brief word concerning Blaeu’s contributions toward the solution of problems having to do with terrestrial measurements, giving us in this word practically the only information we have concerning the matter. According to Picard, Blaeu’s measurements gave results with an error of but 66 meters, whereas for the same measurements, Snellius’s results gave an error of no less than 3880 meters. Had Blaeu more persistently carried on his studies in this particular branch of mathematical geography, his name doubtless would have been with the very first in a list of those who have made contribution to the science of terrestrial measurement and to a reform of the maps. His aim was set in the right direction, and we are safe in saying that none, in his day, made greater contribution toward the attainment of accuracy in map drawing than did he. To be able to understand the nature of the errors so common in chart making and to be able to correct the same were two very different matters, and although Blaeu was able to point out many errors, such, for example, as pertained to latitude and longitude, his maps do not indicate that he was able to overcome all difficulties. His was not the day for scientifically accurate results. Years had yet to pass before that end could be attained. To some of his errors, and to certain improvements of his, attention will be directed later. He appears to have been especially desirous, at all times, of acquiring detailed geographical and astronomical information from navigators who visited distant regions, making request of them that their observations should be reported to him. In a letter to W. Schickard, dated June 24, 1634, Blaeu wrote, “When the directors of the East India Company placed me at the head of their department of hydrography a year ago, I requested them to charge all pilots and masters who sailed for India to observe all eclipses, in whatever part they might be seen, and this has been done.”[15] His desire to be of assistance to others in giving out such information as might come into his possession is made evident by the further word in his letter to Schickard assuring him that “if observations of eclipses from India or other places on the way are sent to me, I shall be pleased to inform you of them.”