l42 LEGISLATION ON T0REBNT8. 



it is not impracticable. In normal cases of inundations, of a temporary 

 character — the waters returning again to their usual bed — there may be 

 ascertained what marks exist of inundations which have occurred within 

 the most protracted period during which they can be enumerated — say 80 

 years. These indications supply a point of departure, in determining with 

 exactitude levels following the inclination of the river bed, so arranged as 

 to include in one line all the corresponding marks of one flood. The whole 

 ground, from the river to the most distant part reached by an inundation, 

 would thus be divided into a certain number of zones, subject each to a 

 different chance of inundation. All the lands included in one zone would 

 constitute a class subject to the same chance. What this is has next to be 

 determined ; and that may be done thus : — If the portions included in 

 the zone nearest to the river have been flooded upon an average three 

 times every year, the chance of inundation may be represented by the 

 fraction J|^. While the zone most remote, if flooded only once in the 

 course of the fifty years, would be represented by the fraction ji . The 

 value of the property in each zone being then determined, representing the 

 value by v v v", and the chances hjpp p", the -equivalent of the extent to 

 which the different classes were interested would be expressed by the 

 products p V, p v, p" i/', (fee. ; and to determine the quota of each party 

 interested, it is only necessary to multiply the value of the property by 

 the chance of the class to which it belongs, and the product by a constant 

 co-efficient, determined in such a way that the sum of the shares of all 

 interested will equal the whole expense. This co-efficient may be deter- 

 mined by the following equation, in which the total expenses, represented 



by S, co-efficient = j—. — - &c. 



It is an intricate question, and leaves much to be determined by the 

 syndic ; but the classes once formed, what follows is rigorously just. 



It has been stated, that it has been questioned whether the law of 1807 

 in superseding, abrogated the decree of 4th Thermidor, an VIII. 



The question was raised in the Chamber of Deputies, on the 12th April 

 1837, by M. Jaubert, acting in the name of a commission appointed to 

 examine a proposed law relative to the joint action of proprietors in works 

 undertaken on rivers of greater and lesser size. This they considered it 

 did, but others thought differently. That question has not now the interest 

 it then excited. In the one may be seen a development of the other. Both 

 related exclusively to the construction of dikes as means of protecting the 

 land against the devastations of rivers and torrents. 



In 1797 appeared the work by Favre, advocating the creation of planta- 

 tions as a means of more efficiently securing the object desired. The date 

 of M. Dugied's work, advocating the same measure, I have not ascertained. 

 In 1841 was published, printed by order of the Minister of Public Works" 

 the work by Surell, shewing the primary and almost absolute importance of 

 plantation, wl^ile the topical application of dikes may be necessary as a 

 secondary and subsidiary means of preventing devastations. And the 

 legislation of the present is of national application ; these laws wore of more 

 limited local application. 



In entering upon the consideration of this later legislation, it mav be 

 mentioned that from the first it was maintained by Surell that as things 



