: ana. 



— 58 — 



2. pian in relief of This plan was constructed, as was the preceding, with 



the River Para- , _ x o; 



na in front of the obi ect of showing in a plastic form the results of the 



the city of Para- " ± 



na, scale moooo. surveys wich were carried out to serve as a basis for a pro- 

 ject for a Port for the City of Parana. For its construction 

 the same method was followed as for that of Rosario, the 

 curves of depths show the differences from meter to meter 

 and embrace all the zone that was studied in order to 

 select the best location for the future port. 



3. Portfolio of The entire course of the River Parana to its mouth in 



Maps of the Lo- 



River fa- the River Plate has been divided into three sections named 

 respectively Upper -, Middle- and Lower Parana. The first 

 section embraces the part of the river between Corrientes 

 and Santa Fe; the second that between Santa Fe and Ro- 

 sario, and the third that between Rosario and the mouth 

 of the Guazii; the approximate lengths of these sections are 

 508, 160, and 420 kilometres respectively. 



The aforementioned portfolio contains in IB sheets the 

 map of this section of the River to a scale of 1: 20,000. 



Rosario- River Plate; One index sheet to the scale of 

 1:100000. This plan indicates the relative position of the 

 different sheets which constitute the total survey. 



This survey is based on a triangulation which takes in 

 the two shores, the vertices are used as reference points to 

 fix the profiles of the soundings. These have been carried 

 out at variable distances, from a maximum of 200 metres 

 at points where great depths are found and navigation is 

 easy, to a minimum distance of 20 metres in the parts 

 where there is little depth, and where, therefore, the soun- 

 dings for each section are numerous and most closely taken 

 in the most interesting parts; the position of each sounding- 

 is referred to red signals on shore. The constant observations 

 at two automatic registering gauges erected in Rosario and 

 San Pedro, and at ten ordinary permanent gauges placed 

 at different points of the river during the execution of the 

 survey, gave the necessary elements to reduce the heights 

 of water observed to the hydraulic zeros. Besides these per- 

 manent gauges, temporary gauges were also erected and 

 continuously observed at the most important points, as at 

 the bars and shoals, during the time they were surveyed. 



The maps in the portfolio have been compiled from these 



