424 SIR RODERICK I. MURCHISON'S ADDRESS—EUROPE. [May 25, 1857. 



perhaps, more diversij&ed and offers more attractions to the phy- 

 sical geographer than any area of similar extent in Enrope. The 

 Spanish Government is now, however, removing this opprobrium, 

 through the agency of a commission composed of officers of the 

 Engineers, Artillery, Staff, and Navy. 



In 1854 the preparatory works were commenced for laying down 

 the Trigonometrical Survey of Spain. The principal base line was 

 measured on the plain near Madridejos, in the province of Toledo, 

 and on the road to Andalusia, about 100 kilometres from Madrid. 

 Its length is 1.4,480 metres. The first reconnaissances for several 

 systems of triangles were made in the same year 1854, and in 1855 

 and 1856. One of these follows the direction of the meridian of 

 Madrid, near which the primary base line is situated, and ends 

 northwards in the neighbourhood of Motril, resting on the great 

 mountain range the Sierra Nevada, and comprising in its network 

 the towns of Ciudad-Eeal, Jaen, and Granada. Towards the north 

 it is prolonged to Santander, including Segovia and Burgos. This 

 chain is extended eastward, following the coast till it joins that of 

 the triangles of the French Etat-Major on the Pyrenees, at the 

 stations of Biarritz and Baigorry. This portion comprises the 

 capitals of Bilboa and San Sebastian. 



Another series is extended in the direction of the parallel of 

 Madrid, and runs eastwards to the Mediterranean, resting on several 

 points of the French triangulation made by Mechain and Delambre, 

 and subsequently by Biot and Arago, for the prolongation of the 

 meridian of Dunkirk, and taking in the chief towns of Teruel and 

 Castellon de la Plana. Towards the west, this series passes by 

 x\vila, and for the most part following the direction of the Sierra de 

 los Gredos, terminating in the interior of Portugal, on stations of 

 the triangulation already made in that kingdom. 



Another secondary series, leaving the last mentioned, has a north- 

 ward course, terminating in the Cape Di Peiias, taking in Salamanca, 

 Zamora, Leon, and Oviedo, all capitals of provinces. This chain is 

 intersected perpendicularly by another which commences from that 

 of the meridian of Madrid, to the south of Burgos, and runs 

 westward, taking in Palencia, and following nearly the northern 

 boundary of Portugal, until it reaches the sea near Vigo. 



Another secondary chain of triangles has been similarly pro- 

 jected, which rests on that of the parallel of Madrid eastward, and 

 stretches northward to Pampeluna, to connect itself with the French 

 triangulation of the Pyrenees, passing by the Moncayo and between 



