1800. ] 
been by the Office for Foreign Affairs. 
This tafk he performed with extraordinary 
diligence. He colleéted as many obferva- 
tions and determinations cf the longitude 
and latitude of places as he could, calcu- 
lated them anew, examined the whole of 
Caffini’s triangular menfurations in Ger- 
many, and the geodetic furveys of feparate 
diftritts ; and deduced therefrom, as the 
refult of his fatiguing laboms, a great 
number of exactly determined points on 
which he might conftruét the whole fke- 
Jeton of the maps. He calculated the pro- 
jection, and drew it himfelf on each fec- 
tion; and inferted on each fheet the attro- 
nomically fixed points. He then examin- 
ed every feparate map or draught ufed for 
the detail, compared them with the beft 
accounts of travels, with fingle memoirs, 
the marching-routes of armies, éc. and 
thus determined the value of thefe auxiliary 
materials.. In the orthography of the 
names of places, &c, he chiefly followed 
Bulching. This is the only true method 
to draw, from exifiing materials, exact 
maps of countries which have not yet 
been tvigonometrically and aftronomically 
laid down. Inthe courfe of four years 
this map of Germany, on nine large fheets, 
was completed, together with a general 
map. Soon after followed the map of the 
North of Italy, on three fheets 5 to render 
it perfect no expence was fpared, and both 
the drawing and engraving were execured 
ina mafterly manner. The government 
bought the fixed number of copies, and 
the Duke d’Ayen, too noble-minded and 
magnanimous to with to derive any profit 
from the undertaking, made a prefent of 
all the copper-plates to his engineer and 
aide de camp, Chaucard, as a reward for 
his trouble. When, during the conyul-. 
fions of the revolution, Chauchard eimi- 
grated from France, he fold all thefe plates 
to the geographer Dezauche, from whom 
the maps may now be purchafed. Mé-. 
chain’s trouble and defert in the execution 
of thefe maps was certainly equal to 
Chauchard’s, yet he performed his part 
without any reward or emolument! The 
maps are reckoned among the beft we yet 
have, apd they are ftill fought for and 
efteemed by connoifleurs. But how few 
geographers know, that the excellency of 
them was chiefly owing to Méchain, . 
The Connciffance des tems al ufage aes 
Ajironomes et des Navigateurs 1s one of 
the oldett af{tronomical annals, which the 
Royal Academy of Sciences in Paris pub- 
hifhed in an uninterrupted feries from their 
inftitution in the year 1679. The moft 
celebrated aftronomers of the Academy, 
Montary Mas, No. 63. 
Memoirs of Mechain. 153 
Picard, Lefebvre, Lieutaud, Godin, Ma- 
raldi, La Lande, Jeaurat, were, during the 
courfe of acentury, the calculators and 
editors of this aftronomical calendar. In 
the year 1786, Mechain received from the 
Academy the honourable commiffion to 
prepare and fuperintend the publication of 
thefe ephemerides of the Heavens ; and till 
the time of the general confafion in France, 
from the year 1788 to 1794, he edited fe- 
ven volumes of them. ° ‘s 
In the year 1784'the Englith Govern- 
ment caufed a trigonyemetrical janétion of 
the two mott celebrated obfervatories in 
Europe, of Greeawich and Paris, to be 
undertaken. And when in the year 1787 
Major- general Roy had completed his 
net of triangles from London to Dover, 
the French Academy was requefted to fend 
commiffioners to affit in connecting it 
acrofs the fea with Caffini’s net of trian- 
gles at Dover. Méchain had the honour 
to be nominated one of the three aftrono- 
mers appointed by the Academy for this 
important commiffion. He accordingly 
fet out for England, and on his part con- 
tributed not a little tothe fuccefsful ter- 
Mination of the undertaking; and the 
three commifiioners publithed conjointly 
an account of their operations*. 
When in 1791 it was propofed in the 
National Afftmbly to introduce an unifor- 
mity of weights and meatures throughout 
France, the project was fubmitted to the 
Royal Academy of Sciences for their opi- 
nion. They propofed to meafure for this 
purpofe an arc of the meridian from Dun- 
kirk to Barcelona. The admeafurement 
of the degree was accordingly committed 
to two of the ableft academicians, and 
Meéchain had again the honour to be ap- 
pointed one of the commiffioners. He un. 
dertook the fouthern part of the menfura- 
tion, in the Pyrenees and in Spain; De 
Lambre, the northern. The refults of 
this great and important undertaking are 
already known to our readers ; and we ex- 
pect to learn more concerning it from a 
work now printing at Paris, which wiil 
coniain a circumftantial detail of all the 
Operations and men{urations. 
During this menfuration Méchain was 
feveral times in the moft imminent danger. 
He had a very dangerous fallon one of his 
triangle {tations from one of the highett 
mountains in the Pyrenees. In Catalonia 
he nearly loft his life, while employed in 

* Expolé des Operations faites en France en 
1737, pour la Jonction des Odfervatoires de 
Paris et de Greenwich, par M. M. Caffni, 
Méchain et Le ie hae 1792, 4to. 
faving 


