As Professor Taylor has described, the Hariot ms. is largely concerned with the calculation of meridional parts. These calculations are of great interest not only as regards the question of priority, but also because they are based on a method which was more than fifty years in advance of contemporary mathematical knowledge. Although the ms. is paged and cross-referenced, the calculations are incomplete and inadequately explained; arithmetical errors (remarkably few when all calculations had to be done by long multiplication!) make absolute interpretation of all figures almost impossible. Considerable detail is thus unavoidable if the essential parts of the ms. are to be put on record and explained; though the most important point must be left unexplained. There can be little doubt that Hariot's calculations are original and independent.