| Description | In the letter Mendoza Rios sets out his refinement of the lunar distance method of determining longitude (a lunar distance is the distance between the moon and the sun or a fixed star. By comparing the local time when the lunar distance was observed with time predicted for the same lunar distance to occur at a known meridian, the difference in longitude could be deduced).
Mendoza Rios describes in his letter how he wishes to improve his method still further but requests the assistance of the Board of Longitude to do so. |