Letter, from Wilhelm Struve to Sir John Herschel, dated at Dorpat Autograph letter signed by sender. Hopes to meet John Frederick William Herschel and [James] South in summer. Announces emperor's decision to support measurement of the 3.5° latitude meridian throughout the entire Russian empire. Wilhelm Struve is responsible for directing work in the north. Emphasizes the importance of maintaining correct linear standards uniform with both France and England. Requests a copy of the English standard so as to compare it with the Russian measurements of degrees. 10 March 1830