But beyond the eastern shores of the Caspian no system of direct geodetic measurements by first-class triangulation has been possible, and the surveys of Asiatic Russia are separated from those of Europe by the width of that inland sea.
The close of the 19th century witnessed the forging of the final links in the great geodetic triangulation of India, so far as the peninsula is concerned.
St Petersburg, again, is connected with Greenwich by European systems of triangulation; and the Greenwich meridian is adopted by Russia as the zero for all her longitude values.
The Caucasus triangulation of 1860-1870 gave 89 ft.
These again have been connected by links of more or less regularity, so that, if the Baluchistan triangulation lacks the rigid accuracy of a " first class " system, it at least supports good topography on geographical scales.