"To describe all regions of the earth and to establish all local times would be tedious and unfeasible since, for innumerable times and for boundless regions, the meridians have been recorded with respect to Arin, in such a way that it would not be difficult to determine from this radix by geometrical and arithmetical rules the other places and times... if we are removed in longitude from this (place, namely Arin), then the distance between our place and the locality of Arin must be taken into account’ for calculating the mean positions of planets."