TRANSACTIONS. 77 



devastations can no longer be prevented, the ingenuity of 

 Italian engineers has found a means of turning them to good 

 account, and of compelling even the momitain torrent, the 

 very symbol of uncontrollable fury, to repair or at least com- 

 pensate its own ravages. 



The enterprises to which I allude are among the most 

 remarkable triumphs of humanity over physical nature, and 

 they possess special interest as exhibiting almost the only 

 instance where a soil, which man has once used, abused, 

 exhausted, and at last abandoned, has been restored to his 

 dominion, re-occupied and again made subservient to the 

 purposes of social and industrial life. I refer to the suc- 

 cess of the Tuscan engineers in reclaiming a very large ex- 

 tent of marsh in the Yal di Chiana, in Tuscany, by proces. 

 ses which have been since employed in other parts of that 

 duchy, and the application of which elsewhere might save 

 vast territories from disease, sterility and desolation. 

 The streams which flowed through the Yai di Chiana had, 

 in consequence of the gradual elevation of their channels 

 and the filling up of the bed of the valley with gravel and 

 earth, overflowed their banks and transformed many square 

 leagues of ground into a barren and unhealthy marsh. Fos- 

 sonibroni undertook to reclaim these swamps, and succeed- 

 ed in restoring them to fertility and salubrity, by erecting 

 dams, embankments, and sluices in some places, and cut- 

 ting water-courses in others, so as to obtain the complete 

 control of the waters of the valley, and thus compel them 

 to deposit, at pleasure, the mud with which they were 

 charged in the inundations of winter. By this means, the 

 low grounds were first filled up, and then, by elevating the 

 embankments and dams, deposits were formed at still high- 

 er points, and thus not only was the general level of the 

 valley considerably raised, but its inclination was so chang- 

 ed, that the course of the streams which water it was re- 

 versed, and the Arno now receives affluents which, from 

 time immemorial, had discharged themselves into the Tiber. 



