TOREENTS, ETC., BIT COSTA DE BASTELICA. 125 



rationally, with an adaptation of means to the end. From the time that 

 the extent of the sore which has to be cicatrized is known and defined, it is 

 easy to report beforehand on the importance of the work to be done, on the 

 expense it will entail, and on the time which will be required for its 

 execution. 



" It may be necessary to limit the operations to bring them within the 

 means at command, but what is done is done in accordance with a fixed 

 plan and with the assurance of success. 



" I do not conceal from myself that I expose my remarks to the charge of 

 being premature. I state them more for the future than for the present. 

 A work so colossal cannot be improvised. Every new idea requires to be 

 matured before it be accepted. It has got, when true, to pass through the 

 sieve of contradiction and opposition, but it issues in triumph. 



" The reboisement of the mountains, looked at from this point of view, has 

 already overcome obstacles ; and it has stood the test of public calamities. 

 It is making good its position day by day, and in proportion as it becomes 

 better understood, more and more will the necessity of developing it be felt. 



" To state my opinion in a few words, this is the necessary solution of the 

 matter : it is an efficacious one, and there exists not another for a problem 

 which we cannot elude, and which presents itself in a more and more 

 threatening aspect. 



" I shall esteem myself happy if by this treatise, which is imperfect, but 

 which is expressive of deep convictions, I may contribute to hasten on the 

 time when our beautiful rivers shall no longer inspire dread or bring danger, 

 but become magnificent highways of navigation." 



The title of the work of M. Costa bears that he treats not only of the 

 laws, causes, effects, and means of repressing torrents, but also of the means 

 of utilising them. Means of doing this are indicated again and again in the 

 course of the work, but the suggestions thus given exhaust not his views of 

 what may in this way be effected. 



" The great perturbations in the order of nature which leave often behind 

 them saddening traces of their occurrence," says he, "fulfil, nevertheless, a 

 useful, and it may be a necessary, function in the work of creation.' The 

 storms which create a turmoil in the atmosphere purify the air. Without 

 the cyclones of the Indian Ocean, the latitudes in which they occur^would not 

 be habitable. And storms on the sea help to prevent a tainting of the 

 waters, by commingling with the superficial layers waters from deeper layers 

 more nearly saturated with salt. 



"The inundations of water-courses, against which we seek to protect 

 ourselves now, have served to create fertile alluvia on gigantic deltas, and 

 on many rich valleys, some of them the most beautiful parts of the 

 earth, in which human society has been able to develope itself, and to bring 

 forth its marvels. 



" Even in our own times, beneficent inundations — natural or artificial — 

 by depositing in certain valleys an earth which is repairing an exhausted 

 land, are the means of generating wealth. We have, then, in inundations 

 a force or power which sometimes occasions ruin and devastation, but which 

 sometimes becomes a valuable instrument of good, according as its action 

 may be chaotic or controlled. 



" Having seen how this force may be controlled and kept within bounds, 

 it is reasonable to suppose, and I cannot but believe the supposition to be in 



