222 LEVELS OF tKANCE. 



Suppole tlien that the engineers of bridges and highways 

 were charged with the performance of this work, let us con- 

 lider how, after fome years, the exadlnefs of the refults, 

 which they had coIIe(5led, could be fufficienlly afcertained. 



Let us lake, for example, the bed of the Loire, whofe 

 courfe is of great extent. 



The chief engineers of the departments of the Upper Loire, 

 of the Loire, of the Saone and Loire, of the Nievre, of the 

 Loiret, of the Loire and Cher, of the f ndre and Loire, of the 

 Mayenne and Loire, and of the Lower Loire, would be or- 

 dered to furnifh, during the year, the levels of that part of 

 the courfe of the Loire which traverfed their refpeCtive de- 

 partments. 



According to the new organization of the fervice of bridge* 

 and highways, thefe nine departments require twenty-two en- 

 gineers, in the diflrid of each of whom would be found a 

 portion of the work to be performed. 



The total extent of the Loire is about ninety rauriamelers 

 (about 550 miles), which being divided among twenty-two 

 obfervers, would give to each of them little more than fortj 

 kilon.efers (about twenty-five miles) of levels to execute. 

 Leveis of the There is reafon to believe, from experience, that the twenty- 



Loire might be ^^^ engineers employed on the courfe of the river, would 

 engineers in thatfinift), in lefs than one featon, the levels of the whole river. 

 <di(iria, in one 'pjjg faj^g thing may be affirmed of the engineers placed in 

 the departments traverfed by the Rhine, the Seine, the Gi- 

 ronde, and the Rhone. It appears then beyond a doubt, that, 

 at the end of the firft year, the chief part of this phyfical chart 

 could be completed, to which the farther details might be af- 

 terwards added. 



Whatever care may be beftowed in taking levels, their ve- 

 rification is always an ufeful operation. That of the general 

 levels of France might be made as often, and in whatever cir- 

 Leveis of cumflances it (hould be judged neceffary. It would be fuffi- 



France, w"^" cient for this purpofe, to dire6t the newly appointed engineers 

 afterwards veri- to repeat, in the departments to which they might be fei^t, 

 fiedt>y the newly j|^g obfervations of their predeceflbrs ; which, betides the ad- 

 itecrs. vantage of confirming or correcting the reluHs already ob- 



tained, would give an opportunity to the new engineers of 

 acquiring, in perfon, a knowledge of the elevation of their 

 refpeftive diflri^s in relief. 



The 



