two bases, one at Berlin in 1846 and the other at Bonn in 1847. The results of the former were announced in 1849, but the necessity for reobserving some of the adjacent angles delayed the publication regarding the latter until 1876.
The coast-triangulation was so well executed that it was deemed advisable to utilize it in degree determinations by connecting it with the Russian system. This was done by Baeyer and General von Tenner from 1850 to 1851, with every precaution then known, including remeasurement of bases and a careful comparison of the standards. The difference in the total length of sixteen sides they bad in common was only 0·505 metre.
His work occasionally overstepped the boundary-lines, establishing stations in other countries; these served as germs of larger growth, in many cases afterward nurtured by Baeyer's own hands. His advice was so frequently solicited, and when followed the results were so praised, as to induce him to prepare and submit to the Prussian Minister of War a memoir giving in detail a method for making a good map of Prussia. The principal improvement suggested, and afterward adopted, was in the more extensive use of triangulation, fixing in this way every point of importance, leaving but little intermediate ground to be located graphically.
His tastes for geodetic work were soon to be more fully gratified. Having passed rapidly through the lower grades, he was in 1858 made a lieutenant-general, and retired. It seems as though this eventual freedom to follow his own inclinations had in early life impressed itself upon him, for we find that in his work when he came to a station that at some future time might be of geodetic importance, he bestowed upon it especial care, supplementing the usual series of observations with those that would obviate the necessity of reoccupying it. Before indecision as to what should next receive his attention had become wearisome, Struve secured his co-operation in extending the Russian arc of longitude along the fiftieth parallel into Prussia. This he had in hand during 1858, making only astronomic observations, as it was his purpose to use the triangulation previously made. After several interruptions, owing to the withdrawal of the officers detailed to assist, he decided to make Rauenberg his central point, and to determine the direction of the chain by the azimuth of the line from this station to the Marien-Dom in Berlin—a line which now orients the entire Prussian survey.
The association with Müffling, Bessel, and Struve gave to Baeyer the incentive to connect and unify the excellent geodetic work of middle Europe; geographically, his native land occupied a favored place, and his government fostered the scheme. In 1861 the plan for a middle European degree-measurement, drawn up by Baeyer and sanctioned by the Minister of War, was approved by the emperor. At once the co-operation of the states that were to participate was re-
