264 THE POPULAR SCIENCE MONTHLY. 



two bases, one at Berlin in 1840 and the othei' at Bonn in 1847. The 

 results of the former were announced in 1849, but the necessity for 

 reobscrving some of the adjacent angles delayed the publication re- 

 garding the latter until 187G. 



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 Ten- 

 ner 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 had 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 Min- 

 ister 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 grati- 

 fied. 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 im- 

 pressed 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 ob- 

 servations with those that would obviate the necessity of reoccupying 

 it. Before indecision as to w^hat 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 Rauenbcrg his central point, and to de- 

 termine 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 Muffling, 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 bis government fostered the scheme. In 18G1 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- 



