Hisiory of Astronomy for the Year 1805. 237 
the case of animal exertion, however, considerable uncer- 
tainty always prevails,in consequence of the unequal powers 
of animals of the same species, and varying vigour of the 
same animal. The information which I have received in 
reply to inquiries respecting the weights raised in one hour 
by horses in different situations, has varied as far as from 
6 to 15 tons to the height of 100 feet. But although the 
rate at which mechanic force is generated may vary, any 
quantity of work executed is the same in whatever time it 
may have been performed. 
In short, whether we are considering the seurces of ex- 
tended exertion or of accumulated energy, whether we com- 
pare the accumulated forces themselves by their gradual or 
by their sudden effects, the idea of mechanic. force in prac= 
tice is always the same, and is proportional to the space 
through which any moving force is exerted or overcome, or 
to the square of the velocity of a body in which such force 
is accumulated. 
XXXIX. History of Astronomy for the Year 1805. By 
JEROME DE LALANDE*, 
Ox the morning of the 20th of October 1805, M. Bouvard. 
discovered a comet upon the paws of Ursa Major: it was 
small, had no tail, and was almost round, and so faint that 
it was scarcely discernible with a night-glass which mag- 
hified five or six times. At 4° 19’ in the morning it had 
166° 31’ of right ascension, which I call equatude, and 33° 
30° of northern declination. The same night it was disco- 
vered by M. Pons, at Marseilles. We know from the public 
journals that M. Huth saw it also at Frankfort on the 
Oder. Messrs. Bouvard and Arrago observed it with the 
great equatorial, made this year by M. Bellet for the ob- 
__ servatory ; and they followed it as long as the bad state of 
the weather would permit. M. Thulis observed it at Mar- 
seilles so late as the 6th of November. Messrs. Biot and 
* From Mag. Ency. for 1806, tom, ii. p. 92. 
Arrago 
