248 History of Astronomy for the Year 1805. 
culations. The first volume contains tables proper for calcu= 
lating without logarithms the horary angles, the azimuths, 
and the semi-diurnal arcs; the distances of the moon from 
the stars, to reduce the apparent distances to the true, and 
to find the longitude of a ship; formule for the calculation 
of eclipses, in which are employed the right ascensions and 
the declinations of the two stars ; and lastly, tables of Mars, 
by M. Monteiro, and which give the perturbations in ten 
equations, 
The volume of 1805 also presents several subsidiary tables, 
serving to calculate, without logarithms, the right ascension 
and the declination of a star whose longitude and latitude 
are known, and that according to two different methods: 
we there find a table of the horary angles of the stars when 
they have 8° of altitude, which has been constructed to find, 
among the eclipses of the satellites of Jupiter, any one which 
we cannot expect to be able to see; a table of the distances 
of the centre of Jupiter from the centre of the section of the 
cone of shadow through which the four satellites pass ; tables 
of latitude for these same satellites; the abscissa of the sha- 
dow, 7. e. the path of the satellite in the shadow during the 
semi-duration of the eclipse. These tables serve to compute 
the position of ‘the satellites with regard to the centre of 
Jupiter, such as we see them every six days of each month 
in the Ephemerides ; they also serve to ascertain whether 
the satellite is visible at the time of immersion or emersion. 
For the general tables, which the author had given in the 
’ preceding volume for the aberration, he has in this volume 
substituted others which are all similar to those of M. De- 
lambre, with this exception, that the quantities, in place of 
being in seconds, are in minutes and decimals: some of these 
tables are founded upon very ingenious plans of calculation, 
and the author has skilfully avoided the necessity of having 
recourse to the tables of logarithms: this calculation is not 
always so short as that by the known methods ; but we there 
find for the problems given in 1804, the advantage of not 
having occasion for any other ephemerides; far the pro- 
blems which that for 1805 contains, this advantage is much 
diminished, since we may refer to the yolume for 1804. 
The 
