324 
Sextants are made with great accuracy 
by M. Mendelsohn, at Berlin. 
The emperor having granted some in- 
struments to the Observatory at Turin, 
M. Charles Dominique Marie du Chayla 
has been appointed toit. 
He set out for Turin, in September 
1806, after having for some time been 
employed in the Observatory at Panis. 
The twenty-two foot telescope belong- 
ing to this Observatory has been re- 
fitted by M. Caroche, but its stand is too 
complicated; on which account it has 
been proposed to furnish it with another, 
although the present cost 50,000 francs. 
M. Caroche has discovered that it is very 
dificult to place a.mirror, weighing 400 
pounds, in such a way as not to change 
its form or position, when the telescope is 
pointed at different altitudes. 
The extraordinary results we were led 
to expect have not yet been furnished by 
the employment of Mr. Herschel’s forty- 
foot telescope. I wroteto him that I was 
anxious to visit England, in order to view 
this prodigious instrument, as soon as [ 
Jearned it would not be disagreeable to 
him; but as yet I have received no an- 
swer on the subject.. As Mr. Herschel is 
now about 68 years of age, I am afraid 
he will not be able to satisfy himself, and 
that it will be impossible to find a succes- 
sor capable of terminating, completely, so 
dithcult an enterprise. 
The métre des archives of the legisla- 
tive body, and that of the observatory, 
have been placed, by the new comparator 
of M. Le Noir, at 23° of the centigrade 
thermometer. They differ ouly by a 
600,000dth part from each other, but we 
cannot account for this difference; the 
comparison was made by Messrs. De- 
lambre, Prony, Burckhardt, and Bou- 
vard. 
M. Chevalier, keeper of the library at 
the Pantheon, who accompanied Mé- 
chain into Spain, has restored the Ob- 
servatory of Pingre, and furnished it with 
very excellent instruments. 
_ M. Leupold, who assisted me in my 
labours at Paris, has undertaken the re- 
establishment of the Observatory at Bor- 
deaux, aided by Messrs. Lescar, and Du- 
cum. They have applied to the admini- 
stration to assist them in defraying the 
expence of the necessary repairs, and pro- 
pose to procure a quadrant. This esta- 
blishment must, unquestionably, prove 
extremely useful ina place where there 
is sacha great number of seamen, 
During the present year, the marie 
department has furnished some works. 
Lalande’s History of Astronomy for 1806. 
[ Nov. ft, 
In the third volume, for 1806, of the 
Ephemerides of Coimbra, is contained 
a ‘Table of Longitudes, formed from the 
triangles of Portugal. The Hydrogra- 
phic Board at Madrid has also furnished 
several of them. We likewise find there 
a memoir on the rhomboidal reticule, 
and one on the use of the meridian glass, 
when it has a deviation, as also Demon- 
stracao € ampliacao do Calculo dos Eclipses 
proposto no primeiro volume das Epheme- 
rides de Coimbra, 1806. 
Bat this method does not appear to me 
to possess any advantage over the others ; 
it proceeds upon the Tables of the Ephe- 
merides of Coimbra. 
In the Klemens Historiques pratiques de 
la Marine, by M. Suzanne, 1s contained 
the calculation of the resistance of forces, 
with naval tactics and manoeuvres. 
M. Ducum, professor of navigation at 
Bordeaux, has published a memoir, en- 
titled, “ A new Method for determing 
the Latitude at Sea, by Altitudes taken 
from the Meridian, and the Longitude 
by an altitude of the Moon in several 
cases.” In this memoir, he points out 
the inconveniences into which we may 
fall, by employing the method of Dowes, 
and the precautions which are necessary 
in order to avoid them. He appears to 
have been unacquainted with the large 
work of M. Mendoza, who has treated 
of the same subject. 
With respect to the Méthode des Lon- 
gitudes, itis long since Lemonnier, Pin- 
gré, and myself, pointed out its utility. 
I myself noticed it particularly in my 
Abrigé de Navigatior, as being adapted 
considerably to simplify the method of 
finding the longitude, by means of the 
horary tables [£ published with that 
abridgement. 
The new lunar tables, by M. Biirg, serve 
for calculating the observations of longi- 
tudes made in the voyage to New Hol- 
land; and for this purpose Michael La- 
lande has calculated several observations 
of the meon at the meridian. 
It still remains for us to re-calculate 
the whole of the observations made in the 
three voyages of Captain Cook, because 
they were compared only with the lunar 
tables, of which we were at that time 
possessed, and which were not sufficient- 
ly exact to supply the place of corres- 
ponding observations. Geography has 
this year progressively advanced. 
Mungo Park,areport of whose death was 
some time ago prepagated, has already 
reached ‘Fombuctoo, in the heart of 
Africa, from whieh place he has written. 
On 
