350 History of Astronomy for the Year 1805. 
or chronometers ; and the Board of Longitude has published 
them. That invented by M. Breguet at Paris, is described 
in the volume of the History of Mathematics of Montucla, 
where I have given the history of machines. 
Nautical astronomy has been enriched with an important 
book entitled “* A complete Collection of Tables for Navi- 
gation,” by M. Mendoza, a Spanish officer, who has re- 
sided some time in England; comprised m 727 pages, 
in large quarto. It contains all the tables necessary for cor- 
recting the altitudes and distances by the simplest method 
hitherto found out ; for it is reduced to the addition of three 
numbers, which we take from these tables. We have also 
tables of logarithms, semi-diurnal arcs, amplitudes, the 
most extensive table of the longitudes and latitudes of places 
on the earth, and, generally speaking, every thing that is 
requisite at sea. If we add to the above the horary tables 
which I published at great length in my Abridgment of 
Navigation, in 1793, sailors will require nothing more to 
know when they are in any part of the world; and I hope 
that, in spite of all the efforts of the English, the French 
will not be the last to profit by these advantages, under an 
emperor who ts so well acquainted with the importance of 
a navy. 
These tables render the calculations so easy, that naviga- 
tors would do wrong not to use this method of finding the 
longitude. M. Mendoza is at present occupied with a more 
complete treatise on nautical astronomy. 
M. Luyando has published at Madrid twenty-three charts, 
upon which we may find, by a pair of compasses, the sides 
or augles of spherical triangles within a few minutes, and 
the correction of the distances observed at sea within a few 
seconds. These charts, as well as those of M. Margett’s, at 
London, may be useful to navigators who are not fond of 
calculations, Those of M. Luyando will cost Jess, but 
their use is rather more difficult. 
M. Duval le Roi has published at Brest, Elements of Na- 
vigation, which are worthy of that able professor. 
M. Depaquit has published a new Theory of the Tides. 
1 did 
