1807.] 
the History of the Comet of 1759; he 
also furnished Clairault with prodigious 
calculations, which he had occasion for, 
in order to establish the theory of that 
famous comet. Being charged in 1760 
with the editing of the Connoissance des 
Lemps, he entirely changed the plan of 
that useful work, and gave it the form in 
which it at present appears, He com- 
posed seventeen volumes of that collec- 
tion, and lett his example to his suc- 
cessors, 
All these calculations did not prevent 
him from producing, in 1764, the first 
edition of his great Treatise of Astro- 
nomy, a celebrated and classic work ; 
which, notwithstanding some minute ble- 
mishes, is a complete repertory of the 
science at that period, and of many me- 
thods either entirely new, or very little 
known. _ This work is his ‘principal claim 
to glory; he improved i it in two succeed- 
Ing editions; the first enriched with new 
tables for all the planets, and far superior 
to those of Halley and Cassini, He was 
the first who calculated the perturbations 
of Mars and Venus; and in the Theory 
of Satellites, in which little progress has 
been made, he explained a motion which 
Bailli Uiaed as a discovery made by 
himself. ‘he two competitors confined 
themselves to an exposition of their titles ; 
this literary dispute was conducted with 
decency, and the most probable result 
was, that the two celebrated astronomers 
had both been Jed to the same discove- 
ry, a circumstance not uncommon in re- 
searches founded on caiculation. 
Me composed all the astronomical ar- 
ticles for the Encyclopxdia of Yverdun, 
all those for the Supplements to the Ency- 
clopédie de Paris, and those for the Ency- 
hk a Methodigue, substituting for the 
articles which d’Alembert had ‘compiled 
from the works of Lemonnier, such as 
were more complete and more modern, 
all the materials for which he found in his 
great Treatise, that work after which all 
the astronomers who have acquired any 
reputation during the last forty years have 
formed themselves, 
To these written lessons he joined oral 
instructions for the space of forty-six years 
Since 1761 he had replaced his first mas- 
ter Delisle in the chair of astronomy in 
the College of France, and gave a new 
lustre to this curious part of public in- 
struction in a celebrated school which pos- 
sessed the most distinguished professors of 
every kind, which enjoyed and merited 
the extraordinary privilege of outliving the 
Eulogy on AL. de Lalande. 
253 
revolution and escaping the universal de- 
struction which levelled all round it. 
Of all the functions that he fulfilled, 
there was perhaps none that he took such 
delight in performing. Among the audi-- 
tors who were induced by curiosity or lei- 
sure to attend his lectures, he made a point 
of distinguishing the pupils who deserved 
his more particular attention; welcoming, 
encouraging, supporting, and ‘bringing i into 
notice all those who were likely to become 
useful. Thus his school became a kind 
of seminary which produced a multitude 
of disciples, who supplied the observato-~ 
ries and introduced on board of ships the 
use of imstruments and of astronomical 
methods. There also were formed seve- 
veral members of the academy, among 
whom it will be sufficient to mention 
Dagejet and Méchain. 
But a circumstance that deserves par- 
ticular notice 1s, that, notwithstanding the 
great number of pupils who.from gratis 
tude and attachment offered their ser- 
vices to aid him eithe im the immense 
caiculations which he had not time to 
make, or in the revision of his works, he 
never accepted any assistance without 
naming the real authors; and, not content 
with this durable testimony of his grati- 
tude, he used all possible nieans to give 
them more fugitive marks, but which 
were capable of being of more immediate 
and real benefit. Hence proceeded the 
articles which-he inserted in such profu- 
sion in the different journals. Most rea- 
ders ascribed them to an tordinate de= 
sire of fixing the attention of the public 
on himself; but the noble and secret mo- 
tive was to bring into notice new names 
or such as were but little known, to awa- 
ken or to keep up emulation, and to clear 
the way for humble merit. Several of 
these articles were at ditlerent times writ- 
ten with this intention for myself. This 
disclosure I owe to the memory of him 
whom I consider it an honour to have had 
for my instructor, and I congratulate my- 
self that the effects of his benevolence were 
productive of consequences so fortunate 
for me as a Sven my testimony on this 
melancholy ‘and solemn occasion a cna- 
racter of truth and authenticity which it 
could not have exhibited under any other 
circumstances. 
The same motive of gratitude dictated 
those biographical notices which imine- 
diately succeeded all our losses in Jitera- 
ture, arts and sciences. Notwithstanding 
his alarming weakness at the time, be 
mustered strength sufigient to crawl to 
the 
