1807.] 
therefore, our duty to intimate what pro- 
gress has been made in this undertaking, 
and to assure them of the certainty oF 
our speedy and complete success. 
Since the 2d of May M. de Laplace 
proposed to continue the meridian to the 
Balearic Islands; and Messrs. Biot, Ara- 
go, and Rodri ouez, the Spanish philo- 
sopher, set out “with instraments on the 
2d of September. 
Daring SJ. Arago’s absence, his place 
8 occupied im the observatory by M. 
Claudé Louis Mathieu, «who was born at 
Macon, in November 1784, and is ex- 
tremely well skilled in astronomical ob- 
servations and calculations. 
As they were also to determine the 
pendulum at 45°, on the 26th of July 
Messrs. Bouvard and Biot made trial of 
the mvariable pendulum of platina in- 
tended to be carried into the different 
points of the meridian. In order to de- 
duce the:simple pendulum from it, ais 
the variations in gravity, they cada 
to oscillate before the pendulum of 
clock, the pace of which was Festa 
well known, and they observed from a 
distance, through a glass, the coincidenc 
of the two pendulums; there was not a 
minute of uncertaimty respecting. the 
time in which they exactiy avreed. 
So early as 1775, M. Turgot, then mi- 
nister, wished to send “. IMieseiar to 
Bourdeaux, in order to have the pendu- 
lum at 45°. His retreat from office pre- 
vented the success of this enterprise; but 
at present we are in possession of much 
more perfect methods. 
M. Biot writes from Barcelona, on the 
2d of September, that he was received 
-in a yery polite manner by the heads of 
the Spanish government. 
On the 4th of October, he writes from ~ 
Tarragosa that the gr ae triangle will 
be easily measured aia, ek middle 
of November and the end of bruary. 
On the 12th of October be set out for 
Valentia, and then proceeded to Cullera, 
where he intended to tix one station. The 
rains still proved an obstacie; but in the 
month of November, the north winds, 
ae are thei prevalent, would clear 
the sky. 
On the 16th of October, the smal!!-ad- 
vice-boat, or brigantine, ioe Mysé iQue, 
which was to carry the astrendyiers to 
tlie island of Ivica, arrived: ‘it’ is un- 
armed, goes with sails and oars, and is 
commanded by a very zealous and expe- 
rienced officer, M. de Vacaro. The pass- 
ports of the British Admualty arrived ; 
and the astronomers were to euibar’ at 
Lalande’s History of Astronomy for 1800. 131 
Denia, fifteen leagues to the south of 
Valentia, From Denia to Ivica the 
distance -is only twenty-five leagues, and 
this vreat triangle w ‘ould be easily made 
in the months of, January and February. 
On the 23d of October, M. Biot’em- 
barked for Ivica, and. returned on, the 
10th of November. In consequence of 
this voyage, it was determined’that the 
port of Mongon, near Dema, should be 
chosen as a station, instead of Cullera, 
and the mountain of Camrey, in the 
island of Ivica. All the trianwles will be 
finished in two months; but the latitudes _ 
will not be observed until the end of the 
year at Formenteva, a smail island in the 
neighbourbood of ‘Tvica, where a base 
will be measured. MM. Chaix has taken 
charge of the post of Mongon; M. de 
Vacaro superintends another station, 
M. de Vaudeuil, at Madrid, M. Biot, 
at Barcelona, M. la Nusse, at Valentia, 
and M. Morand, at Denia, took much 
interest in forwarding the preparations, 
aud furnished every requisite assistance. 
Infinite pains and labour were taken in - 
“preparing the stations; two hundred men 
were employed in cutting a path in the 
rock of Mongon, and sixty men and an 
equal number of mules at Ivica. The 
tents were blown down by a dreadful 
wind from the north; but at last, on the 
7th of December, all the reflectors and 
signals were placed. M. Arago is 
indefatigable. 
Thus the sciences have suffered nothing 
by the war. The-Royal Society of L ondoa 
requested, through the mediem of the 
French Institute, the liberty of a British 
astronomer, who was a prisoner in 
France, which was instantly granted; 
and this is the second time that the sci- 
ences have heen thus privileged. On 
tne 11th of March, 1806, the council of 
state decitled on giving Captain Flinders 
his fiberty, and on restoring his galley, 
the Cumberland, yulaie 
The sixth volume of the Memoirs of 
the Institute for the Class of Sciences 
contains an eulogy upon M. Méchain, 
and a new formula to reduce distance es, 
by several observations, by Messrs. Mé- 
chain, Messier, Burckhardt, a and Lalande, 
my nephew Wet myself have there piven 
the results of the transit of Mercury in 
1802, and the consequences resulting 
frou it, in order to correct my tables. 
M. Coulomb has also corsmenicated to 
the public, through the same medium, 
“ Methods for obtaining the greatest De- 
cree of Magnetism ;” and M. Buache, a 
Memoir upon the discovery of hteones, 
\ herein 
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