocity from with nine observed falls since the year 1751 : in seven of them out, and that shooting-stars have an extra-terrestrial only a single mass was found; in the remaining two there origin, it is a very fair assumption that a shooting-star was in each case a couple of masses, not more than a is likewise a dense body rendered luminous during its mile apart. There is thus no recorded instance of an atmospheric flight.
observed shower of meteoric iron. The most convincing One great objection to this assertion is that, again and proof of the actuality of such showers is furnished by the again, showers of hundreds of thousands of shooting- masses which have been found in the Valley of Toluca, stars have taken place, during which no heavy body has in Mexico; their existence had been chronicled as early been observed to reach the earth's surface. The only as the year 1784, yet in 1856 it was still possible to colknown case of the arrival of a meteorite during a shooting- lect as many as sixty-nine. When etched, they show the star shower has been that of Mazapil, on November 27, Widmanstätten figures in the most excellent way, and in 1885, and that single coincidence may possibly be the their characters they are typical meteorites. Belonging, result of accident. A sufficient explanation of this diffi- as they do, to a single type, they lead to the conviction culty, however, is to be found in the small size of the that they are the result of a single shower. But the individuals which produce the appearance of a shooting- region over which the fall took place is not large; the