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metrical Survey." The author com- posed by the author to be produced menced by noticing the reasons which by the granite existing in Mount Sorinduced him to undertake the expe- rel in Leicestershire. Captain Ķ. riments forming the subject of his stated that he had learned with pleapresent report ; and afterwards pro- sure, that M, Biot’s results with receeded to describe the apparatus em- spect to the acceleration of the penployed. The operations at each sta- dulum between London and Unst ation were then minutely detailed, greed with his own to within 0.6'. and the results stated at length, and July 1:- A paper was read, on the illustrated by numerous tables. causes which influence the direction

For the latitude of London, the of the Magnetic Needle, by Captain length of the pendulum vibrating se. J. Burney, R. N. The author, after conds, on the scale forming the basis relating a variety of experiments, apof the Trigonometrical Survey, was peared to conclude, that the compass stated to be 39.13792 inches. is governed partly by polarity, which

For the latitude of Unst, 39.16939 he considers as created by motion, Portsoy,

89.15952 and the primary cause of the needles Leith Fort,

89.15347 pointing north and south, and partly Clifton,

39.14893 by attraction, which is inherent in Arbury Hill,

39.14043 matter; the former of which is con. Shanklin Farm, 39.13407 stant, the latter variable. On these

The calculations of the latitude of principles the author attempted to each of these stations were then given explain why the needle is most liable at length. The latitude of Arbury to be disturbed in high latitudes by Hill, which had been supposed erro. attraction, the obliquity of the plane neous, was found by Captain K. to be of the earth's rotatory motion to the correct. The whole was concluded horizon being here greater, and hence with some observations on the figure the polarity of the needle diminished. of the earth.

At this meeting also a paper was It appeared from this report, that read by Arthur Jacob, M.D. of Dubexcepting the allowance for the height lin, giving an account of a new memabove the level of the sea, the error brane discovered in the eye. The in the vibrations of the seconds pen- author described a delicate transpadulum at any particular station did rent membrane covering the externot amount to roth of a vibration, nal surface of the retina, and united which is about equal to the 400,000th to it by cellular substance. The papart of the length ; consequently that per was concluded by pointing out ihe amount of gravitation could be the best method of detecting and exdetermined to this degree of ac- amining it. curacy. Now this is so near as to The titles of the two following paindicate the different degrees of den- pers were also read, but from the nasity of the materials constituting the ture of the subject did not admit of substrata of the different stations in being read in detail. “ On the Thea country selected for experiment. ory of Capillary Attraction," by J. Hence Captain K. concluded, that Ivory, Esq.; and “on a New Method minute differences in density, indi- of solving Numerical Equations of cated by the pendulum, are often to all Orders by continuous Approxi. be referred to irregularities of attrac- mation,” by W. G. Horner, Esq. tion : thus the sudden increase of The society then adjourned till gravitation at Arbury Hill, was sup- November.

ROYAL INSTITUTE OF FRANCE. motive caused the French Govern

ment to seize with avidity the opporIn the public sittings of the 22d of tunity offered, two years ago, of seeMarch 1819, a notice was read by M. ing this operation, already so grand, Biot, on the continuation of the la- extend itself towards the north to bours undertaken to determine the nearly equal extent, in uniting with a figure of the earth, and upon the re. portion of the same meridian, which sults of the experiments on the pen. stretches from the southern coast of dulum, made in 1817, at the Shet. England as far as the Shetland Isles, land Islands, by himself and others. to a higher latitude than St Peters

At first, it was merely known that burgh ; a portion which the scientific the earth was of a round figure, men of England have been now twen. which was easily ascertained by the ty years occupied in measuring. circular form which its shadow pre- - In order to terminate this immense sents when projected on the moon's arc, which comprehends almost the disc during an eclipse. Newton af. fourth part of the distance from the terwards discovered, by his calcula. equator to the pole, there remained no. tions, that it was not completely thing, last year, but to construct some round, but somewhat flattened at the triangles between the Shetland Isles poles, and protuberant at the equa- and Scotland, by the medium of the tor. The methods of observation, Orkneys, and to connect the operayet imperfect, have, after great diffi- tions of the English and the French culty, established this truth, which has at the point of junction, Dunkirk, by been at last obtained by measuring means of a system of combined opedegrees of the meridian under the rations, in which the instruments emmost distant latitudes, namely, at the ployed by the observers of the two equator and near the poles. The nations should be made to co-opefatness of the poles was thus put be. yond doubt. The operations prose- This last labour was executed in cuted for the last fifty years in France, the preceding autumn. MM. Arago England, Sweden, America, and In- and Biot went to receive, at Dunkirk, dia, have succeeded in determining the English observers, MM. Mudge, nearly its precise quantity. The mea. Colby, and Gardner, who brought surement of the arc of the meridian with them the grand astronomical comprehended between Dunkirk and sector constructed by Ramsden, Barcelona, and accomplished with which they had made use of in all infinite precision by MM. Mechain their preceding operations : and the and Delambre, was the foundation up- French, on their part, brought one of on which the new system of French their repeating circles. measures was constructed. The desire At Dunkirk this fine instrument of communicating greater precision was, by the desire of the observers, to these results, caused this first arc placed within the marine arsenal. : to be prolonged across Spain as far The English brig the Investigator, as the Balearic Isles *; and it became wbich had conveyed it thither, was a part

of an immense triangle above also to bring it by the docks to the the Mediterranean. In fine, the same place where it was to be employed,

Under the name Balearic, we have followed the ancient, and the latest of the modern geographers, in including not merely Majorca and Minorca, but Ivica, with its contiguous, cluster of islets, of which Formentera, where these geodetical operations were prosecuted, is one. Ivica, lowerer, with its dependencies, constitutes the « lles Pithiuses" of M. Biot.

rate.

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and remain there ready to take it other method, which employs the
back. The French Mathematicians measure of a pendulum, had, toge-
placed their little repeating circle at ther with the preceding, been prac-
a short distance off, in a shed which tised on all the points of the arc. An
the administration of marine had di- account had last year been given, ofa
rected to be constructed for them. tour made in England, Scotland, and
There, owing to a continuation of the Shetland Isles, to carry the
good weather, so little time was left ratus of the pendulum over the whole
for relaxation, that all the observa. extent of the English arc. The English
tions were finished in fifteen days; government, which had favoured this
and when completed, were found to operation, naturally desired that it
agree in a surprising manner, if the should be executed, in like manner,
different nature of the processes be by an observer of their own nation.
considered; and what is still more for- Captain Kater, member of the Royal
tunate, they were found also to ac Society London, an experimentalist
cord perfectly with those which M. singularly exact, and author of an ex:
Delambre had formerly made in the cellent memoir on the length of the
same place, at the commencement of pendulum vibrating seconds in the
his operations ; whence results the latitude of London, was deputed for
double assurance, that the arcs of this purpose. Mith much precaution,
France and England are thus per- he conveyed to Edinburgh and the
fectly connected with each other; Shetland Islands, a solid pendulum,
while the observations made on the of an invariable form, the diurnal rate
other points of the two arcs, by simi- of which he had previously determin.
lar processes, afford all the precision ed at London ; and the oscillations of
which can be desired.

which he had also observed in these As it was expedient that the point different places. It is the same operaof junction of the English and French tion which Capt. Freycinet was to exoperations might always be re-ascer. ecute, in his voyage round the world, tained, MM. Arago and Biot resol. with pendulums constructed under ved to erect some lasting monu- the direction of M. Arago. Capt. Kater ment. The city of Dunkırk freed was received at the Shetland Islands them from this care. A little marble by the same Mr Edmonstone who had column, surmounted with a spire, is received M. Biot with such obliging to be erected in this place, and a short hospitality two years before. inscription will record the object of made his observations in the same the operation, with the names of the place where M. Biot did, with the observers of the two countries. At same assistance and with the same acthe Shetland Isles, the extremity of commodations. The observations of the great arc has been marked in like Captain Kater have been found 10 manner, in the garden of Mr Edmon- accord in a remarkable degree with stone, by a little monument which he those of M. Biot, as was ascertained has caused to be erected in the place by mutual comparison. Having thus where the observations were made. the lengths of the pendulum mea. In Spain, in the isles called Balearic, sured by an uniform process upon the tbe southern extremity of the arc is same meridian from Formentera, the consecrated by a cross.

most southerly of the Balearic Isl. These operations refer to the first ands, to Unst, the most northerly of the methods by which the figure of of the Shetland Islands, and not onthe çarth may be determined. The ly in these two islands, and in a great

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number of intermediate points, the geography, which assigns to each tribe fatness of the earth can, by these of plants their height, limits, and clilengths, be determined with great ex. mate. The terms alpine plants, plants actness. The amount resulting is of hot countries, plants of the seafound to be exactly the same as that shore, are to be found in all landerived from the lunar inequalities, or guages, even in those of the most safrom the comparison of terrestrial de vage nations on the banks of the Oro. grees measured at very distant lati- noko, and prove that the attention tudes ; so that all these methoils, so of men has been constantly fixed on different in their progress, so distinct the distribution of vegetables, and on in their processes, definitively ter- their connexion with the temperaminate in this one result the fatness ture of the air, the elevation of the of the earth; namely, the excess of soil, and the nature of the ground the equatorial above the polar radius; which they inhabit. It does not rethe excess of the former above the quire much sagacity to observe, that latter amounting to a quantity inter on the slope of the high mountains of mediate between gir and sis. The Armenia, vegetables of a different la. difference of these extreme values, titude follow each in succession, like between which the truth lies, will the climates, superimposed, as it were, hardly give a hundred toises, more or upon each other. less, on the half of the axis which The vegetables, says M. Humboldt, passes through the poles of the earth; which cover the vast surface of the and from the number and exactness globe, present, when we study their of the diversified observations by natural classes or families, striking which this truth has been establish- differences in the distribution of their ed, there can no longer be room for forms. On limiting them to the coundiscussion on the subject.

tries in which the number of the species is exactly known, and by divid.

ing this number by that of the glu. Alexander Count Humboldt sub- maceæ, the leguminous plants, the mitted to the Institute a curious pa labiated, and the compound, we find per, on the laws observed in the dis- numerical relations which form very tribution of vegetable forms over the regular series. We see certain forms globe. Botany, long confined to the become more common, from the description of the external forms of equator towards the pole, like the plants, and their artificial classifica. ferns, the glumaceæ, the ericeæ, tion, now presents several branches of and the rhododendra. Other forms, study, which place it more on a foot on the contrary, increase from the ing with the other sciences. Such poles towards the equator, and may are the distribution of vegetables, ac. be considered in our hemisphere as cording to a natural method founded southern forms : such are the rubiaupon the whole part of their structure; ceæ, the malvaceæ, the euphorbiaceæ, their physiology, which displays their the leguminous, and the composite internal organization; their botanical plants. Finally, others attain their

• For the convenience of such of our readers as have not made descriptive botany a particuJar study, we shall here subjoin the translation of the names of some of the most common plants which characteristise the tribes or families most frequently the subjects of discussion in Baron Humboldt's memoir: Juncia (rushies ;) cyperacea (hard or moor grasses, cottongrass ;) gramineæ (corn, grasses ;) composilæ (dandelions, thistles, sunflower ;) leguminosa or papilionaccæ (reiches, pease, clover ;) rubiaccæ (rennet, madder ;) euphorbiaceæ (sunpurge, dog's mercury ;) labiata (mint, thyme, rosemary;) malacca (mallows, hollyhock ;) maximam even in the temperate zone, Lapland there are only 497 phaneroand diminish also towards the equa- gamous plants ; among which are 124 tor and the poles ; such are the la. glumaceæ, 58 composite, 14 legubiated plants, the amentaceæ, the minous, 23 amentaceous, &c. cruciferæ, and the umbelliferæ. The Mr Pursch has made us acquaint. grasses form in England 1-12th, in ed with 2000 phanerogamous plants France 1-18th, in North America which grow between the parallels of 1.10th, of all the phanerogamous 35 and 44° ; consequently, under plants. The glumaceæ form in Ger• mean annual temperatures of 16° and many 1-7th, in France 1-8th, in North 7. The Flora of North America is America 1.8th, in New Holland, ac. a mixture of several Floras. The cording to the researches of Mr southern regions give it an abundance Brown, 1-8th, of the known phane- of malvaceæ and composite plants; rogamous plants. The composite the northern regions, colder than plants increase a little in the northern Europe, under the same parallel, fur. part of the new continent ; for, ac- nish to this Flora abundance of rhodocording to the new Flora of Pursch, dendra, amentaceæ, and coniferæ. there is between the parallels of Geor. The caryophylleæ, the umbelliferæ, gia and Boston 1.6th, whereas in and the cruciferæ,are in general more Germany we find 1-8th, and in France rare in North America, than in the 1.7th, of the total number of the spe. temperate zone of the Old Continent. cies, with visible fructification. In These constant relations observed the whole temperate zone, the glu- on the surface of the globe, in the maceæ and the composite plants form plains from the equator to the pole, together nearly one-fourth of the are again traced in the midst of perphanerogamous plants; the gluma- petual snows on the summits of mounceæ, the compositæ, the cruciferæ, tains. We may admit, in general, and the leguminosæ, together, nearly that on the Cordilleras of the torrid one-third. It results from these res zone, the boreal forms become more searches, that the forms of organized frequent. It is thus that we see prebeings are in a mutual dependence; vail at Quito, on the summit of the and that the unity of nature is such, Andes, the ericeæ, the rhododenthat the forms are limited, the one dra, and the gramineous plants. after the other, according to constant On the contrary, the labiatæ, the rulaws easy of determination.

biaceæ, the malvaceæ, and the exThe number of vegetable species phorbiaceæ, then become as rare as described by botanists, or existing in they are in Lapland. But this anaEuropean herbals, extends to 44,000, logy is not supported in the ferns and of which 6000 are agamous. In this the composite plants. The latter anumber we had already included 3000 bound on the Andes, whereas the new phanerogamous species enume- foriner gradually disappear when they rated by M. Bonpland and myself. rise above 1800 fathoms in height. France, according to M. Decandolle, Thus the climate of the_Andes repossesses 3645 phanerogamous plants, sembles that of northern Europe onof which 460 are glumaceæ, 490 com ly with respect to the mean temperaposite, and 230 leguminous, &c. In lure of the year. The repartition of

umbelliferæ (carrot, hemlock, chervil

, caraway ;) crucifera (mustard, cresses, radish, lurnip.) The great mass of plants which cover the globe is divided by botanists into prænogamous (those having visible flowers,) and cryptagamous, or agamous (ferns, lichens, mushrooms.)

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