60 FORESTRY IN SPAIN. 



who are required to reside permanently or occasionally 

 within the precincts of the forest ; and to works of 

 hydraulic engineering : wells, tanks, canals, and works of 

 irrigation. In connection with the information which has 

 been given in regard to published works, to which the 

 students have access, on matters pertaining to meteorology 

 and climatology as Departments of forest science, I think 

 it well first to make mention of works on hydraulic 

 engineering, and thereafter to advert to works connected 

 with the others. 



Of treatises on subjects pertaining to hydraulic engine- 

 ering the most instructive is one entitled Tratado de ayuas 

 y liiegos, por Don Andres Llaurado, Irtgeniero de monies 

 Jefe de Print eri Clase, Professor rfe Construction y Mecanica 

 Aplicata en la Escnela especial dtr Cuerpo, $c.$c. A treatise 

 on rivers and irrigation works, by D. Andre's Llaurado, 

 Chief of the first-class in Corps of Forest Engineers, and 

 Professor of Constructions and Applied Mechanics in the 

 School of Forestry. It is a treatise which, published in 

 1870, has reached a second edition, and meanwhile has 

 procured for the distinguished author high honours in 

 orders of knighthood in his own country, in Portugal, and 

 in France and Italy, and membership in numerous 

 scientific and agricultural societies in different parts of 

 Spain, in Russia, in Italy, in Piedmont, in France, and in 

 the United States of America. 



After an introduction, in which is given a brief review 

 of irrigation works in Spain, and a statement of economic 

 considerations involved in the enterprise, and of means by 

 which it might be further developed, the author devotes the 

 first part of his treatise to preliminary matters, discussing 

 in successive chapters : 1. The importance of irrigations, 

 and the climate of Spain. 2. The composition and nature 

 of waters of irrigation, and their effects on vegetation, and 

 on different crops. 3. The quantity of water required for 

 irrigation. 4. The price of recovering water, and employing 

 it in irrigation, f>. The current or flow, and the leading 



