ASSOCIATED WITH LACAILLE IN HIS LABOURS. 101 
as orbits, instead of parabolas, or even mere straight 
lines; attraction confined them within its immense do- 
main ; in short, these bodies ceased for ever to be liable 
to superstition regarding them as prognostics. 
The stringency, the importance of these results, would 
naturally increase in proportion as the resemblance be- 
tween the announced orbit and the real orbit became 
more evident. 
This was the motive that determined so many astron- 
omers to calculate the orbit of the comet minutely, from 
the observations made in 1759, throughout Europe. 
Bailly was one of those zealous calculators. In the 
present day, such a labour would scarcely deserve 
sptcial mention; but we must remark that the methods 
at the close of the eighteenth century were far from 
being so perfect as those that are now in use, and that 
they greatly depended on the personal ability of the in- 
dividual who undertook them. 
Bailly resided in the Louvre. Being determined to 
make the theory and practice of astronomy advance to- 
gether, he had an observatory established from the year 
1760, at one of the windows in the upper story of the 
south gallery. Perhaps I may occasion surprise by giv- 
ing the pompous name of Observatory to the space occu- 
pied by a window, and the small number of instruments 
that it could contain. I admit this feeling, provided it 
be extended to the Royal Observatory of the epoch, to 
the old imposing and severe mass of stone that attracts 
_the attention of the promenaders in the great walk of the 
Luxembourg. There also, the astronomers were obliged 
to stand in the hollow of the windows; there also they 
said, like Bailly: I cannot verify my quadrants either by 
the horizon or by the zenith, for I can neither see the 
