The following device has been designed to facilitate the computation of latitude and azimuth from observations on Polaris. It is assumed that the computer has access to the tables of the declination and right ascension of the star, also of the right ascension of the mean Sun, from which he can find the star's hour angle in the usual way. There are conditions where it seems best to compute the values of latitudes and azimuth directly from observations, rather than to make use of tables computed for various latitudes, months, years and hour angles. It is for such conditions, and where the accuracy demanded is of the order of 0.′1, that this method has been designed.