790 SEC. 15. GEOGRAPHY. 



The actual state of geodetic studies in Spain is represented on a scale of 

 WooVoTTo- ^ e tn i c ^ black lines mark the triangles in the French and Por- 

 tuguese network, which is joined to the Spanish ; thinner black lines mark 

 the direction of the Spanish system ; the black lines of the plan point out the 

 quadrilateral directions or capitals of provinces. The localities of which the 

 latitudes are determined astronomically are marked with a blue semicircle ; 

 the localities in which the difference of longitudes is determined are marked 

 with a red semicircle ; the azimuths known are marked with a blue circum- 

 ference. The lines of levelling are traced with red ink, those already carried 

 out with a continued line, and those not yet carried out by dots. The loca- 

 lities in which benchmarks have been established are marked Avith a red cross. 



(2.) Publications relating to the International Commission on 

 the Metre. 



The determination of the metre and international kilogramme is one of the 

 most interesting problems of measurement. 



The International Commission assembled to determine this was formed of 

 members of all nations. 



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 of the metre of the French Archives. 



They have completed the construction of two provisional bars for the 

 metre, and they are now proceeding to melt the irridiated platinum 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 between 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 geodetic network of Spain, by Don Toaquin Barra- 

 quer and Don Francisco Cabello, Madrid, 1874. 



This memoir is a-most important study of geodesy, applied to the network 

 formed by geodetic lines of the first order, which, following the direction of the 

 meridians, parallels, and coasts, comprehends the Spanish territory of the 

 Peninsula. 



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

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



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

 employed up to the present time in geodetic 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 Toeen tried in Spain or elsewhere. 



