470 ANNUAL RECOKD OF SCIENCE AND INDUSTRY. 



by levees. The vast crops of cotton, sugar, corn, and rice, 

 with all the existing wealth represented by lands in cultiva- 

 tion, its villages, plantations, and stock, are the direct fruits 

 of this method of protecting the country against overflow. 



Nevertheless it is true that the practical application of the 

 system is fatally defective, and that unless some radical im- 

 provement be made, no hope remains of opening to cultiva- 

 tion the immense districts of back lands now exposed to 

 annual inundation by reason of annual breaks in the levees. 

 The defects of the present system may be classified as due to 

 erroneous organization of the levees, insufficient elevations, 

 injudicious cross sections and poor construction, inadequate 

 arrangements for inspecting and grading, and faulty locations 

 of the embankments, which are often placed so near caving 

 banks as to insure an early destruction. The plan recom- 

 mended by the committee consists, first, in keeping open the 

 Atchafalaya and the La Fourche, and, if practicable, the re- 

 opening of the Plaquemine. Second, in a general levee sys- 

 tem extended from the head of the alluvial reo-ion to the 

 Gulf, and including the valleys of the tributary streams. 

 The country is divided into these natural drainage districts, 

 each of which should have a responsible chief engineer, clothed 

 with ample powers. Without some strong and simple organ- 

 ization, it is the deliberate opinion of this Commission that 

 the alluvial region can never be securely protected against 

 overflow. Mep. of Comm. of Engineers ^ p. 31. 



NEW HYDKAULIC CEMENT, 



A French chemist has succeeded in producing a mineral 

 composition which, it is claimed, surpasses hydraulic cement 

 in its use as a mortar, and in its resistance to the action of 

 water, while it is also said to be unafiected by air or acids, 

 and to acquire a stony hardness at 230, w4iich it retains 

 even in boiling water. It is prepared by subjecting a mixt- 

 ure of nineteen pounds of sulphur and forty-two pounds of 

 pulverized stone-ware and glass to a gentle heat, sufficient to 

 melt the sulphur, and stirring it until it forms a perfectly 

 homogeneous mass. It is then run into vessels and allowed 

 to cool. It melts at about 248, and can, like asphaltum, 

 be repeatedly used by heating it gently. 5 (7, XXXVII., 

 295. 



