V. MAPS, ETC. 661 



In the sessions held at Paris in 1872 this Committee removed all the general 

 doubts relating to the construction and comparison of the international proto- 

 types of weights and measures, and appointed a permanent committee in- 

 structed to carry on the work. The Spanish commissioner, Brigadier Ibaner, 

 was named president. 



The permanent Commission have spared no efforts to overcome the nume - 

 rous difficulties presented in the construction of the metre and kilogramme 

 and in the comparison with the metre of the French Archives. 



Their efforts have reached as far as the construction of two provisional 

 bars for the metre, and they are now proceeding to melt the irridiated plati- 

 num for the metres required. 



In the third pamphlet a description is given of the latest experiments. 



(3.) Numerical Results of the Levels of Precision taken be- 

 tween Alicante and Madrid, and Madrid and Santander. 



The results given are those which have been obtained in the two levelling 

 lines, giving the heights found in all the points of reference and the errors 

 which appear. 



(4.) Memoir upon the general compensation of the errors con- 

 tained in the geodesian net of Spain, by Don Toaquin Barraquer 

 and Don Francisco Cabello, Madrid, 1874. 



This memoir is a most important study of geodesy, applied to the net formed 

 by geodesical first class chains, which, following the direction of the meridians, 

 parallels, and coasts, comprehends the Spanish territory of the Peninsula. 



The authors of this memoir, by their intimate knowledge of all the theo- 

 retical studies published on this subject, have been enabled to give a practical 

 form to the immense work of compensating our net in such a manner that, as 

 they are able to take in the total extent of their undertaking, they can present 

 a rational division with all the scientific conditions required. 



(5.) Studies of Geodetic Levelling, by Don Carlos Ibaner, 

 1 vol., 4 to., pi., Madrid, 1864. 



The object of the author is to examine the accuracy of the different methods 

 employed up to the present time in geodesical studies to determine the third 

 co-ordinate of the zenith of triangulations, and most especially to apply the 

 practice of geodetic levelling to a theory presented 25 years ago by Biot, 

 which had never been tried in Spain or elsewhere. 



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

 Madrid, 1872. 



This book contains instructions for the observation of angles in geodesical 

 triangles, instructions to carry out the calculations, and instructions for the 

 persons appointed to make these studies. 



(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, an apparatus 

 for measuring bases, identical in character with the Spanish model ; he tested 



