V. MAPS, ETC. 791 



(6.) Instructions for Geodetic Studies. 1 vol., 8vo., pi., Madrid, 



1872. 



This book contains instructions for the observation of angles and the 

 calculations necessary in geodetic triangles, and general instructions for the 

 persons appointed to carry out the work. 



(7.) Comparison of the Geodetic Standard Bar belonging to 

 the Government of the Viceroy of Egypt with the one which 

 served to measure the central base of the Map of Spain, by Ismail 

 Effendi and Don Carlos Ibaner. 



M. Brunner constructed, by order of the Egyptian Government, a base- 

 measuring apparatus, identical in character with the Spanish pattern ; he 

 tested it in Paris in order to ascertain its co-efficient of expansion. It was, 

 however, indispensable to determine its length, and to do so the Spanish 

 geodetic bar was chosen. 



Ismail Effendi came to Madrid with the Cairo astronomical apparatus ; 

 Don Ibaner was appointed for this commission ; they both agreed as to the 

 manner of conducting the operation, and they carried out the observations 

 and calculations until they obtained the equation of the Egyptian bar with a 

 probable error of -f 0-001 l mm . 



A full account of this is given in the book exhibited ; the plate represents 

 the comparator mounted at the Observatory of Madrid, to verify the compa- 

 rison of the Egyptian and Spanish bars. 



(8.) Plan of Madrid on a scale of ^Va. 



This plan consists of several lithographed sheets, and includes all the details 

 of the capital of Spain, the houses, number of streets, the trees, public and 

 private gardens, and principal buildings. 



The sheets are divided into squares, with their corresponding letter 'and 

 number. 



The levels are given by contours, traced at metre distances with the 

 corresponding enumeration of the heights referred to the Mediterranean. 



(9.) Memoirs of the Geographical and Statistical Institute of 

 Madrid. 



This important work comprehends the result of the geodetic studies 

 between Salamanca and Madrid, terminated as far as the establishment of the 

 interdepending equations between the calculations of every station and those thai 

 are required for the compensation of the whole polygonal system, the observa- 

 tions taken at every station, an account of these, the calculations of the most 

 probable directions relating to every isolated station by the establishment of 

 the equations already alluded to, &c. 



The second memoir gives an account of the levelling of the line from Ali- 

 cante to Madrid. 



The third memoir describes the determination of latitudes and azimuths, 

 and comprehends the astronomical geodetic studies carried out by the 

 members of the Madrid Observatory for the Geographical Institute, in order to 

 ascertain with proper exactitude the latitudes, longitudes, and azimuths, of a 

 certain number of trigonometrical points of the first order. These studies- 

 were carried out by Don Manuel Morino. 



The volume contains other papers of high topographical interest. 



