214 Notices respecting New Books. 
amounts to twenty; viz. six by Flamsteed, one by Bradley, one 
by Mayer, and twelve by Lemonnier. It was very natural for 
M. Bouvard to combine the ancient and modern series, in de- 
ducing the planetary elements. Having done so, and compared: 
his new tables with the observations, he found the ancient ones 
agreed but indifferently, while amnong the modern ones there-was 
a regularly varying difference alternately positive and negative. 
These differences were so great, that it was impossible to attri- 
bute them either to the modern observations, or to the theory; 
and the care with which the calculations had been made, pre- 
cluded the idea of assigning as the cause of the errors the omis- 
sion of any important term. M. Bouvard was therefore obliged 
to reject the ancient observations, and to construct his tables 
anew, according to the modern determinations solely; which now 
extend to nearly one half of the planetary period. The present 
tables correspond very exactly with the last-mentioned places, 
none of the comparisons giving a difference of 10”; but the an- 
cient observations are represented with much less exactness. 
Flamsteed’s exhibit errors of from +41” to +62”, and those of 
the other observers give from —14” to —70”. 
M. Bouvard leaves it to be ascertained hereafter, whether the 
above discordances are to be assigned to a want of exactness in 
the old observers and their instruments, as he himself believes ; 
or whether they depend on some unknown cause of planetary 
perturbation. 
To show the progress of modern science, we will call the at- 
tention of our readers to the tables published by Professor Vince 
in 1808, comprising the most exact ones then extant of the sun, 
moon, planete s, and satellites. Since that period there have ap- 
peared the tables of Venus, by Reboul; of the Moon, by Burck- 
hardt; of Jupiter’s satellites, by Delambre ; and of the three 
great planets, by Bouvard. Besides which, the tables of the Sun 
have been revised by Burckhardt, although, from the smallness 
of the corrections discovered by him, it has not been considered 
necessary to reconstruct the tables, So that Professor Vince’s 
work is become obsolete, in the short space of 13 years, except 
as to Mercury and Mars, of which planets new tables may be 
expected from the hand of M. Burckhardt, according to an in 
timation given in the Coun. des Tems for 1816, 
The First Volume of the Memoirs of the Astronomical Society 
of London, has appeared too late in the month to allow us to 
do more than merely notice its contents. In addition to the 
Address, Regulations and First Report of the Council of the So- 
ciety, it contains the following interesting papers: 
I, An _— of the Repeating Circle, and of the Wee 
all 
