662 SEC. 15. GEOGRAPHY. 



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

 ever, 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 carrying out the operation, and they carried out the observations 

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

 probable error of +0'0011 mm . 



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

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

 rison of the Egyptian and Spanish rules. 



(8.) Plan of Madrid on a scale of ginnr- 



This plan consists of several sheets engraved on stone. 



The plan includes all the apparent 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 represented by contours, traced 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 goedesian studies 

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

 interdepending equations between the calculations of every station and those that 

 are required by 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 geodesian 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, in a 

 certain number of vertices of the first class net. These studies are carried 

 out by Don Manuel Morino. 



This volume contains other papers of high topographical interest. 



(10.) Topographical Map of Spain. 



The map of Spain on a scale of &Q ^ 00 is composed of about 1,078 sheets, 

 engraved in five colours, with numerous details. The sheets comprising 

 Madrid, Colmenar, Viejo, and Yetafe are already engraved. 



The general plan of the levellings used for Spain (plate 20) comprehend, 

 besides the line of Alicante to Santander, passing by Madrid, other lines 

 which, starting from Madrid run one to the N.E. which is to connect itself in 

 Perpignan with the French lines, another towards the south, which will serve 

 to determine the difference of levels between the observatories of Madrid and 

 St. Ferdinand, and other two which starting from Madrid will go to Lisbon 

 and Oporto. The remaining lines will complete this plan, and bring out 

 the levels of the capitals of provinces and towns of importance. 



