1603 
page is somewhat torn, so that the date of publication and the 
name of the printer are illegible. It is presumably printed by Hrrmao 
DE Campos, whose oldest known work was published in 1509 at 
Setubal. The copy found in Munich appears not to be a first edition, 
but a reprint of an earlier one. 
This little book contains directions for determining the latitude in 
different places, and how the latitude may be found by the Pole 
Star; there is further appended a list of the latitudes of various 
points along the west coast of Africa, the way in which the course 
of the ship can be followed on the map, and finally a calendar in 
which the longitude and the declination of the sun are given for every 
day in the year. In these tables it is assumed that a year contains 
366 days, so that the data are not quite correct for the years that 
are not leap-years, but considering the amount of accuracy which 
at that time could be attained in the determination of latitude, the 
error is not great, and (in this case) the accuracy of the data is 
sacrificed to simplicity in use. The book is therefore obviously 
arranged as a simple hand-book for the easy use of mariners. 
It might be thought that the values of the declination of the sun 
had been borrowed from RercGiomontanus’  “Ephemerides” and 
“Tabulae directionum’’, so that these works although not directly 
made use of by the Portuguese mariners, were at any rate indirectly 
applied to by them. It appears, however, that the inclination of 
the Eeliptie upon which the Portuguese tables are founded is 23°33’, 
while in REGIOMONTANUS’ tables the inclination is taken at 23°30’, 
so that a connection between the two tables is out of the question. 
Besides this copy of the “Directions” found in Munich, BENsSAUDE 
also provides a photographic reproduction of another rare Portuguese 
work, namely the “Almanach perpetuum” written by ABRAHAM 
Zacuto, who was Professor in Salamanka from 1474 to 1492. This 
work was originally written in Hebrew, but was translated into 
Portuguese by JosepH Vizinuo, mentioned above as a member of the 
commission instituded by King Juan II, for the promotion of the 
science of navigation. The copy of this Portuguese translation is 
printed in Leiria in 1496. 
In this work we find more complete tables for the positions of 
the sun according to a cycle of four years, three ordinary and one 
leap-year, and there is even a small correction introduced for the 
transition from one cycle to the next, as then the position of the 
sun would have slightly changed. 
These tables by Zacuro, which are also calculated upon the basis. 
of an inclination of 23°33’, in all probability form the source of the 
103 
Proceedings Royal Acad. Amsterdam. Vol. XVIII 
